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.resource.names;
018
019import org.apache.commons.discovery.ResourceNameDiscover;
020import org.apache.commons.discovery.ResourceNameIterator;
021import org.apache.commons.logging.Log;
022import org.apache.commons.logging.LogFactory;
023
024/**
025 * Recover resource name from System Properties.
026 */
027public class DiscoverNamesInSystemProperties extends ResourceNameDiscoverImpl implements ResourceNameDiscover {
028
029    private static Log log = LogFactory.getLog(DiscoverNamesInSystemProperties.class);
030
031    /**
032     * Sets the {@code Log} for this class.
033     *
034     * @param _log This class {@code Log}
035     * @deprecated This method is not thread-safe
036     */
037    @Deprecated
038    public static void setLog(Log _log) {
039        log = _log;
040    }
041
042    /**
043     * Construct a new resource discoverer
044     */
045    public DiscoverNamesInSystemProperties() {
046    }
047
048    /**
049     * {@inheritDoc}
050     */
051    @Override
052    public ResourceNameIterator findResourceNames(final String resourceName) {
053        if (log.isDebugEnabled()) {
054            log.debug("find: resourceName='" + resourceName + "'");
055        }
056
057        return new ResourceNameIterator() {
058
059            private String resource = System.getProperty(resourceName);
060
061            public boolean hasNext() {
062                return resource != null;
063            }
064
065            public String nextResourceName() {
066                String element = resource;
067                resource = null;
068                return element;
069            }
070        };
071    }
072
073}