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/*******************************************************************************
* Copyright (c) 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.pde.tools.internal.versioning;
import java.io.*;
import java.net.URL;
import org.eclipse.core.runtime.*;
import org.eclipse.jdt.core.ToolFactory;
import org.eclipse.jdt.core.util.IClassFileReader;
import org.eclipse.osgi.util.NLS;
/**
* Helper class for dealing with class files.
*/
public class ClassFileHelper implements VersionCompareConstants {
/**
* Return a class file reader based on the given object or <code>null</code>.
*/
public static IClassFileReader getReader(Object object) throws CoreException {
if (object instanceof String)
return getClassReaderFromFile(new File((String) object));
if (object instanceof File)
return getClassReaderFromFile((File) object);
if (object instanceof URL)
return getClassReaderFromURL((URL) object);
if (object instanceof InputStream) {
IClassFileReader fileReader = ToolFactory.createDefaultClassFileReader((InputStream) object, IClassFileReader.ALL);
return fileReader;
} else if (object instanceof IClassFileReader)
return (IClassFileReader) object;
else
// otherwise throw CoreException
throw new CoreException(new Status(IStatus.WARNING, PLUGIN_ID, IStatus.WARNING, NLS.bind(Messages.JavaClassVersionCompare_unexpectedTypeMsg, object.getClass().getName()), null));
}
/**
* gets IClassFileReader of the java class denoted by <code>file</code>
* @param file java class file
* @return IClassFileReader instance or <code>null</code>if file type is wrong or any error occurred
*/
private static IClassFileReader getClassReaderFromFile(File file) {
if (isGivenTypeFile(file, CLASS_FILE_EXTENSION))
return ToolFactory.createDefaultClassFileReader(file.getAbsolutePath(), IClassFileReader.ALL_BUT_METHOD_BODIES);
if (isGivenTypeFile(file, JAVA_FILE_EXTENSION))
return null;
return null;
}
/**
* Checks whether or not the given file potentially represents a given type file on the file-system.
*
* @param file File instance which denotes to a file on the file-system
* @param type file type(e.g. "java","class")
* @return <code>true</code> <code>file</code> exists and is a configuration file,
* <code>false</code> otherwise
*/
private static boolean isGivenTypeFile(File file, String type) {
return file.isFile() && file.getName().endsWith(type);
}
/**
* Return a class file reader based on the contents of the given URL's input stream.
*
* @param url location of the class file
* @return the class file reader or <code>null</code>if any error occurred
*/
private static IClassFileReader getClassReaderFromURL(URL url) {
try {
InputStream input = url.openStream();
try {
return ToolFactory.createDefaultClassFileReader(input, IClassFileReader.ALL_BUT_METHOD_BODIES);
} finally {
if (input != null) {
input.close();
input = null;
}
}
} catch (IOException e) {
//ignore, result will be checked outside
}
return null;
}
}
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