* Enabled correct API baseline (3.7) and fixed related API-check errors.

* Moved classes that are not part of the API to "internal" packages.
* Removed unnecessary classes.
* Simplified creation of checkers by providing alternative super class
and constructors.

33 files changed, 409 insertions, 194 deletions

diff --git a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckChecker.java b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckChecker.java
index 607b5cd7773..58359f9836f 100644
--- a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckChecker.java
+++ b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckChecker.java
@@ -10,17 +10,18 @@
  *******************************************************************************/
 package org.eclipse.cdt.codan.internal.checkers;
 
+import static java.util.Collections.singletonList;
+
 import java.io.File;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
 import org.eclipse.cdt.codan.core.externaltool.ConfigurationSettings;
-import org.eclipse.cdt.codan.core.externaltool.InvocationParametersProvider;
-import org.eclipse.cdt.codan.core.externaltool.SpaceDelimitedArgsSeparator;
-import org.eclipse.cdt.codan.core.model.AbstractExternalToolBasedChecker;
+import org.eclipse.cdt.codan.core.externaltool.InvocationParameters;
 import org.eclipse.cdt.codan.core.model.IProblemLocation;
-import org.eclipse.cdt.codan.ui.cxx.externaltool.CxxSupportedResourceVerifier;
-import org.eclipse.cdt.codan.ui.externaltool.CommandInvoker;
+import org.eclipse.cdt.codan.ui.cxx.externaltool.AbstractCxxExternalToolBasedChecker;
 
 /**
  * Checker that invokes <a href="http://cppcheck.sourceforge.net/">Cppcheck</a> when a C/C++ is
@@ -28,7 +29,7 @@ import org.eclipse.cdt.codan.ui.externaltool.CommandInvoker;
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
-public class CppcheckChecker extends AbstractExternalToolBasedChecker {
+public class CppcheckChecker extends AbstractCxxExternalToolBasedChecker {
 	private static final String TOOL_NAME = "Cppcheck"; //$NON-NLS-1$
 	private static final String EXECUTABLE_NAME = "cppcheck"; //$NON-NLS-1$
 	private static final String DEFAULT_ARGS = ""; //$NON-NLS-1$
@@ -51,10 +52,7 @@ public class CppcheckChecker extends AbstractExternalToolBasedChecker {
 	}
 
 	public CppcheckChecker() {
-		super(new InvocationParametersProvider(), new CxxSupportedResourceVerifier(),
-				new SpaceDelimitedArgsSeparator(), new CommandInvoker(),
-				new CppcheckOutputParserFactory(),
-				new ConfigurationSettings(TOOL_NAME, new File(EXECUTABLE_NAME), DEFAULT_ARGS));
+		super(new ConfigurationSettings(TOOL_NAME, new File(EXECUTABLE_NAME), DEFAULT_ARGS, false));
 	}
 
