org.springframework.extensions.config.source.JarConfigSource.java Source code

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Here is the source code for org.springframework.extensions.config.source.JarConfigSource.java

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/**
 * Copyright (C) 2005-2009 Alfresco Software Limited.
 *
 * This file is part of the Spring Surf Extension project.
 *
 * 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 org.springframework.extensions.config.source;

import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Collections;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * ConfigSource implementation that gets its data via a file within a JAR file.
 * <p>
 * The location passed to the constructor should be in the default url format
 * for referencing a file in a JAR file i.e. jar:file:/c:\lib\file.jar!/META-INF/web-client-config-custom.xml
 * </p>
 * 
 * @author gavinc
 */
public class JarConfigSource extends BaseConfigSource {
    public static final String JAR_PROTOCOL = "jar";
    public static final String JAR_PATH_SEPARATOR = "!/";

    private static final Log logger = LogFactory.getLog(JarConfigSource.class);

    /**
     * Constructs a JarConfigSource
     * 
     * @param location The location of the file within a JAR
     */
    public JarConfigSource(String location) {
        super(Collections.singletonList(location));
    }

    @Override
    protected InputStream getInputStream(String sourceString) {
        InputStream in = null;

        try {
            // make sure the source string is valid
            if (sourceString.startsWith(JAR_PROTOCOL) == false) {
                throw new IllegalArgumentException("sourceString must start with \"" + JAR_PROTOCOL + ":\"");
            }

            int indexSep = sourceString.indexOf(JAR_PATH_SEPARATOR);
            if (indexSep == -1) {
                throw new IllegalArgumentException(
                        "sourceString must contain an entry within the JAR file i.e. jar:file:/[file]!/[entry]");
            }

            // extract the entry part from source string
            String entryStr = sourceString.substring(indexSep + JAR_PATH_SEPARATOR.length());

            // open the JAR file
            URL url = new URL(sourceString);
            URLConnection conn = url.openConnection();
            if (conn instanceof JarURLConnection) {
                // open the jar file, if it does not contain the entry requested a FileNotFound exception
                // is thrown and reported below
                JarFile jar = ((JarURLConnection) conn).getJarFile();
                ZipEntry entry = jar.getEntry(entryStr);
                if (entry != null) {
                    in = jar.getInputStream(entry);
                }
            }
        } catch (Exception e) {
            if (logger.isDebugEnabled())
                logger.debug("Failed to obtain input stream to URL: " + sourceString, e);
        }

        return in;
    }
}