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.resource.names; 018 019 import org.apache.commons.discovery.ResourceNameDiscover; 020 import org.apache.commons.discovery.ResourceNameIterator; 021 022 023 /** 024 * Helper class for methods implementing the ResourceNameDiscover interface. 025 * 026 * @author Richard A. Sitze 027 */ 028 public abstract class ResourceNameDiscoverImpl implements ResourceNameDiscover 029 { 030 /** 031 * Locate names of resources that are bound to <code>resourceName</code>. 032 * 033 * @return ResourceNameIterator 034 */ 035 public abstract ResourceNameIterator findResourceNames(String resourceName); 036 037 /** 038 * Locate names of resources that are bound to <code>resourceName</code>. 039 * 040 * @return ResourceNameIterator 041 */ 042 public ResourceNameIterator findResourceNames(final ResourceNameIterator inputNames) { 043 return new ResourceNameIterator() { 044 private ResourceNameIterator resourceNames = null; 045 private String resourceName = null; 046 047 public boolean hasNext() { 048 if (resourceName == null) { 049 resourceName = getNextResourceName(); 050 } 051 return resourceName != null; 052 } 053 054 public String nextResourceName() { 055 String name = resourceName; 056 resourceName = null; 057 return name; 058 } 059 060 private String getNextResourceName() { 061 while (inputNames.hasNext() && (resourceNames == null || !resourceNames.hasNext())) { 062 resourceNames = 063 findResourceNames(inputNames.nextResourceName()); 064 } 065 066 return (resourceNames != null && resourceNames.hasNext()) 067 ? resourceNames.nextResourceName() 068 : null; 069 } 070 }; 071 } 072 }