com.topclouders.releaseplugin.helper.FileHelper.java Source code

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Here is the source code for com.topclouders.releaseplugin.helper.FileHelper.java

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/*
 * Copyright 20015 The Topclouders Hungary Ltd.
 *
 * 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.topclouders.releaseplugin.helper;

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

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

/**
 * 
 * 
 * @author Gabor Kokeny
 * @version 1.0.0
 *
 */
public class FileHelper {

    private final JarURLConnection jarURLConnection;

    private final JarFile jarFile;

    /**
     * FileHelper default constructor
     */
    private FileHelper(JarURLConnection jarURLConnection, JarFile jarFile) {
        this.jarURLConnection = jarURLConnection;
        this.jarFile = jarFile;
    }

    /**
     * This method will copy resources from the jar file of the current thread
     * and extract it to the destination folder.
     * 
     * 
     * @param resourcePath
     * @param destination
     */
    public static void copyResourceToDirectory(String resourcePath, File destination) {
        FileHelper.validateArguments(resourcePath, destination);

        try {
            URL resource = FileHelper.class.getClassLoader().getResource(resourcePath);
            JarURLConnection jarURLConnection = (JarURLConnection) resource.openConnection();
            JarFile jarFile = jarURLConnection.getJarFile();

            // Create a new file helper
            FileHelper fileHelper = new FileHelper(jarURLConnection, jarFile);
            fileHelper.copyResource(resourcePath, destination);
        } catch (IOException e) {
            throw new RuntimeException(
                    String.format("Failed to copy classpath resource to destination directory %s",
                            destination.getAbsolutePath()),
                    e);
        }

    }

    private static boolean validateArguments(String resourcePath, File destination) {
        if (resourcePath == null || resourcePath.isEmpty()) {
            throw new IllegalArgumentException("Method parameter 'resourcePath' cannot be null or empty string");
        }

        if (destination == null) {
            throw new IllegalArgumentException("Method parameter 'destination' cannot be null");
        } else if (destination.exists() && !destination.isDirectory()) {
            throw new IllegalArgumentException("Method parameter 'destination' must be a directory");
        }

        return true;
    }

    private void copyResource(String resourcePath, File destination) {
        FileHelper.validateArguments(resourcePath, destination);

        // Iterate on jar entries
        for (Enumeration<JarEntry> e = jarFile.entries(); e.hasMoreElements();) {

            JarEntry jarEntry = e.nextElement();

            final String jarEntryName = jarEntry.getName();
            final String jarConnectionEntryName = this.jarURLConnection.getEntryName();

            if (jarEntryName.startsWith(jarConnectionEntryName)) {
                this.copyJarEntry(jarEntry, destination);
            }

        }

    }

    private String getFileName(final JarEntry jarEntry) {
        final String jarEntryName = jarEntry.getName();
        final String connectionEntryName = this.jarURLConnection.getEntryName();

        return jarEntryName.startsWith(connectionEntryName) ? jarEntryName.substring(connectionEntryName.length())
                : jarEntryName;
    }

    private void copyJarEntry(final JarEntry jarEntry, File destinationDirectory) {
        final String fileName = this.getFileName(jarEntry);
        final File currentFile = new File(destinationDirectory, fileName);

        if (jarEntry.isDirectory()) {
            currentFile.mkdirs();
        } else {
            try (OutputStream out = FileUtils.openOutputStream(currentFile);
                    InputStream is = this.jarFile.getInputStream(jarEntry)) {
                IOUtils.copy(is, out);
            } catch (Exception e) {

            }
        }

    }

}