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     */
017    package org.apache.commons.discovery.ant;
018    
019    import java.util.LinkedList;
020    import java.util.List;
021    
022    import org.apache.commons.discovery.ResourceNameIterator;
023    import org.apache.commons.discovery.jdk.JDKHooks;
024    import 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     */
032    public 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    }