org.eclipse.wb.internal.swing.laf.LafUtils.java Source code

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Here is the source code for org.eclipse.wb.internal.swing.laf.LafUtils.java

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/*******************************************************************************
 * Copyright (c) 2011 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:
 *    Google, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.wb.internal.swing.laf;

import com.google.common.collect.Lists;

import org.eclipse.wb.internal.core.DesignerPlugin;
import org.eclipse.wb.internal.core.utils.jdt.core.CodeUtils;
import org.eclipse.wb.internal.swing.laf.model.LafInfo;
import org.eclipse.wb.internal.swing.laf.model.UserDefinedLafInfo;

import org.eclipse.core.runtime.IProgressMonitor;

import org.apache.commons.lang.StringUtils;

import java.io.File;
import java.lang.reflect.Modifier;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import javax.swing.LookAndFeel;

/**
 * Helper class to manage user-defined LAFs. Used by UI providing add/edit/delete operations.
 * 
 * @author mitin_aa
 * @coverage swing.laf
 */
public final class LafUtils {
    ////////////////////////////////////////////////////////////////////////////
    //
    // Private constructor
    //
    ////////////////////////////////////////////////////////////////////////////
    private LafUtils() {
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // JAR utilities
    //
    ////////////////////////////////////////////////////////////////////////////
    /**
     * Opens given <code>jarFile</code>, loads every class inside own {@link ClassLoader} and checks
     * loaded class for to be instance of {@link LookAndFeel}. Returns the array of {@link LafInfo}
     * containing all found {@link LookAndFeel} classes.
     * 
     * @param jarFileName
     *          the absolute OS path pointing to source JAR file.
     * @param monitor
     *          the progress monitor which checked for interrupt request.
     * @return the array of {@link UserDefinedLafInfo} containing all found {@link LookAndFeel}
     *         classes.
     */
    public static UserDefinedLafInfo[] scanJarForLookAndFeels(String jarFileName, IProgressMonitor monitor)
            throws Exception {
        List<UserDefinedLafInfo> lafList = Lists.newArrayList();
        File jarFile = new File(jarFileName);
        URLClassLoader ucl = new URLClassLoader(new URL[] { jarFile.toURI().toURL() });
        JarFile jar = new JarFile(jarFile);
        Enumeration<?> entries = jar.entries();
        while (entries.hasMoreElements()) {
            JarEntry entry = (JarEntry) entries.nextElement();
            String entryName = entry.getName();
            if (entry.isDirectory() || !entryName.endsWith(".class") || entryName.indexOf('$') >= 0) {
                continue;
            }
            String className = entryName.replace('/', '.').replace('\\', '.');
            className = className.substring(0, className.lastIndexOf('.'));
            Class<?> clazz = null;
            try {
                clazz = ucl.loadClass(className);
            } catch (Throwable e) {
                continue;
            }
            // check loaded class to be a non-abstract subclass of javax.swing.LookAndFeel class
            if (LookAndFeel.class.isAssignableFrom(clazz) && !Modifier.isAbstract(clazz.getModifiers())) {
                // use the class name as name of LAF
                String shortClassName = CodeUtils.getShortClass(className);
                // strip trailing "LookAndFeel"
                String lafName = StringUtils.chomp(shortClassName, "LookAndFeel");
                lafList.add(new UserDefinedLafInfo(StringUtils.isEmpty(lafName) ? shortClassName : lafName,
                        className, jarFileName));
            }
            // check for Cancel button pressed
            if (monitor.isCanceled()) {
                return lafList.toArray(new UserDefinedLafInfo[lafList.size()]);
            }
            // update ui
            while (DesignerPlugin.getStandardDisplay().readAndDispatch()) {
            }
        }
        return lafList.toArray(new UserDefinedLafInfo[lafList.size()]);
    }
}