001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.weaver;
020
021import java.io.File;
022import java.net.URLClassLoader;
023import java.util.ArrayList;
024import java.util.Collections;
025import java.util.LinkedHashSet;
026import java.util.List;
027import java.util.Properties;
028import java.util.ServiceLoader;
029import java.util.Set;
030import java.util.logging.Logger;
031
032import org.apache.commons.lang3.Validate;
033import org.apache.commons.weaver.model.WeaveEnvironment;
034import org.apache.commons.weaver.spi.Weaver;
035import org.apache.commons.weaver.utils.URLArray;
036import org.apache.xbean.finder.archive.FileArchive;
037
038/**
039 * This class discovers and invokes available {@link Weaver} plugins.
040 */
041public class WeaveProcessor {
042
043    private static final Logger LOG = Logger.getLogger(WeaveProcessor.class.getName());
044
045    /**
046     * List of picked up weaver plugins.
047     */
048    private static final List<Weaver> WEAVERS;
049
050    static {
051        final List<Weaver> weavers = new ArrayList<Weaver>();
052        for (final Weaver weaver : ServiceLoader.load(Weaver.class)) {
053            weavers.add(weaver);
054        }
055        WEAVERS = Collections.unmodifiableList(weavers);
056    }
057
058    /**
059     * The classpath which will be used to look up cross references during weaving.
060     */
061    private final List<String> classpath;
062
063    /**
064     * The actual path to be woven, replacing any affected classes.
065     */
066    private final File target;
067
068    /**
069     * Properties for configuring discovered plugin modules.
070     */
071    private final Properties configuration;
072
073    /**
074     * Create a new {@link WeaveProcessor} instance.
075     *
076     * @param classpath not {@code null}
077     * @param target not {@code null}
078     * @param configuration not {@code null}
079     */
080    public WeaveProcessor(final List<String> classpath, final File target, final Properties configuration) {
081        super();
082        this.classpath = Validate.notNull(classpath, "classpath");
083        this.target = Validate.notNull(target, "target");
084        Validate.isTrue(!target.exists() || target.isDirectory(), "%s is not a directory", target);
085        this.configuration = Validate.notNull(configuration, "configuration");
086    }
087
088    /**
089     * Weave classes in target directory.
090     */
091    public void weave() {
092        if (!target.exists()) {
093            LOG.warning("Target directory " + target + " does not exist; nothing to do!");
094        }
095        final Set<String> finderClasspath = new LinkedHashSet<String>();
096        finderClasspath.add(target.getAbsolutePath());
097        finderClasspath.addAll(classpath);
098        final ClassLoader classLoader = new URLClassLoader(URLArray.fromPaths(finderClasspath));
099        final Finder finder = new Finder(new FileArchive(classLoader, target));
100        for (final Weaver weaver : WEAVERS) {
101            final WeaveEnvironment env =
102                new LocalWeaveEnvironment(target, classLoader, configuration, Logger.getLogger(weaver.getClass()
103                    .getName()));
104            weaver.process(env, finder);
105        }
106    }
107}