 	@Override
@@ -70,4 +68,10 @@ public class CppcheckChecker extends AbstractExternalToolBasedChecker {
 	protected String getReferenceProblemId() {
 		return ERROR_PROBLEM_ID;
 	}
+
+	@Override
+	protected List<AbstractOutputParser> createParsers(InvocationParameters parameters) {
+		AbstractOutputParser parser = new CppcheckOutputParser(parameters, this);
+		return singletonList(parser);
+	}
 }
diff --git a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParser.java b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParser.java
index 96a27e62867..6fc05439ea5 100644
--- a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParser.java
+++ b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParser.java
@@ -14,7 +14,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import org.eclipse.cdt.codan.core.CodanRuntime;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParser;
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
 import org.eclipse.cdt.codan.core.externaltool.IProblemDisplay;
 import org.eclipse.cdt.codan.core.externaltool.InvocationParameters;
 import org.eclipse.cdt.codan.core.model.IProblemLocation;
@@ -26,7 +26,7 @@ import org.eclipse.core.resources.IFile;
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
-class CppcheckOutputParser implements IOutputParser {
+class CppcheckOutputParser extends AbstractOutputParser {
 	// the pattern for parsing the message is:
 	//
 	// [/src/HelloWorld.cpp:19]: (style) The scope of the variable 'i' can be reduced
diff --git a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParserFactory.java b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParserFactory.java
deleted file mode 100644
index f29f58ba2fc..00000000000
--- a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/CppcheckOutputParserFactory.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2012 Google, Inc.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- *    Alex Ruiz  - initial API and implementation
- *******************************************************************************/
-package org.eclipse.cdt.codan.internal.checkers;
-
-import static java.util.Collections.singletonList;
-
-import java.util.List;
-
-import org.eclipse.cdt.codan.core.externaltool.IOutputParser;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParserFactory;
-import org.eclipse.cdt.codan.core.externaltool.IProblemDisplay;
-import org.eclipse.cdt.codan.core.externaltool.InvocationParameters;
-
-/**
- * @author alruiz@google.com (Alex Ruiz)
- */
-class CppcheckOutputParserFactory implements IOutputParserFactory {
-	@Override
-	public List<IOutputParser> createParsers(InvocationParameters parameters,
-			IProblemDisplay problemDisplay) {
-		IOutputParser parser = new CppcheckOutputParser(parameters, problemDisplay);
-		return singletonList(parser);
-	}
-}
diff --git a/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvokerTest.java b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvokerTest.java
new file mode 100644
index 00000000000..fafa8041ff9
--- /dev/null
+++ b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvokerTest.java
@@ -0,0 +1,127 @@
+/*******************************************************************************
+ * Copyright (c) 2012 Google, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Alex Ruiz  - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.codan.internal.core.externaltool;
+
+import static org.junit.Assert.assertArrayEquals;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.cdt.codan.core.externaltool.ConfigurationSettings;
+import org.eclipse.cdt.codan.core.externaltool.IArgsSeparator;
+import org.eclipse.cdt.codan.core.externaltool.ICommandLauncher;
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
+import org.eclipse.cdt.codan.core.externaltool.InvocationFailure;
+import org.eclipse.cdt.codan.core.externaltool.InvocationParameters;
+import org.eclipse.cdt.codan.core.externaltool.SpaceDelimitedArgsSeparator;
+import org.eclipse.cdt.codan.core.param.BasicProblemPreference;
+import org.eclipse.cdt.codan.core.param.MapProblemPreference;
+import org.eclipse.cdt.codan.core.test.CodanTestCase;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.IPath;
+
+/**
+ * Tests for <code>{@link ExternalToolInvoker}</code>.
+ *
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+@SuppressWarnings("nls")
+public class ExternalToolInvokerTest extends CodanTestCase {
+	private static final String EXTERNAL_TOOL_NAME = "TestTool";
+
+	private ConfigurationSettings configurationSettings;
+	private IArgsSeparator argsSeparator;
+	private List<AbstractOutputParser> parsers;
+	private CommandLauncherStub commandLauncher;
+
+	private ExternalToolInvoker externalToolInvoker;
+
+	@Override
+	public void setUp() throws Exception {
+		super.setUp();
+		createConfigurationSettings();
+		argsSeparator = new SpaceDelimitedArgsSeparator();
+		parsers = new ArrayList<AbstractOutputParser>();
+		commandLauncher = new CommandLauncherStub();
+		externalToolInvoker = new ExternalToolInvoker(commandLauncher);
+	}
+
+	private void createConfigurationSettings() {
+		configurationSettings = new ConfigurationSettings(EXTERNAL_TOOL_NAME, new File("testtool"),
+				"", false);
+		// Update current value of ConfigurationSettings from preferences.
+		MapProblemPreference preferences = createPreferences(new File("usr/local/testtool"),
+				"--debug=true --include=all", true);
+		configurationSettings.updateValuesFrom(preferences);
+	}
+
+	private MapProblemPreference createPreferences(File path, String args,
+			boolean shouldDisplayOutput) {
+		MapProblemPreference preferences = new MapProblemPreference();
+		preferences.addChildDescriptor(new BasicProblemPreference("externalToolPath", "Path"));
+		preferences.addChildDescriptor(new BasicProblemPreference("externalToolArgs", "Args"));
+		preferences.addChildDescriptor(new BasicProblemPreference("externalToolShouldDisplayOutput",
+				"Should Display Output"));
+		preferences.setChildValue("externalToolPath", path);
+		preferences.setChildValue("externalToolArgs", args);
+		preferences.setChildValue("externalToolShouldDisplayOutput", shouldDisplayOutput);
+		return preferences;
+	}
+
+	@Override
+	public boolean isCpp() {
+		return true;
+	}
+
+	// class C {
+	// };
+	public void testCommandLauncherGetsCalledCorrectly() throws Throwable {
+		loadcode(getAboveComment());
+		InvocationParameters parameters = new InvocationParameters(currentIFile, currentIFile,
+				currentIFile.getLocation().toOSString(), cproject.getProject().getLocation());
+		externalToolInvoker.invoke(parameters, configurationSettings, argsSeparator, parsers);
+		assertSame(cproject.getProject(), commandLauncher.project);
+		assertEquals(EXTERNAL_TOOL_NAME, commandLauncher.externalToolName);
+		String expectedExecutablePath = configurationSettings.getPath().getValue().toString();
+		assertEquals(expectedExecutablePath, commandLauncher.executablePath.toOSString());
+		String[] expectedArgs = { parameters.getActualFilePath(), "--debug=true", "--include=all" };
+		assertArrayEquals(expectedArgs, commandLauncher.args);
+		assertEquals(parameters.getWorkingDirectory(), commandLauncher.workingDirectory);
+		assertEquals(configurationSettings.getShouldDisplayOutput().getValue().booleanValue(),
+				commandLauncher.shouldDisplayOutput);
+		assertSame(parsers, commandLauncher.parsers);
+	}
+
+	private static class CommandLauncherStub implements ICommandLauncher {
+		IProject project;
+		String externalToolName;
+		IPath executablePath;
+		String[] args;
+		IPath workingDirectory;
+		boolean shouldDisplayOutput;
+		List<AbstractOutputParser> parsers;
+
+		@Override
+		public void buildAndLaunchCommand(IProject project, String externalToolName,
+				IPath executablePath, String[] args, IPath workingDirectory,
+				boolean shouldDisplayOutput, List<AbstractOutputParser> parsers) throws InvocationFailure,
+				Throwable {
+			this.project = project;
+			this.externalToolName = externalToolName;
+			this.executablePath = executablePath;
+			this.args = args;
+			this.workingDirectory = workingDirectory;
+			this.shouldDisplayOutput = shouldDisplayOutput;
+			this.parsers = parsers;
+		}
+	}
+}
diff --git a/codan/org.eclipse.cdt.codan.core/META-INF/MANIFEST.MF b/codan/org.eclipse.cdt.codan.core/META-INF/MANIFEST.MF
index 3f2598e76bd..632bdbb384d 100644
--- a/codan/org.eclipse.cdt.codan.core/META-INF/MANIFEST.MF
+++ b/codan/org.eclipse.cdt.codan.core/META-INF/MANIFEST.MF
@@ -20,4 +20,5 @@ Export-Package: org.eclipse.cdt.codan.core,
    org.eclipse.cdt.codan.core.test,
    org.eclipse.cdt.codan.ui",
  org.eclipse.cdt.codan.internal.core.cfg;x-friends:="org.eclipse.cdt.codan.core.cxx",
+ org.eclipse.cdt.codan.internal.core.externaltool,
  org.eclipse.cdt.codan.internal.core.model;x-friends:="org.eclipse.cdt.codan.core.cxx,org.eclipse.cdt.codan.core.test,org.eclipse.cdt.codan.ui"
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IOutputParser.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/AbstractOutputParser.java
index ddd460cb274..2e78ae8ab18 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IOutputParser.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/AbstractOutputParser.java
@@ -14,8 +14,10 @@ package org.eclipse.cdt.codan.core.externaltool;
  * Parses the output of an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
-public interface IOutputParser {
+public abstract class AbstractOutputParser {
 	/**
 	 * Parses one line of output. Implementations are free to create markers from the information
 	 * retrieved from the parsed output.
@@ -24,11 +26,11 @@ public interface IOutputParser {
 	 * @throws InvocationFailure if the output indicates that the invocation of the external tool
 	 *         failed.
 	 */
-	boolean parse(String line) throws InvocationFailure;
+	public abstract boolean parse(String line) throws InvocationFailure;
 
 	/**
 	 * Resets the value of this parser, usually after the execution of the external tool is
 	 * finished.
 	 */
-	void reset();
+	public abstract void reset();
 }
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ConfigurationSettings.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ConfigurationSettings.java
index 62cb816756e..52fafedf421 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ConfigurationSettings.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ConfigurationSettings.java
@@ -10,18 +10,19 @@
  *******************************************************************************/
 package org.eclipse.cdt.codan.core.externaltool;
 
-import static org.eclipse.cdt.codan.core.externaltool.Messages.ConfigurationSettings_args_format;
-import static org.eclipse.cdt.codan.core.externaltool.Messages.ConfigurationSettings_path_format;
-import static org.eclipse.cdt.codan.core.externaltool.Messages.ConfigurationSettings_should_display_output;
-
 import java.io.File;
 
 import org.eclipse.cdt.codan.core.param.MapProblemPreference;
+import org.eclipse.cdt.codan.internal.core.externaltool.ArgsSetting;
+import org.eclipse.cdt.codan.internal.core.externaltool.PathSetting;
+import org.eclipse.cdt.codan.internal.core.externaltool.ShouldDisplayOutputSetting;
 
