Bug 165969 API to allow a contributed JRE and variables to be re-initialized

6 files changed, 270 insertions, 141 deletions

diff --git a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ContributedValueVariable.java b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ContributedValueVariable.java
new file mode 100644
index 000000000..5a3d23189
--- /dev/null
+++ b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ContributedValueVariable.java
@@ -0,0 +1,142 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2006 IBM Corporation and others.
+ * 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.internal.variables;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.variables.IValueVariable;
+import org.eclipse.core.variables.IValueVariableInitializer;
+import org.eclipse.core.variables.VariablesPlugin;
+import org.eclipse.osgi.util.NLS;
+
+/**
+ * Implementation of a value variable.
+ */
+public class ContributedValueVariable extends StringVariable implements IValueVariable {
+	
+	/**
+	 * Variable value or <code>null</code> if none 
+	 */
+	private String fValue;
+	
+	/**
+	 * Whether this variable's value has been initialized
+	 */
+	private boolean fInitialized = false;
+	
+	/**
+	 * Whether this variable is read only.  If true, users cannot change the value.
+	 */
+	private boolean fReadOnly;
+	
+	/**
+	 * Constructs a new value variable with the given name, description, read only
+	 * property and associated configuration element.  The value will be initialized
+	 * from the configuration element the first time getValue() is called.
+	 * 
+	 * @param name variable name
+	 * @param description variable description or <code>null</code>
+	 * @param readOnly whether the variable should be a read only variable
+	 * @param configurationElement configuration element
+	 */
+	public ContributedValueVariable(String name, String description, boolean readOnly, IConfigurationElement configurationElement) {
+		super(name, description, configurationElement);
+		fReadOnly = readOnly;
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IValueVariable#setValue(java.lang.String)
+	 */
+	public void setValue(String value) {
+		if (!isReadOnly() || !isInitialized()){
+			fValue = value;
+			setInitialized(true);
+			StringVariableManager.getDefault().notifyChanged(this);
+		}
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IValueVariable#getValue()
+	 */
+	public String getValue() {
+		if (!isInitialized()) {
+			initialize();
+		}
+		return fValue;
+	}
+
+	/**
+	 * Initialize this variable's value from the configuration element.
+	 */
+	private void initialize() {
+		if (getConfigurationElement() != null) {
+			// check for a explicit value specified in plug-in XML
+			String value = getConfigurationElement().getAttribute("initialValue"); //$NON-NLS-1$
+			if (value == null) {
+				// check for initializer
+				String className = getConfigurationElement().getAttribute("initializerClass"); //$NON-NLS-1$
+				if (className != null) {
+					try {
+						Object object = getConfigurationElement().createExecutableExtension("initializerClass"); //$NON-NLS-1$
+						if (object instanceof IValueVariableInitializer) {
+							IValueVariableInitializer initializer = (IValueVariableInitializer)object;
+							initializer.initialize(this);
+						} else {
+							VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0} - initializer must be an instance of IValueVariableInitializer.", new String[]{getName()}), null); //$NON-NLS-1$
+						}
+					} catch (CoreException e) {
+						VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0}",new String[]{getName()}), e); //$NON-NLS-1$
+					}
+				}
+			} else {
+				setValue(value);
+			}
+		}
+		setInitialized(true);
+	}
+
+	/**
+	 * Returns whether this variable has been initialized with a value by one of:
+	 * <ul>
+	 * <li><code>setValue(String)</code></li>
+	 * <li>its configuration element's <code>initialValue</code> attribute</li>
+	 * <li>its configuration element's initializer</li>
+	 * </ul>
+	 * @return whether this variable has been initialized with a value
+	 */	
+	protected boolean isInitialized() {
+		return fInitialized;
+	} 
+	
+	/**
+	 * Sets whether this variable has been initialized with a value.
+	 *  
+	 * @param initialized whether this variable has been initialized
+	 */
+	protected void setInitialized(boolean initialized) {
+		fInitialized = initialized;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IValueVariable#isReadOnly()
+	 */
+	public boolean isReadOnly() {
+		return fReadOnly;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IValueVariable#isContributed()
+	 */
+	public boolean isContributed() {
+		return getConfigurationElement() != null;
+	}
+
+}
diff --git a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariable.java b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariable.java
index 27d7d61c5..dc2448617 100644
--- a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariable.java
+++ b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariable.java
@@ -34,10 +34,11 @@ public abstract class StringVariable implements IStringVariable {
 	private IConfigurationElement fConfigurationElement;
 
