| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.xbean.classloader; |
| |
| import java.util.Enumeration; |
| import java.util.Iterator; |
| import java.util.Collection; |
| import java.util.NoSuchElementException; |
| |
| /** |
| * @version $Rev$ $Date$ |
| */ |
| public class ResourceEnumeration implements Enumeration { |
| private Iterator iterator; |
| private final String resourceName; |
| private Object next; |
| |
| public ResourceEnumeration(Collection resourceLocations, String resourceName) { |
| this.iterator = resourceLocations.iterator(); |
| this.resourceName = resourceName; |
| } |
| |
| public boolean hasMoreElements() { |
| fetchNext(); |
| return (next != null); |
| } |
| |
| public Object nextElement() { |
| fetchNext(); |
| |
| // save next into a local variable and clear the next field |
| Object next = this.next; |
| this.next = null; |
| |
| // if we didn't have a next throw an exception |
| if (next == null) { |
| throw new NoSuchElementException(); |
| } |
| return next; |
| } |
| |
| private void fetchNext() { |
| if (iterator == null) { |
| return; |
| } |
| if (next != null) { |
| return; |
| } |
| |
| try { |
| while (iterator.hasNext()) { |
| ResourceLocation resourceLocation = (ResourceLocation) iterator.next(); |
| ResourceHandle resourceHandle = resourceLocation.getResourceHandle(resourceName); |
| if (resourceHandle != null) { |
| next = resourceHandle.getUrl(); |
| return; |
| } |
| } |
| // no more elements |
| // clear the iterator so it can be GCed |
| iterator = null; |
| } catch (IllegalStateException e) { |
| // Jar file was closed... this means the resource finder was destroyed |
| // clear the iterator so it can be GCed |
| iterator = null; |
| throw e; |
| } |
| } |
| } |