 /**
  * User-configurable external tool settings.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class ConfigurationSettings {
 	private final PathSetting path;
@@ -31,38 +32,18 @@ public class ConfigurationSettings {
 
 	/**
 	 * Constructor.
-	 * <p>
-	 * <strong>Note:</strong> this constructor uses {@code false} as the default value of the
-	 * <code>{@link ShouldDisplayOutputSetting}</code> to create.
-	 * </p>
 	 * @param externalToolName the name of the external tool, to be displayed to the user.
 	 * @param defaultPath the default path of the external tool.
 	 * @param defaultArgs the default arguments to pass when invoking the external tool.
-	 */
-	public ConfigurationSettings(String externalToolName, File defaultPath, String defaultArgs) {
-		this.externalToolName = externalToolName;
-		String pathLabel = String.format(ConfigurationSettings_path_format, externalToolName);
-		this.path = new PathSetting(pathLabel, defaultPath);
-		String argsLabel = String.format(ConfigurationSettings_args_format, externalToolName);
-		this.args = new ArgsSetting(argsLabel, defaultArgs);
-		String shouldDisplayOutputLabel = ConfigurationSettings_should_display_output;
-		this.shouldDisplayOutput = new ShouldDisplayOutputSetting(shouldDisplayOutputLabel, false);
-	}
-
-	/**
-	 * Constructor.
-	 * @param externalToolName the name of the external tool, to be displayed to the user.
-	 * @param path specifies the path and name of the external tool to invoke.
-	 * @param args specifies the arguments to pass when invoking the external tool.
-	 * @param shouldDisplayOutput specifies whether the output of the external tools should be
+	 * @param defaultShouldDisplayOutput indicates whether output of an external tool should be
 	 *        displayed in an Eclipse console.
 	 */
-	public ConfigurationSettings(String externalToolName, PathSetting path, ArgsSetting args,
-			ShouldDisplayOutputSetting shouldDisplayOutput) {
+	public ConfigurationSettings(String externalToolName, File defaultPath, String defaultArgs,
+			boolean defaultShouldDisplayOutput) {
 		this.externalToolName = externalToolName;
-		this.path = path;
-		this.args = args;
-		this.shouldDisplayOutput = shouldDisplayOutput;
+		this.path = new PathSetting(externalToolName, defaultPath);
+		this.args = new ArgsSetting(externalToolName, defaultArgs);
+		this.shouldDisplayOutput = new ShouldDisplayOutputSetting(defaultShouldDisplayOutput);
 	}
 
 	/**
@@ -77,7 +58,7 @@ public class ConfigurationSettings {
 	 * Returns the setting that specifies the path and name of the external tool to invoke.
 	 * @return the setting that specifies the path and name of the external tool to invoke.
 	 */
-	public PathSetting getPath() {
+	public SingleConfigurationSetting<File> getPath() {
 		return path;
 	}
 
@@ -85,7 +66,7 @@ public class ConfigurationSettings {
 	 * Returns the setting that specifies the arguments to pass when invoking the external tool.
 	 * @return the setting that specifies the arguments to pass when invoking the external tool.
 	 */
-	public ArgsSetting getArgs() {
+	public SingleConfigurationSetting<String> getArgs() {
 		return args;
 	}
 
@@ -95,7 +76,7 @@ public class ConfigurationSettings {
 	 * @return the shouldDisplayOutput the setting that specifies whether the output of the external
 	 *         tools should be displayed in an Eclipse console.
 	 */
-	public ShouldDisplayOutputSetting getShouldDisplayOutput() {
+	public SingleConfigurationSetting<Boolean> getShouldDisplayOutput() {
 		return shouldDisplayOutput;
 	}
 
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IArgsSeparator.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IArgsSeparator.java
index 5c687a1fa35..85afa587f26 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IArgsSeparator.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IArgsSeparator.java
@@ -11,20 +11,19 @@
 package org.eclipse.cdt.codan.core.externaltool;
 
 /**
- * Parses and separates the value of an <code>{@link ArgsSetting}</code> into an array of
- * {@code String}s.
+ * Parses a given {@code String} containing the arguments to pass to an external tool and separates
+ * them into individual values.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public interface IArgsSeparator {
 	/**
-	 * Indicates that there are no arguments to pass to the external tool executable.
-	 */
-	String[] NO_ARGS = new String[0];
-
-	/**
-	 * Parses and separates the given value.
-	 * @param args contains the arguments to pass to the external tool executable.
+	 * Parses a given {@code String} containing the arguments to pass to an external tool and
+	 * separates them into individual values.
+	 * @param args contains the arguments to pass to the external tool
+	 *        executable.
 	 * @return the separated argument values.
 	 */
 	String[] separateArgs(String args);
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ICommandInvoker.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ICommandLauncher.java
index 37e98361a11..94322599cdf 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ICommandInvoker.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ICommandLauncher.java
@@ -16,10 +16,13 @@ import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IPath;
 