 	/**
-	 * Constructs a new variable with the given name and description.
+	 * Constructs a new variable with the given name, description and configuration element.
 	 * 
 	 * @param name variable name
 	 * @param description variable description, or <code>null</code>
+	 * @param configurationElement configuration element or <code>null</code>
 	 */
 	public StringVariable(String name, String description, IConfigurationElement configurationElement) {
 		fName = name;
diff --git a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariableManager.java b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariableManager.java
index 8c3fd8a35..3694596be 100644
--- a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariableManager.java
+++ b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/StringVariableManager.java
@@ -93,14 +93,15 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 	
 	// Variable extension point constants
 	private static final String ATTR_NAME= "name"; //$NON-NLS-1$
-	private static final String ATTR_DESCRIPTION="description"; //$NON-NLS-1$	
+	private static final String ATTR_DESCRIPTION="description"; //$NON-NLS-1$
+	private static final String ATTR_READ_ONLY="readOnly"; //$NON-NLS-1$	
 	// Persisted variable XML constants
 	private static final String VALUE_VARIABLES_TAG= "valueVariables"; //$NON-NLS-1$
 	private static final String VALUE_VARIABLE_TAG= "valueVariable"; //$NON-NLS-1$
 	private static final String NAME_TAG= "name"; //$NON-NLS-1$
 	private static final String VALUE_TAG= "value"; //$NON-NLS-1$
 	private static final String DESCRIPTION_TAG="description"; //$NON-NLS-1$
-	private static final String INITIALIZED_TAG="contributed"; //$NON-NLS-1$
+	private static final String READ_ONLY_TAG="readOnly"; //$NON-NLS-1$
 	// XML values
 	private static final String TRUE_VALUE= "true"; //$NON-NLS-1$
 	private static final String FALSE_VALUE= "false"; //$NON-NLS-1$
@@ -200,8 +201,8 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 			fInternalChange = true;
 			fDynamicVariables = new HashMap(5);
 			fValueVariables = new HashMap(5);
-			loadPersistedValueVariables();
 			loadContributedValueVariables();
+			loadPersistedValueVariables();
 			loadDynamicVariables();
 			VariablesPlugin.getDefault().getPluginPreferences().addPropertyChangeListener(this);
 			fInternalChange = false;
@@ -228,7 +229,32 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 	}
 
