org.apache.xbean.classloader.JarFileUrlStreamHandler Maven / Gradle / Ivy

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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.xbean.classloader;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * @author Dain Sundstrom
 */
public class JarFileUrlStreamHandler extends URLStreamHandler {

	public static URL createUrl(JarFile jarFile, JarEntry jarEntry) throws MalformedURLException {
		return createUrl(jarFile, jarEntry, new File(jarFile.getName()).toURI().toURL());
	}

	public static URL createUrl(JarFile jarFile, JarEntry jarEntry, URL codeSource) throws MalformedURLException {
		JarFileUrlStreamHandler handler = new JarFileUrlStreamHandler(jarFile, jarEntry);
		URL url = new URL("jar", "", -1, codeSource + "!/" + jarEntry.getName(), handler);
		handler.setExpectedUrl(url);
		return url;
	}

	private URL expectedUrl;
	private final JarFile jarFile;
	private final JarEntry jarEntry;

	public JarFileUrlStreamHandler(JarFile jarFile, JarEntry jarEntry) {
		if (jarFile == null) {
			throw new IllegalArgumentException("Illegal null jarFile specified for JarFileUrlStreamHandler");
		}
		if (jarEntry == null) {
			throw new IllegalArgumentException("Illegal null jarEntry specified for JarFileUrlStreamHandler");
		}
		this.jarFile = jarFile;
		this.jarEntry = jarEntry;
	}

	public void setExpectedUrl(URL expectedUrl) {
		if (expectedUrl == null) {
			throw new IllegalArgumentException("Illegal null expectedUrl specified for setExpectedUrl");
		}
		this.expectedUrl = expectedUrl;
	}

	public URLConnection openConnection(URL url) throws IOException {
		if (expectedUrl == null) {
			throw new IllegalStateException("expectedUrl was not set");
		}

		// the caller copied the URL reusing a stream handler from a previous call
		if (!expectedUrl.equals(url)) {
			// the new url is supposed to be within our context, so it must have a jar protocol
			if (!url.getProtocol().equals("jar")) {
				throw new IllegalArgumentException("Unsupported protocol " + url.getProtocol());
			}

			// split the path at "!/" into the file part and entry part
			String path = url.getPath();
			String[] chunks = path.split("!/", 2);

			// if we only got only one chunk, it didn't contain the required "!/" delimiter
			if (chunks.length == 1) {
				throw new MalformedURLException("Url does not contain a '!' character: " + url);
			}

			String file = chunks[0];
			String entryPath = chunks[1];

			// this handler only supports jars on the local file system
			if (!file.startsWith("file:")) {
				// let the system handler deal with this
				return new URL(url.toExternalForm()).openConnection();
			}
			file = file.substring("file:".length());

			// again the new url is supposed to be within our context so it must reference the same jar file
			if (!jarFile.getName().equals(file)) {
				// let the system handler deal with this
				return new URL(url.toExternalForm()).openConnection();
			}

			// get the entry
			JarEntry newEntry = jarFile.getJarEntry(entryPath);
			if (newEntry == null) {
				throw new FileNotFoundException("Entry not found: " + url);
			}
			return new JarFileUrlConnection(url, jarFile, newEntry);
		}

		return new JarFileUrlConnection(url, jarFile, jarEntry);
	}
}