 /**
+ * Builds and launches the command necessary to invoke an external tool.
+ *
  * @author alruiz@google.com (Alex Ruiz)
  *
+ * @since 2.1
  */
-public interface ICommandInvoker {
+public interface ICommandLauncher {
 	/**
 	 * Builds and launches the command necessary to invoke an external tool.
 	 * @param project the current project.
@@ -35,5 +38,5 @@ public interface ICommandInvoker {
 	 */
 	void buildAndLaunchCommand(IProject project, String externalToolName, IPath executablePath,
 			String[] args, IPath workingDirectory, boolean shouldDisplayOutput,
-			List<IOutputParser> parsers) throws InvocationFailure, Throwable;
+			List<AbstractOutputParser> parsers) throws InvocationFailure, Throwable;
 }
\ No newline at end of file
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IInvocationParametersProvider.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IInvocationParametersProvider.java
index b2d6bb2b3e6..8d67dad3913 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IInvocationParametersProvider.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IInvocationParametersProvider.java
@@ -16,6 +16,8 @@ import org.eclipse.core.resources.IResource;
  * Provides the parameters to pass when invoking an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public interface IInvocationParametersProvider {
 	/**
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IOutputParserFactory.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IOutputParserFactory.java
deleted file mode 100644
index 008bb5ba1dc..00000000000
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IOutputParserFactory.java
+++ /dev/null
@@ -1,29 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2012 Google, Inc.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- *    Alex Ruiz  - initial API and implementation
- *******************************************************************************/
-package org.eclipse.cdt.codan.core.externaltool;
-
-import java.util.List;
-
-/**
- * Factory of instances of <code>{@link IOutputParser}</code>.
- *
- * @author alruiz@google.com (Alex Ruiz)
- */
-public interface IOutputParserFactory {
-	/**
-	 * Creates instances of <code>{@link IOutputParser}</code>.
-	 * @param parameters the parameters to pass when invoking an external tool.
-	 * @param problemDisplay displays problems found by the external tool.
-	 * @return the created parsers.
-	 */
-	List<IOutputParser> createParsers(InvocationParameters parameters,
-			IProblemDisplay problemDisplay);
-}
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IProblemDisplay.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IProblemDisplay.java
index a4a054d7478..49ce23b008d 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IProblemDisplay.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/IProblemDisplay.java
@@ -16,6 +16,8 @@ import org.eclipse.cdt.codan.core.model.IProblemLocation;
  * Reports problems found in code, reported by an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public interface IProblemDisplay {
 	/**
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ISupportedResourceVerifier.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ISupportedResourceVerifier.java
index 210ac8d326f..bc3db8f1025 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ISupportedResourceVerifier.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ISupportedResourceVerifier.java
@@ -17,22 +17,26 @@ import org.eclipse.core.resources.IResource;
  * Verifies that a <code>{@link IResource}</code> can be processed by an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public interface ISupportedResourceVerifier {
 	/**
 	 * Indicates whether the external tool is capable of processing the given
 	 * <code>{@link IResource}</code>.
 	 * <p>
-	 * The minimum requirements that the given {@code IResource} should satisfy are:
+	 * The minimum requirements that the given {@code IResource} should satisfy
+	 * are:
 	 * <ul>
 	 * <li>should be an <code>{@link IFile}</code></li>
 	 * <li>should be displayed in the current active editor</li>
 	 * <li>should not have any unsaved changes</li>
 	 * </ul>
 	 * </p>
+	 *
 	 * @param resource the given {@code IResource}.
-	 * @return {@code true} if the external tool is capable of processing the given file,
-	 *         {@code false} otherwise.
+	 * @return {@code true} if the external tool is capable of processing the
+	 *         given file, {@code false} otherwise.
 	 */
 	boolean isSupported(IResource resource);
 }
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationFailure.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationFailure.java
index 4e9236bf218..9c2f2df4563 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationFailure.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationFailure.java
@@ -14,6 +14,8 @@ package org.eclipse.cdt.codan.core.externaltool;
  * Indicates that invocation of an external tool failed.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class InvocationFailure extends Exception {
 	private static final long serialVersionUID = 1L;
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParameters.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParameters.java
index 118886e21ad..d9e24ff1491 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParameters.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParameters.java
@@ -17,6 +17,8 @@ import org.eclipse.core.runtime.IPath;
  * Parameters to pass when invoking an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class InvocationParameters {
 	private final IResource originalFile;
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParametersProvider.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParametersProvider.java
index b5fc6867f2b..db9867c4223 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParametersProvider.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/InvocationParametersProvider.java
@@ -16,6 +16,8 @@ import org.eclipse.core.resources.IResource;
  * Default implementation of <code>{@link InvocationParameters}</code>
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class InvocationParametersProvider implements IInvocationParametersProvider {
 	/**
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SingleConfigurationSetting.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SingleConfigurationSetting.java
index 6c795b4c758..c94df27a49f 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SingleConfigurationSetting.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SingleConfigurationSetting.java
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.cdt.codan.core.externaltool;
 
+import org.eclipse.cdt.codan.core.param.IProblemPreference;
 import org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor;
 import org.eclipse.cdt.codan.core.param.MapProblemPreference;
 
@@ -18,6 +19,8 @@ import org.eclipse.cdt.codan.core.param.MapProblemPreference;
  * @param <T> the type of the value this setting stores.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class SingleConfigurationSetting<T> {
 	private final IProblemPreferenceDescriptor descriptor;
@@ -70,7 +73,9 @@ public class SingleConfigurationSetting<T> {
 	 * by this setting.
 	 */
 	public void updateValue(MapProblemPreference preferences) {
-		Object o = preferences.getChildValue(descriptor.getKey());
-		value = valueType.cast(o);
+		IProblemPreference childDescriptor = preferences.getChildDescriptor(descriptor.getKey());
+		if (childDescriptor != null) {
+			value = valueType.cast(childDescriptor.getValue());
+		}
 	}
 }
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SpaceDelimitedArgsSeparator.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SpaceDelimitedArgsSeparator.java
index 0a79dbcf624..bcab3407376 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SpaceDelimitedArgsSeparator.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/SpaceDelimitedArgsSeparator.java
@@ -13,11 +13,15 @@ package org.eclipse.cdt.codan.core.externaltool;
 import java.util.regex.Pattern;
 
 /**
- * Separates the value of an <code>{@link ArgsSetting}</code> using an empty space as delimiter.
+ * Default implementation of <code>{@link IArgsSeparator}</code> that uses an empty space as
+ * the delimiter to separate the arguments to pass to an external tool.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class SpaceDelimitedArgsSeparator implements IArgsSeparator {
+	private static final String[] NO_ARGS = new String[0];
 	private static final Pattern EMPTY_SPACE_PATTERN = Pattern.compile("\\s+"); //$NON-NLS-1$
 
 	/**
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/model/AbstractExternalToolBasedChecker.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/model/AbstractExternalToolBasedChecker.java
index 928465eda14..467e7f9531c 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/model/AbstractExternalToolBasedChecker.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/model/AbstractExternalToolBasedChecker.java
@@ -5,12 +5,11 @@ package org.eclipse.cdt.codan.core.model;
 import java.util.List;
 
