JarUtils.java

/*
 * ******************************************************************************
 *  * Copyright 2015 See AUTHORS file.
 *  *
 *  * Licensed under the Apache License, Version 2.0 (the "License");
 *  * you may not use this file except in compliance with the License.
 *  * You may obtain a copy of the License at
 *  *
 *  *   http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  * Unless required by applicable law or agreed to in writing, software
 *  * distributed under the License is distributed on an "AS IS" BASIS,
 *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  * See the License for the specific language governing permissions and
 *  * limitations under the License.
 *  *****************************************************************************
 */

package com.uwsoft.editor.data;

//package com.google.doclava;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class JarUtils {
    /**
     * Returns the jar file used to load class clazz, or defaultJar if clazz was not loaded from a
     * jar.
     */
    public static JarFile jarForClass(Class<?> clazz, JarFile defaultJar) {
        String path = "/" + clazz.getName().replace('.', '/') + ".class";
        URL jarUrl = clazz.getResource(path);
        if (jarUrl == null) {
            return defaultJar;
        }

        String url = jarUrl.toString();
        int bang = url.indexOf("!");
        String JAR_URI_PREFIX = "jar:file:";
        if (url.startsWith(JAR_URI_PREFIX) && bang != -1) {
            try {
                return new JarFile(url.substring(JAR_URI_PREFIX.length(), bang));
            } catch (IOException e) {
                throw new IllegalStateException("Error loading jar file.", e);
            }
        } else {
            return defaultJar;
        }
    }


    public static JarFile getThisJar(Class<?> clazz) {

        String path = "/" + clazz.getName().replace('.', '/') + ".class";
        URL jarUrl = clazz.getResource(path);

        String url = jarUrl.toString();
        int bang = url.indexOf("!");
        String JAR_URI_PREFIX = "jar:file:";
        if (url.startsWith(JAR_URI_PREFIX) && bang != -1) {
            try {
                return new JarFile(url.substring(JAR_URI_PREFIX.length(), bang));
            } catch (IOException e) {
                throw new IllegalStateException("Error loading jar file.", e);
            }
        }

        return null;
    }

    /**
     * Copies a directory from a jar file to an external directory.
     */
    public static void copyResourcesToDirectory(JarFile fromJar, String jarDir, String destDir)
            throws IOException {
        for (Enumeration<JarEntry> entries = fromJar.entries(); entries.hasMoreElements();) {
            JarEntry entry = entries.nextElement();
            if (entry.getName().startsWith(jarDir + "/") && !entry.isDirectory()) {
                File dest = new File(destDir + "/" + entry.getName().substring(jarDir.length() + 1));
                File parent = dest.getParentFile();
                if (parent != null) {
                    parent.mkdirs();
                }

                FileOutputStream out = new FileOutputStream(dest);
                InputStream in = fromJar.getInputStream(entry);

                try {
                    byte[] buffer = new byte[8 * 1024];

                    int s = 0;
                    while ((s = in.read(buffer)) > 0) {
                        out.write(buffer, 0, s);
                    }
                } catch (IOException e) {
                    throw new IOException("Could not copy asset from jar file", e);
                } finally {
                    try {
                        in.close();
                    } catch (IOException ignored) {}
                    try {
                        out.close();
                    } catch (IOException ignored) {}
                }
            }
        }

    }

    private JarUtils() {} // non-instantiable
}