 	/**
-	 * Loads any persisted value variables from the preference store.
+	 * Loads contributed value variables. This is done before loading persisted values.
+	 */
+	private void loadContributedValueVariables() {
+		IExtensionPoint point = Platform.getExtensionRegistry().getExtensionPoint(VariablesPlugin.PI_CORE_VARIABLES, EXTENSION_POINT_VALUE_VARIABLES);
+		IConfigurationElement elements[]= point.getConfigurationElements();
+		for (int i = 0; i < elements.length; i++) {
+			IConfigurationElement element = elements[i];
+			String name= element.getAttribute(ATTR_NAME);
+			if (name == null) {
+				VariablesPlugin.logMessage(NLS.bind("Variable extension missing required 'name' attribute: {0}", new String[] {element.getDeclaringExtension().getLabel()}), null); //$NON-NLS-1$
+				continue;
+			}
+			String description= element.getAttribute(ATTR_DESCRIPTION);
+			boolean isReadOnly = TRUE_VALUE.equals(element.getAttribute(ATTR_READ_ONLY));
+			
+			IValueVariable variable = new ContributedValueVariable(name, description, isReadOnly, element);
+			fValueVariables.put(name, variable);		
+		}		
+	}
+
+	/**
+	 * Loads persisted value variables from the preference store.  This is done after
+	 * loading value variables from the extension point.  If a persisted variable has the 
+	 * same name as a extension contributed variable the variable's value will be set to
+	 * the persisted value unless either a) The persisted value is <code>null</code>, or
+	 * b) the variable is read-only.
 	 */
 	private void loadPersistedValueVariables() {
 		String variablesString= VariablesPlugin.getDefault().getPluginPreferences().getString(PREF_VALUE_VARIABLES);
@@ -274,47 +300,22 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 				if (name.length() > 0) {
 					String value= element.getAttribute(VALUE_TAG);
 					String description= element.getAttribute(DESCRIPTION_TAG);
-					boolean initialized= TRUE_VALUE.equals(element.getAttribute(INITIALIZED_TAG));
-					ValueVariable variable= new ValueVariable(name, description, null);
-					if (initialized) {
-						variable.setValue(value);
+					boolean readOnly= TRUE_VALUE.equals(element.getAttribute(READ_ONLY_TAG));
+				
+					IValueVariable existing = getValueVariable(name);
+					if (existing == null){
+						ValueVariable variable = new ValueVariable(name, description, readOnly, value);
+						fValueVariables.put(name, variable);
+					} else if (!existing.isReadOnly() && value != null){
+						existing.setValue(value);
 					}
-					fValueVariables.put(name, variable);
 				} else {
 					VariablesPlugin.logMessage("Invalid variable entry encountered while loading value variables. Variable name is null.", null); //$NON-NLS-1$
 				}
 			}
 		}		
 	}
-
-	/**
-	 * Loads contributed value variables. This is done after the persisted value
-	 * variables are restored. Any contributed variables with the same name are
-	 * merged with existing persisted values.
-	 */
-	private void loadContributedValueVariables() {
-		IExtensionPoint point = Platform.getExtensionRegistry().getExtensionPoint(VariablesPlugin.PI_CORE_VARIABLES, EXTENSION_POINT_VALUE_VARIABLES);
-		IConfigurationElement elements[]= point.getConfigurationElements();
-		for (int i = 0; i < elements.length; i++) {
-			IConfigurationElement element = elements[i];
-			String name= element.getAttribute(ATTR_NAME);
-			if (name == null) {
-				VariablesPlugin.logMessage(NLS.bind("Variable extension missing required 'name' attribute: {0}", new String[] {element.getDeclaringExtension().getLabel()}), null); //$NON-NLS-1$
-				continue;
-			}
-			String description= element.getAttribute(ATTR_DESCRIPTION);
-			ValueVariable variable= new ValueVariable(name, description, element);
-			// if already present, merge with persisted value
-			ValueVariable existing = (ValueVariable)getValueVariable(name);
-			if (existing != null) {
-				if (existing.isInitialized()) {
-					variable.setValue(existing.getValue());