 import org.eclipse.cdt.codan.core.CodanCorePlugin;
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
 import org.eclipse.cdt.codan.core.externaltool.ConfigurationSettings;
 import org.eclipse.cdt.codan.core.externaltool.IArgsSeparator;
-import org.eclipse.cdt.codan.core.externaltool.ICommandInvoker;
+import org.eclipse.cdt.codan.core.externaltool.ICommandLauncher;
 import org.eclipse.cdt.codan.core.externaltool.IInvocationParametersProvider;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParser;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParserFactory;
 import org.eclipse.cdt.codan.core.externaltool.IProblemDisplay;
 import org.eclipse.cdt.codan.core.externaltool.ISupportedResourceVerifier;
 import org.eclipse.cdt.codan.core.externaltool.InvocationFailure;
@@ -32,10 +31,12 @@ import org.eclipse.core.resources.IResource;
  * <li>not have any unsaved changes</li>
  * </ol>
  * </p>
- * By default, implementations of this checker are not enable to run while the user types, since
+ * By default, implementations of this checker are not allowed to run while the user types, since
  * external tools cannot see unsaved changes.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public abstract class AbstractExternalToolBasedChecker extends AbstractCheckerWithProblemPreferences
 		implements IProblemDisplay {
@@ -44,7 +45,6 @@ public abstract class AbstractExternalToolBasedChecker extends AbstractCheckerWi
 	private final IInvocationParametersProvider parametersProvider;
 	private final ISupportedResourceVerifier supportedResourceVerifier;
 	private final IArgsSeparator argsSeparator;
-	private final IOutputParserFactory outputParserFactory;
 	private final ConfigurationSettings configurationSettings;
 	private final ExternalToolInvoker externalToolInvoker;
 	private final RootProblemPreference preferences;
@@ -56,20 +56,17 @@ public abstract class AbstractExternalToolBasedChecker extends AbstractCheckerWi
 	 *        external tool.
 	 * @param argsSeparator separates the arguments to pass to the external tool executable. These
 	 *        arguments are stored in a single {@code String}.
-	 * @param commandInvoker builds and launches the command necessary to invoke the external tool.
-	 * @param outputParserFactory creates parsers for the output of the external tool.
+	 * @param commandLauncher builds and launches the command necessary to invoke the external tool.
 	 * @param configurationSettings user-configurable external tool configuration settings.
 	 */
 	public AbstractExternalToolBasedChecker(IInvocationParametersProvider parametersProvider,
 			ISupportedResourceVerifier supportedResourceVerifier, IArgsSeparator argsSeparator,
-			ICommandInvoker commandInvoker, IOutputParserFactory outputParserFactory,
-			ConfigurationSettings configurationSettings) {
+			ICommandLauncher commandLauncher, ConfigurationSettings configurationSettings) {
 		this.parametersProvider = parametersProvider;
 		this.supportedResourceVerifier = supportedResourceVerifier;
 		this.argsSeparator = argsSeparator;
-		this.outputParserFactory = outputParserFactory;
 		this.configurationSettings = configurationSettings;
-		externalToolInvoker = new ExternalToolInvoker(commandInvoker);
+		externalToolInvoker = new ExternalToolInvoker(commandLauncher);
 		preferences = new SharedRootProblemPreference();
 	}
 
@@ -118,7 +115,7 @@ public abstract class AbstractExternalToolBasedChecker extends AbstractCheckerWi
 
 	private void invokeExternalTool(InvocationParameters parameters) throws Throwable {
 		updateConfigurationSettingsFromPreferences(parameters.getActualFile());
-		List<IOutputParser> parsers = outputParserFactory.createParsers(parameters, this);
+		List<AbstractOutputParser> parsers = createParsers(parameters);
 		try {
 			externalToolInvoker.invoke(parameters, configurationSettings, argsSeparator, parsers);
 		} catch (InvocationFailure error) {
@@ -133,6 +130,12 @@ public abstract class AbstractExternalToolBasedChecker extends AbstractCheckerWi
 	}
 
 	/**
+	 * Creates instances of <code>{@link AbstractOutputParser}</code>.
+	 * @param parameters the parameters to pass when invoking an external tool.
+	 */
+	protected abstract List<AbstractOutputParser> createParsers(InvocationParameters parameters);
+
+	/**
 	 * Handles a failure reported when invoking the external tool. This implementation simply
 	 * logs the failure.
 	 * @param error the reported failure.
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/param/SharedRootProblemPreference.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/param/SharedRootProblemPreference.java
index dea9e27f01e..e9fd456f91c 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/param/SharedRootProblemPreference.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/param/SharedRootProblemPreference.java
@@ -10,11 +10,12 @@
  *******************************************************************************/
 package org.eclipse.cdt.codan.core.param;
 
-
 /**
  * Preferences that can be shared among several problems.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class SharedRootProblemPreference extends RootProblemPreference {
 	@Override
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ArgsSetting.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ArgsSetting.java
index 311b04b7622..37d8a748d5e 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ArgsSetting.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ArgsSetting.java
@@ -8,27 +8,37 @@
  * Contributors:
  *    Alex Ruiz  - initial API and implementation
  *******************************************************************************/
-package org.eclipse.cdt.codan.core.externaltool;
+package org.eclipse.cdt.codan.internal.core.externaltool;
 
 import static org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor.PreferenceType.TYPE_STRING;
+import static org.eclipse.cdt.codan.internal.core.externaltool.Messages.ConfigurationSettings_args_format;
 
+import org.eclipse.cdt.codan.core.externaltool.SingleConfigurationSetting;
 import org.eclipse.cdt.codan.core.param.BasicProblemPreference;
+import org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor;
 
 /**
  * User-configurable setting that specifies the arguments to pass when invoking the external tool.
  * The arguments are stored in a single {@code String}.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class ArgsSetting extends SingleConfigurationSetting<String> {
 	private static final String KEY = "externalToolArgs"; //$NON-NLS-1$
 
 	/**
 	 * Constructor.
-	 * @param label the label to be displayed in the UI.
+	 * @param externalToolName the name of the external tool, to be displayed to the user.
 	 * @param defaultValue the default value of the setting.
 	 */
-	public ArgsSetting(String label, String defaultValue) {
-		super(new BasicProblemPreference(KEY, label, TYPE_STRING), defaultValue, String.class);
+	public ArgsSetting(String externalToolName, String defaultValue) {
+		super(newPreferenceDescriptor(externalToolName), defaultValue, String.class);
+	}
+
+	private static IProblemPreferenceDescriptor newPreferenceDescriptor(String externalToolName) {
+		String label = String.format(ConfigurationSettings_args_format, externalToolName);
+		return new BasicProblemPreference(KEY, label, TYPE_STRING);
 	}
 }
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvoker.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvoker.java
index e5aa17f23a4..ddf2bc61d4b 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvoker.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ExternalToolInvoker.java
@@ -15,8 +15,8 @@ import java.util.List;
 
 import org.eclipse.cdt.codan.core.externaltool.ConfigurationSettings;
 import org.eclipse.cdt.codan.core.externaltool.IArgsSeparator;
-import org.eclipse.cdt.codan.core.externaltool.ICommandInvoker;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParser;
+import org.eclipse.cdt.codan.core.externaltool.ICommandLauncher;
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
 import org.eclipse.cdt.codan.core.externaltool.InvocationFailure;
 import org.eclipse.cdt.codan.core.externaltool.InvocationParameters;
 import org.eclipse.core.resources.IProject;
@@ -27,38 +27,43 @@ import org.eclipse.core.runtime.Path;
  * Invokes an external tool to perform checks on a single file.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class ExternalToolInvoker {
-	private final ICommandInvoker commandInvoker;
+	private final ICommandLauncher commandLauncher;
 
