001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.discovery.ant;
018
019import java.util.LinkedList;
020import java.util.List;
021
022import org.apache.commons.discovery.ResourceNameIterator;
023import org.apache.commons.discovery.jdk.JDKHooks;
024import org.apache.commons.discovery.resource.DiscoverResources;
025
026/**
027 * Small ant task that will use discovery to locate a particular impl.
028 * and display all values.
029 *
030 * You can execute this and save it with an id, then other classes can use it.
031 */
032public class ServiceDiscoveryTask {
033
034    String name;
035
036    int debug=0;
037
038    String[] drivers = null;
039
040    /**
041     * Sets the service name has to be discovered.
042     *
043     * @param name The service name has to be discovered.
044     */
045    public void setServiceName(String name) {
046        this.name=name;
047    }
048
049    /**
050     * Sets the debug level.
051     *
052     * @param i The debug level
053     */
054    public void setDebug(int i) {
055        this.debug=i;
056    }
057
058    /**
059     * Returns the discovered SPIs name.
060     *
061     * @return The discovered SPIs name
062     */
063    public String[] getServiceInfo() {
064        return drivers;
065    }
066
067    /**
068     * Executes the Apache Ant task, discovering the set service name
069     *
070     * @throws Exception if any error occurs
071     */
072    public void execute() throws Exception {
073        System.out.printf("Discovering service '%s'...%n", name);
074
075        DiscoverResources disc = new DiscoverResources();
076        disc.addClassLoader( JDKHooks.getJDKHooks().getThreadContextClassLoader() );
077        disc.addClassLoader( this.getClass().getClassLoader() );
078
079        ResourceNameIterator iterator = disc.findResources(name);
080
081        List<String> resources = new LinkedList<String>();
082        while (iterator.hasNext()) {
083            String resourceInfo = iterator.nextResourceName();
084            resources.add(resourceInfo);
085            if (debug > 0) {
086                System.out.printf("Found '%s'%n", resourceInfo);
087            }
088        }
089
090        drivers = new String[resources.size()];
091        resources.toArray(drivers);
092    }
093
094}