-				}					
-			}
-			fValueVariables.put(variable.getName(), variable);
-		}		
-	}
-
+	
 	/* (non-Javadoc)
 	 * @see org.eclipse.debug.internal.core.stringsubstitution.IStringVariableManager#getVariables()
 	 */
@@ -353,14 +354,16 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 	 * @see org.eclipse.debug.internal.core.stringsubstitution.IStringVariableManager#newValueVariable(java.lang.String, java.lang.String)
 	 */
 	public IValueVariable newValueVariable(String name, String description) {
-		IConfigurationElement element = null;
-		ValueVariable existing = (ValueVariable)getValueVariable(name);
-		if (existing != null && existing.isContributed()) {
-			element = existing.getConfigurationElement();
-		}
-		return new ValueVariable(name, description, element);
+		return newValueVariable(name, description, false, null);
 	}
-
+	
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IStringVariableManager#newValueVariable(java.lang.String, java.lang.String, boolean, java.lang.String)
+	 */
+	public IValueVariable newValueVariable(String name, String description, boolean readOnly, String value) {
+		return new ValueVariable(name, description, readOnly, value);
+	}
+	
 	/* (non-Javadoc)
 	 * @see org.eclipse.debug.internal.core.stringsubstitution.IStringVariableManager#addVariables(org.eclipse.debug.internal.core.stringsubstitution.IValueVariable[])
 	 */
@@ -447,19 +450,24 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 		Element rootElement= document.createElement(VALUE_VARIABLES_TAG);
 		document.appendChild(rootElement);
 		for (int i = 0; i < variables.length; i++) {
-			ValueVariable variable = (ValueVariable)variables[i];
-			Element element= document.createElement(VALUE_VARIABLE_TAG);
-			element.setAttribute(NAME_TAG, variable.getName());
-			String value= variable.getValue();
-			if (value != null) {
-				element.setAttribute(VALUE_TAG, value);
-			}
-			String description= variable.getDescription();
-			if (description != null) {
-				element.setAttribute(DESCRIPTION_TAG, description);
+			IValueVariable variable = variables[i];
+			if (!variable.isReadOnly()){
+				// don't persist read-only variables or un-initialized contributed variables 
+				if (!variable.isContributed() || ((ContributedValueVariable)variable).isInitialized()) {
+					Element element= document.createElement(VALUE_VARIABLE_TAG);
+					element.setAttribute(NAME_TAG, variable.getName());
+					String value= variable.getValue();
+					if (value != null) {
+						element.setAttribute(VALUE_TAG, value);
+					}
+					element.setAttribute(READ_ONLY_TAG, variable.isReadOnly() ? TRUE_VALUE : FALSE_VALUE);
+					String description= variable.getDescription();
+					if (description != null) {
+						element.setAttribute(DESCRIPTION_TAG, description);
+					}
+					rootElement.appendChild(element);
+				}
 			}
-			element.setAttribute(INITIALIZED_TAG, variable.isInitialized() ? TRUE_VALUE : FALSE_VALUE);
-			rootElement.appendChild(element);
 		}
 		return serializeDocument(document);
 	}
@@ -527,7 +535,7 @@ public class StringVariableManager implements IStringVariableManager, IPropertyC
 	 * 
 	 * @param variable the variable that has changed
 	 */
-	protected void notifyChanged(ValueVariable variable) {
+	protected void notifyChanged(IValueVariable variable) {
 		if (!fInternalChange) {
 			IValueVariable existing = getValueVariable(variable.getName());
 			if (variable.equals(existing)) {
diff --git a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ValueVariable.java b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ValueVariable.java
index dc92fe734..9efb48618 100644
--- a/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ValueVariable.java
+++ b/org.eclipse.core.variables/src/org/eclipse/core/internal/variables/ValueVariable.java
@@ -10,12 +10,7 @@
  *******************************************************************************/
 package org.eclipse.core.internal.variables;
 
