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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software 
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License.
16   */
17  
18  package org.apache.jdo.impl.enhancer.util;
19  
20  import java.util.List;
21  import java.util.Iterator;
22  
23  import java.io.PrintWriter;
24  import java.io.InputStream;
25  
26  
27  
28  /***
29   * Searches resources among a set of files.
30   */
31  public class CombinedResourceLocator
32      extends ResourceLocatorBase
33      implements ResourceLocator
34  {
35      /***
36       * List of resource locators.
37       */
38      final List locators;
39  
40      /***
41       * Creates an intsance.
42       */
43      public CombinedResourceLocator(PrintWriter out,
44                                     boolean verbose,
45                                     List locators)
46      {
47          super(out, verbose);
48          affirm(locators != null);
49          this.locators = locators;
50      }
51      
52      /***
53       * Finds a resource with a given name.
54       */
55      public InputStream getInputStreamForResource(String resourceName)
56      {
57          affirm(resourceName != null);
58  
59          for (Iterator i = locators.iterator(); i.hasNext();) {
60              final ResourceLocator locator = (ResourceLocator)i.next();
61              affirm(locator != null);
62              final InputStream stream
63                  = locator.getInputStreamForResource(resourceName);
64              if (stream != null) {
65                  return stream;
66              }
67          }
68          return null;
69      }
70  }