 	/**
 	 * Constructor.
-	 * @param commandInvoker builds and launches the command necessary to invoke the external tool.
+	 *
+	 * @param commandLauncher builds and launches the command necessary to
+	 *        invoke the external tool.
 	 */
-	public ExternalToolInvoker(ICommandInvoker commandInvoker) {
-		this.commandInvoker = commandInvoker;
+	public ExternalToolInvoker(ICommandLauncher commandLauncher) {
+		this.commandLauncher = commandLauncher;
 	}
 
 	/**
 	 * Invokes an external tool.
+	 *
 	 * @param parameters the parameters to pass to the external tool executable.
 	 * @param configurationSettings user-configurable settings.
-	 * @param argsSeparator separates the arguments to pass to the external tool executable. These
-	 * arguments are stored in a single {@code String}.
+	 * @param argsSeparator separates the arguments to pass to the external tool
+	 *        executable. These
+	 *        arguments are stored in a single {@code String}.
 	 * @param parsers parse the output of the external tool.
-	 * @throws InvocationFailure if the external tool reports that it cannot be executed.
+	 * @throws InvocationFailure if the external tool reports that it cannot be
+	 *         executed.
 	 * @throws Throwable if the external tool cannot be launched.
 	 */
-	public void invoke(InvocationParameters parameters, ConfigurationSettings configurationSettings,
-			IArgsSeparator argsSeparator, List<IOutputParser> parsers) throws InvocationFailure,
-			Throwable {
+	public void invoke(InvocationParameters parameters, ConfigurationSettings configurationSettings, IArgsSeparator argsSeparator,
+			List<AbstractOutputParser> parsers) throws InvocationFailure, Throwable {
 		IPath executablePath = executablePath(configurationSettings);
 		String[] args = argsToPass(parameters, configurationSettings, argsSeparator);
 		boolean shouldDisplayOutput = configurationSettings.getShouldDisplayOutput().getValue();
 		IProject project = parameters.getActualFile().getProject();
 		try {
-			commandInvoker.buildAndLaunchCommand(project,
-					configurationSettings.getExternalToolName(), executablePath, args,
+			commandLauncher.buildAndLaunchCommand(project, configurationSettings.getExternalToolName(), executablePath, args,
 					parameters.getWorkingDirectory(), shouldDisplayOutput, parsers);
 		} finally {
 			reset(parsers);
@@ -70,21 +75,20 @@ public class ExternalToolInvoker {
 		return new Path(executablePath.toString());
 	}
 
-	private String[] argsToPass(InvocationParameters parameters,
-			ConfigurationSettings configurationSettings, IArgsSeparator argsSeparator) {
+	private String[] argsToPass(InvocationParameters parameters, ConfigurationSettings configurationSettings, IArgsSeparator argsSeparator) {
 		String[] configuredArgs = configuredArgs(configurationSettings, argsSeparator);
 		String actualFilePath = parameters.getActualFilePath();
 		return addFilePathToArgs(actualFilePath, configuredArgs);
 	}
 
-	private String[] configuredArgs(ConfigurationSettings configurationSettings,
-			IArgsSeparator argsSeparator) {
+	private String[] configuredArgs(ConfigurationSettings configurationSettings, IArgsSeparator argsSeparator) {
 		String args = configurationSettings.getArgs().getValue();
 		return argsSeparator.separateArgs(args);
 	}
 
 	private String[] addFilePathToArgs(String actualFilePath, String[] configuredArgs) {
 		int argCount = configuredArgs.length;
+		// TODO (alruiz) use array copy.
 		String[] allArgs = new String[argCount + 1];
 		// add file to process as the first argument
 		allArgs[0] = actualFilePath;
@@ -94,8 +98,8 @@ public class ExternalToolInvoker {
 		return allArgs;
 	}
 
-	private void reset(List<IOutputParser> parsers) {
-		for (IOutputParser parser : parsers) {
+	private void reset(List<AbstractOutputParser> parsers) {
+		for (AbstractOutputParser parser : parsers) {
 			parser.reset();
 		}
 	}
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/Messages.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/Messages.java
index c3f391382f4..6adbbc2dbcb 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/Messages.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/Messages.java
@@ -8,12 +8,14 @@
  * Contributors:
  *    Alex Ruiz  - initial API and implementation
  *******************************************************************************/
-package org.eclipse.cdt.codan.core.externaltool;
+package org.eclipse.cdt.codan.internal.core.externaltool;
 
 import org.eclipse.osgi.util.NLS;
 
 /**
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 @SuppressWarnings("javadoc")
 public class Messages extends NLS {
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/Messages.properties b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/Messages.properties
index fefe189a583..fefe189a583 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/Messages.properties
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/Messages.properties
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/PathSetting.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/PathSetting.java
index fb11bd6d5a5..378fab61be6 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/PathSetting.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/PathSetting.java
@@ -8,28 +8,38 @@
  * Contributors:
  *    Alex Ruiz  - initial API and implementation
  *******************************************************************************/
-package org.eclipse.cdt.codan.core.externaltool;
+package org.eclipse.cdt.codan.internal.core.externaltool;
 
 import static org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor.PreferenceType.TYPE_FILE;
+import static org.eclipse.cdt.codan.internal.core.externaltool.Messages.ConfigurationSettings_path_format;
 
 import java.io.File;
 
+import org.eclipse.cdt.codan.core.externaltool.SingleConfigurationSetting;
 import org.eclipse.cdt.codan.core.param.BasicProblemPreference;
+import org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor;
 
 /**
  * User-configurable setting that specifies the path and name of an external tool's executable.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class PathSetting extends SingleConfigurationSetting<File> {
 	private static final String KEY = "externalToolPath"; //$NON-NLS-1$
 
 	/**
 	 * Constructor.
-	 * @param label the label to be displayed in the UI.
+	 * @param externalToolName the name of the external tool, to be displayed to the user.
 	 * @param defaultValue the default value of the setting.
 	 */
-	public PathSetting(String label, File defaultValue) {
-		super(new BasicProblemPreference(KEY, label, TYPE_FILE), defaultValue, File.class);
+	public PathSetting(String externalToolName, File defaultValue) {
+		super(newPreferenceDescriptor(externalToolName), defaultValue, File.class);
+	}
+
+	private static IProblemPreferenceDescriptor newPreferenceDescriptor(String externalToolName) {
+		String label = String.format(ConfigurationSettings_path_format, externalToolName);
+		return new BasicProblemPreference(KEY, label, TYPE_FILE);
 	}
 }
diff --git a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ShouldDisplayOutputSetting.java b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ShouldDisplayOutputSetting.java
index 6ffb934dc8d..e3aaf704219 100644
--- a/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/core/externaltool/ShouldDisplayOutputSetting.java
+++ b/codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/externaltool/ShouldDisplayOutputSetting.java
@@ -8,27 +8,36 @@
  * Contributors:
  *    Alex Ruiz  - initial API and implementation
  *******************************************************************************/
-package org.eclipse.cdt.codan.core.externaltool;
+package org.eclipse.cdt.codan.internal.core.externaltool;
 
 import static org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor.PreferenceType.TYPE_BOOLEAN;
+import static org.eclipse.cdt.codan.internal.core.externaltool.Messages.ConfigurationSettings_should_display_output;
 