-import org.eclipse.core.runtime.CoreException;
-import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.variables.IValueVariable;
-import org.eclipse.core.variables.IValueVariableInitializer;
-import org.eclipse.core.variables.VariablesPlugin;
-import org.eclipse.osgi.util.NLS;
 
 /**
  * Implementation of a value variable.
@@ -28,98 +23,54 @@ public class ValueVariable extends StringVariable implements IValueVariable {
 	private String fValue;
 	
 	/**
-	 * Whether this variable's value has been initialized
+	 * Whether this variable is read only.  If true, users cannot change the value.
 	 */
-	private boolean fInitialized = false;
+	private boolean fReadOnly;
 	
 	/**
-	 * Constructs a new value variable with the given name, description, and
-	 * associated configuration element.
+	 * Constructs a new value variable with the given name, description, read only
+	 * property and string value.  Value can be null.
 	 * 
 	 * @param name variable name
-	 * @param description variable description, or <code>null</code>
-	 * @param configurationElement configuration element or <code>null</code>
+	 * @param description variable description or <code>null</code>
+	 * @param readOnly whether the variable should be a read only variable
+	 * @param value the initial value of the variable or <code>null</code>
 	 */
-	public ValueVariable(String name, String description, IConfigurationElement configurationElement) {
-		super(name, description, configurationElement);
+	public ValueVariable(String name, String description, boolean readOnly, String value) {
+		super(name, description, null);
+		fReadOnly = readOnly;
+		fValue = value;
 	}
-
+	
 	/* (non-Javadoc)
-	 * @see org.eclipse.debug.internal.core.stringsubstitution.IValueVariable#setValue(java.lang.String)
+	 * @see org.eclipse.core.variables.IValueVariable#setValue(java.lang.String)
 	 */
 	public void setValue(String value) {
-		fValue = value;
-		setInitialized(true);
-		StringVariableManager.getDefault().notifyChanged(this);
+		if (!isReadOnly()){
+			fValue = value;
+			StringVariableManager.getDefault().notifyChanged(this);
+		}
 	}
-
+	
 	/* (non-Javadoc)
-	 * @see org.eclipse.debug.internal.core.stringsubstitution.IValueVariable#getValue()
+	 * @see org.eclipse.core.variables.IValueVariable#getValue()
 	 */
 	public String getValue() {
-		if (!isInitialized()) {
-			initialize();
-		}
 		return fValue;
 	}
 
-	/**
-	 * Initialize this variable's value.
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.variables.IValueVariable#isReadOnly()
 	 */
-	private void initialize() {
-		if (getConfigurationElement() != null) {
-			// check for a explicit value specified in plug-in XML
-			String value = getConfigurationElement().getAttribute("initialValue"); //$NON-NLS-1$
-			if (value == null) {
-				// check for initializer
-				String className = getConfigurationElement().getAttribute("initializerClass"); //$NON-NLS-1$
-				if (className != null) {
-					try {
-						Object object = getConfigurationElement().createExecutableExtension("initializerClass"); //$NON-NLS-1$
-						if (object instanceof IValueVariableInitializer) {
-							IValueVariableInitializer initializer = (IValueVariableInitializer)object;
-							initializer.initialize(this);
-						} else {
-							VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0} - initializer must be an instance of IValueVariableInitializer.", new String[]{getName()}), null); //$NON-NLS-1$
-						}
-					} catch (CoreException e) {
-						VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0}",new String[]{getName()}), e); //$NON-NLS-1$
-					}
-				}
-			} else {
-				setValue(value);
-			}
-		}
-		setInitialized(true);
+	public boolean isReadOnly() {
+		return fReadOnly;
 	}
-
-	/**
-	 * Returns whether this variable has been initialized with a value by one of:
-	 * <ul>
-	 * <li><code>setValue(String)</code></li>
-	 * <li>its configuration element's <code>initialValue</code> attribute</li>
-	 * <li>its configuration element's initializer</li>
-	 * </ul>
-	 * @return whether this variable has been initialized with a value
-	 */	
-	protected boolean isInitialized() {
-		return fInitialized;
-	} 
 	
-	/**
-	 * Sets whether this variable has been initialized with a value.
-	 *  
-	 * @param initialized whether this variable has been initialized
-	 */
-	protected void setInitialized(boolean initialized) {
-		fInitialized = initialized;
-	}
-
 	/* (non-Javadoc)
-	 * @see org.eclipse.debug.internal.core.stringsubstitution.IValueVariable#isContributed()
+	 * @see org.eclipse.core.variables.IValueVariable#isContributed()
 	 */
 	public boolean isContributed() {
-		return getConfigurationElement() != null;
+		return false;
 	}
 
