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1   /**
2    * Licensed to jclouds, Inc. (jclouds) under one or more
3    * contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  jclouds licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.jclouds.lifecycle;
20  
21  import java.io.Closeable;
22  import java.io.IOException;
23  import java.util.Collections;
24  import java.util.List;
25  
26  import javax.inject.Singleton;
27  
28  import com.google.common.collect.Lists;
29  
30  /**
31   * This will close objects in the reverse order that they were added.
32   * 
33   * @author Adrian Cole
34   */
35  @Singleton
36  public class Closer implements Closeable {
37     // guice is single threaded. no need to lock this
38     List<Closeable> methodsToClose = Lists.<Closeable> newArrayList();
39  
40     public void addToClose(Closeable toClose) {
41        methodsToClose.add(toClose);
42     }
43  
44     public void close() throws IOException {
45        Collections.reverse(methodsToClose);
46        for (Closeable toClose : methodsToClose) {
47           toClose.close();
48        }
49     }
50  }