+import org.eclipse.cdt.codan.core.externaltool.SingleConfigurationSetting;
 import org.eclipse.cdt.codan.core.param.BasicProblemPreference;
+import org.eclipse.cdt.codan.core.param.IProblemPreferenceDescriptor;
 
 /**
  * User-configurable setting that specifies whether the output of an external tool should be
  * displayed in an Eclipse console.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ *
+ * @since 2.1
  */
 public class ShouldDisplayOutputSetting extends SingleConfigurationSetting<Boolean> {
 	private static final String KEY = "externalToolShouldDisplayOutput"; //$NON-NLS-1$
 
 	/**
 	 * Constructor.
-	 * @param label the label to be displayed in the UI.
 	 * @param defaultValue the default value of the setting.
 	 */
-	public ShouldDisplayOutputSetting(String label, boolean defaultValue) {
-		super(new BasicProblemPreference(KEY, label, TYPE_BOOLEAN), defaultValue, Boolean.class);
+	public ShouldDisplayOutputSetting(boolean defaultValue) {
+		super(newPreferenceDescriptor(), defaultValue, Boolean.class);
+	}
+
+	private static IProblemPreferenceDescriptor newPreferenceDescriptor() {
+		String label = ConfigurationSettings_should_display_output;
+		return new BasicProblemPreference(KEY, label, TYPE_BOOLEAN);
 	}
 }
diff --git a/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/AbstractCxxExternalToolBasedChecker.java b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/AbstractCxxExternalToolBasedChecker.java
new file mode 100644
index 00000000000..199267b0d09
--- /dev/null
+++ b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/AbstractCxxExternalToolBasedChecker.java
@@ -0,0 +1,63 @@
+/*******************************************************************************
+ * Copyright (c) 2012 Google, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Alex Ruiz  - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.codan.ui.cxx.externaltool;
+
+import org.eclipse.cdt.codan.core.externaltool.ConfigurationSettings;
+import org.eclipse.cdt.codan.core.externaltool.IArgsSeparator;
+import org.eclipse.cdt.codan.core.externaltool.IInvocationParametersProvider;
+import org.eclipse.cdt.codan.core.externaltool.ISupportedResourceVerifier;
+import org.eclipse.cdt.codan.core.externaltool.InvocationParametersProvider;
+import org.eclipse.cdt.codan.core.externaltool.SpaceDelimitedArgsSeparator;
+import org.eclipse.cdt.codan.core.model.AbstractExternalToolBasedChecker;
+import org.eclipse.cdt.codan.ui.externaltool.CommandLauncher;
+
+/**
+ * Base class for checkers that invoke external command-line tools to perform code checking
+ * on C++ files.
+ * <p>
+ * A file, to be processed by this type of checker, must:
+ * <ol>
+ * <li>a C++ file</li>
+ * <li>be in the current active editor</li>
+ * <li>not have any unsaved changes</li>
+ * </ol>
+ * </p>
+ * By default, implementations of this checker are not allowed to run while the user types, since
+ * external tools cannot see unsaved changes.
+ *
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+public abstract class AbstractCxxExternalToolBasedChecker extends AbstractExternalToolBasedChecker {
+	/**
+	 * Constructor
+	 * @param configurationSettings user-configurable external tool configuration settings.
+	 */
+	public AbstractCxxExternalToolBasedChecker(ConfigurationSettings configurationSettings) {
+		this(new InvocationParametersProvider(), new CxxSupportedResourceVerifier(),
+				new SpaceDelimitedArgsSeparator(), configurationSettings);
+	}
+
+	/**
+	 * Constructor.
+	 * @param parametersProvider provides the parameters to pass when invoking the external tool.
+	 * @param supportedResourceVerifier indicates whether a resource can be processed by the
+	 *        external tool.
+	 * @param argsSeparator separates the arguments to pass to the external tool executable. These
+	 *        arguments are stored in a single {@code String}.
+	 * @param configurationSettings user-configurable external tool configuration settings.
+	 */
+	public AbstractCxxExternalToolBasedChecker(IInvocationParametersProvider parametersProvider,
+			ISupportedResourceVerifier supportedResourceVerifier, IArgsSeparator argsSeparator,
+			ConfigurationSettings configurationSettings) {
+		super(parametersProvider, supportedResourceVerifier, argsSeparator, new CommandLauncher(),
+				configurationSettings);
+	}
+}
diff --git a/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CEditors.java b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CEditors.java
index b9b3c9e902d..1ab541ca65d 100644
--- a/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CEditors.java
+++ b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CEditors.java
@@ -24,9 +24,12 @@ import org.eclipse.ui.editors.text.TextEditor;
  * @author alruiz@google.com (Alex Ruiz)
  */
 @SuppressWarnings("restriction") // CEditor is internal API
-final class CEditors {
-
-	static TextEditor activeCEditor() {
+public final class CEditors {
+	/**
+	 * Finds the current {@code CEditor}.
+	 * @return the current {@code CEditor}, or {@code null} if one cannot be found.
+	 */
+	public static TextEditor activeCEditor() {
 		IWorkbench workbench = PlatformUI.getWorkbench();
 		for (IWorkbenchWindow w : workbench.getWorkbenchWindows()) {
 			IWorkbenchPage activePage = w.getActivePage();
diff --git a/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CxxSupportedResourceVerifier.java b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CxxSupportedResourceVerifier.java
index 4667d3b9731..d5a3c4b38ca 100644
--- a/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CxxSupportedResourceVerifier.java
+++ b/codan/org.eclipse.cdt.codan.ui.cxx/src/org/eclipse/cdt/codan/ui/cxx/externaltool/CxxSupportedResourceVerifier.java
@@ -20,11 +20,11 @@ import org.eclipse.core.resources.IResource;
 import org.eclipse.ui.editors.text.TextEditor;
 
