/**
 * Copyright (C) 2004-2008 Jive Software. All rights reserved.
 *
 * 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.jivesoftware.openfire.starter;

import java.io.File;
import java.io.FilenameFilter;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Arrays;

/**
 * A simple classloader to extend the classpath to
 * include all jars in a lib directory.<p>
 *
 * The new classpath includes all <tt>*.jar</tt> and <tt>*.zip</tt>
 * archives (zip is commonly used in packaging JDBC drivers). The extended
 * classpath is used for both the initial server startup, as well as loading
 * plug-in support jars.
 *
 * @author Derek DeMoro
 * @author Iain Shigeoka
 */
class JiveClassLoader extends URLClassLoader {

    /**
     * Constructs the classloader.
     *
     * @param parent the parent class loader (or null for none).
     * @param libDir the directory to load jar files from.
     * @throws java.net.MalformedURLException if the libDir path is not valid.
     */
    JiveClassLoader(ClassLoader parent, File libDir) throws MalformedURLException {
        super(new URL[] { libDir.toURI().toURL() }, parent);

        File[] jars = libDir.listFiles(new FilenameFilter() {
            @Override
            public boolean accept(File dir, String name) {
                boolean accept = false;
                String smallName = name.toLowerCase();
                if (smallName.endsWith(".jar")) {
                    accept = true;
                }
                else if (smallName.endsWith(".zip")) {
                    accept = true;
                }
                return accept;
            }
        });

        // Do nothing if no jar or zip files were found
        if (jars == null) {
            return;
        }

        // sort jars otherwise order differs between installations (e.g. it's not alphabetical)
        // order may matter if trying to patch an install by adding patch jar to lib folder
        Arrays.sort(jars);
        for (int i = 0; i < jars.length; i++) {
            if (jars[i].isFile()) {
                addURL(jars[i].toURI().toURL());
            }
        }
    }
}