 }
diff --git a/org.eclipse.core.variables/src/org/eclipse/core/variables/IStringVariableManager.java b/org.eclipse.core.variables/src/org/eclipse/core/variables/IStringVariableManager.java
index 731718a4e..db2fde0be 100644
--- a/org.eclipse.core.variables/src/org/eclipse/core/variables/IStringVariableManager.java
+++ b/org.eclipse.core.variables/src/org/eclipse/core/variables/IStringVariableManager.java
@@ -122,14 +122,27 @@ public interface IStringVariableManager {
 	public void validateStringVariables(String expression) throws CoreException;
 	
 	/**
-	 * Returns a new value variable with the given name and description.
+	 * Returns a new read-write value variable with the given name and description
+	 * with a <code>null</code> value.
 	 * 
 	 * @param name variable name, cannot be <code>null</code>
 	 * @param description variable description, possibly <code>null</code>
-	 * @return a new variable
-	 * @exception CoreException if a variable already exists with the given name
+	 * @return a new value variable
 	 */
 	public IValueVariable newValueVariable(String name, String description);
+
+	/**
+	 * Returns a new value variable with the given properties.
+	 * 
+	 * @param name variable name, cannot be <code>null</code>
+	 * @param description variable description, possibly <code>null</code>
+	 * @param readOnly whether this variable is to be a read only variable
+	 * @param value the string value to initialize this variable to - should
+	 * 	not be <code>null</code> for read-only variables
+	 * @return a new value variable
+	 * @since 3.3
+	 */
+	public IValueVariable newValueVariable(String name, String description, boolean readOnly, String value);
 	
 	/**
 	 * Adds the given variables to the variable registry.
diff --git a/org.eclipse.core.variables/src/org/eclipse/core/variables/IValueVariable.java b/org.eclipse.core.variables/src/org/eclipse/core/variables/IValueVariable.java
index 29a246547..a8b7b1470 100644
--- a/org.eclipse.core.variables/src/org/eclipse/core/variables/IValueVariable.java
+++ b/org.eclipse.core.variables/src/org/eclipse/core/variables/IValueVariable.java
@@ -15,7 +15,12 @@ package org.eclipse.core.variables;
  * a value variable is referenced does not effect the value of the variable.
  * A value variable can be contributed by an extension or created programmatically.
  * A contributor may optionally specify an initial value for a variable, or
- * provide a delegate that will initialize the variable with a value. 
+ * provide a delegate that will initialize the variable with a value.
+ * <p>
+ * Since 3.3, a variable can be specified as a "read only" preventing users from changing
+ * the value after it has been initialized.  Furthermore, a read only variable that is
+ * contributed by an extension will always load the value from the extension.
+ * </p>
  * <p>
  * Example of a value variable contribution with an initial value, the specified
  * variable is created with the initial value "/usr/local/foo".
@@ -49,10 +54,10 @@ package org.eclipse.core.variables;
 public interface IValueVariable extends IStringVariable {
 
 	/**
-	 * Sets the value of this variable to the given value. A value of
-	 * <code>null</code> indicates the value of this variable is undefined.
-	 * 
-	 * @param value variable value, possibly <code>null</code>
+	 * Sets the value of this variable to the given value.
+	 * Since 3.3, this has no effect if this variable is read only.
+	 *
+	 * @param variable value
 	 */
 	public void setValue(String value);
 	
@@ -71,9 +76,18 @@ public interface IValueVariable extends IStringVariable {
 	public boolean isContributed();
 	
 	/**
+	 * Returns whether this variable is read only.
+	 * 
+	 * @return whether this variable is read only
+	 * @since 3.3
+	 */
+	public boolean isReadOnly();
+	
+	/**
 	 * Sets the description of this variable to the given value.
 	 * 
 	 * @param description variable description, possibly <code>null</code>
 	 */
 	public void setDescription(String description);	
+	
 }