 /**
- * Implemenation of <code>{@link ISupportedResourceVerifier}</code> for C/C++ files.
+ * Implementation of <code>{@link ISupportedResourceVerifier}</code> for C/C++ files.
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
-public class CxxSupportedResourceVerifier implements ISupportedResourceVerifier {
+class CxxSupportedResourceVerifier implements ISupportedResourceVerifier {
 	/**
 	 * Indicates whether the external tool is capable of processing the given
 	 * <code>{@link IResource}</code>.
diff --git a/codan/org.eclipse.cdt.codan.ui/META-INF/MANIFEST.MF b/codan/org.eclipse.cdt.codan.ui/META-INF/MANIFEST.MF
index f915a5f0dd0..03165322a3f 100644
--- a/codan/org.eclipse.cdt.codan.ui/META-INF/MANIFEST.MF
+++ b/codan/org.eclipse.cdt.codan.ui/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %Bundle-Name
 Bundle-SymbolicName: org.eclipse.cdt.codan.ui; singleton:=true
-Bundle-Version: 2.0.1.qualifier
+Bundle-Version: 2.1.0.qualifier
 Bundle-Activator: org.eclipse.cdt.codan.internal.ui.CodanUIActivator
 Bundle-Vendor: %Bundle-Vendor
 Require-Bundle: org.eclipse.ui,
diff --git a/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/CodanEditorUtility.java b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/CodanEditorUtility.java
index 7cb3830985c..016bcbc36ee 100644
--- a/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/CodanEditorUtility.java
+++ b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/CodanEditorUtility.java
@@ -160,6 +160,7 @@ public class CodanEditorUtility {
 	/**
 	 * Returns the active workbench page.
 	 * @return the active workbench page, or {@code null} if none can be found.
+	 * @since 2.1
 	 */
 	public static IWorkbenchPage getActivePage() {
 		IWorkbenchWindow activeWorkbenchWindow = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
diff --git a/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/CommandInvoker.java b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/CommandLauncher.java
index 5140080c4bf..cf371943b3f 100644
--- a/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/CommandInvoker.java
+++ b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/CommandLauncher.java
@@ -17,26 +17,28 @@ import java.io.InputStreamReader;
 import java.io.Reader;
 import java.util.List;
 
-import org.eclipse.cdt.codan.core.externaltool.ICommandInvoker;
-import org.eclipse.cdt.codan.core.externaltool.IOutputParser;
+import org.eclipse.cdt.codan.core.externaltool.ICommandLauncher;
+import org.eclipse.cdt.codan.core.externaltool.AbstractOutputParser;
 import org.eclipse.cdt.codan.core.externaltool.InvocationFailure;
-import org.eclipse.cdt.codan.internal.ui.CodanUIActivator;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IPath;
-import org.eclipse.ui.PartInitException;
 
 /**
  * Invokes an external tool command.
  *
  * @author alruiz@google.com (Alex Ruiz)
+ * 
+ * @since 2.1
  */
-public class CommandInvoker implements ICommandInvoker {
+public class CommandLauncher implements ICommandLauncher {
 	private static final String[] ENVIRONMENT_VARIABLE_SETTINGS = {};
 	
+	private ConsolePrinterFactory consolePrinterFactory = new ConsolePrinterFactory();
+	
 	@Override
 	public void buildAndLaunchCommand(IProject project, String externalToolName,
 			IPath executablePath, String[] args, IPath workingDirectory, boolean shouldDisplayOutput,
-			List<IOutputParser> parsers) throws InvocationFailure, Throwable {
+			List<AbstractOutputParser> parsers) throws InvocationFailure, Throwable {
 		ConsolePrinter consolePrinter = consolePrinter(externalToolName, shouldDisplayOutput);
 		String command = buildCommand(executablePath, args);
 		Process process = null;
@@ -60,14 +62,7 @@ public class CommandInvoker implements ICommandInvoker {
 	}
 
 	private ConsolePrinter consolePrinter(String externalToolName, boolean shouldDisplayOutput) {
-		if (shouldDisplayOutput) {
-			try {
-				return ConsolePrinterImpl.createOrFindConsole(externalToolName);
-			} catch (PartInitException e) {
-				CodanUIActivator.log("Unable to create/find console", e); //$NON-NLS-1$
-			}
-		}
-		return ConsolePrinter.NullImpl;
+		return consolePrinterFactory.createConsolePrinter(externalToolName, shouldDisplayOutput);
 	}
 	
 	private String buildCommand(IPath executablePath, String[] args) {
@@ -87,7 +82,7 @@ public class CommandInvoker implements ICommandInvoker {
 		return runtime.exec(command, ENVIRONMENT_VARIABLE_SETTINGS,	workingDirectory.toFile());
 	}
 	
-	private void processStream(InputStream inputStream, List<IOutputParser> parsers, 
+	private void processStream(InputStream inputStream, List<AbstractOutputParser> parsers, 
 			ConsolePrinter consolePrinter) throws IOException, InvocationFailure {
 		Reader reader = null;
 		try {
@@ -96,7 +91,7 @@ public class CommandInvoker implements ICommandInvoker {
 			String line = null;
 			while ((line = bufferedReader.readLine()) != null) {
 				consolePrinter.println(line);
-				for (IOutputParser parser : parsers) {
+				for (AbstractOutputParser parser : parsers) {
 					if (parser.parse(line)) {
 						break;
 					}
@@ -110,4 +105,9 @@ public class CommandInvoker implements ICommandInvoker {
 			}
 		}
 	}
+	
+	// Visible for testing.
+	void setConsolePrinterFactory(ConsolePrinterFactory newVal) {
+		this.consolePrinterFactory = newVal;
+	}
 }
diff --git a/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/ConsolePrinterFactory.java b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/ConsolePrinterFactory.java
new file mode 100644
index 00000000000..7a86efef316
--- /dev/null
+++ b/codan/org.eclipse.cdt.codan.ui/src/org/eclipse/cdt/codan/ui/externaltool/ConsolePrinterFactory.java
@@ -0,0 +1,30 @@
+/*******************************************************************************
+ * Copyright (c) 2012 Google, Inc. 
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Alex Ruiz  - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.codan.ui.externaltool;
+
+import org.eclipse.cdt.codan.internal.ui.CodanUIActivator;
+import org.eclipse.ui.PartInitException;
+
+/**
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+class ConsolePrinterFactory {
+	ConsolePrinter createConsolePrinter(String externalToolName, boolean shouldDisplayOutput) {
+		if (shouldDisplayOutput) {
+			try {
+				return ConsolePrinterImpl.createOrFindConsole(externalToolName);
+			} catch (PartInitException e) {
+				CodanUIActivator.log("Unable to create/find console", e); //$NON-NLS-1$
+			}
+		}
+		return ConsolePrinter.NullImpl;
+	}
+}