InMemoryStreamCache


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  /* $Id: InMemoryStreamCache.java 426576 2006-07-28 15:44:37Z jeremias $ */
19   
20  package org.apache.fop.pdf;
21  
22  import java.io.ByteArrayOutputStream  ;
23  import java.io.OutputStream  ;
24  import java.io.IOException  ;
25  
26  /**
27   * StreamCache implementation that uses temporary files rather than heap.
28   */
29  public class InMemoryStreamCache implements StreamCache {
30  
31      private int hintSize = -1;
32  
33      /**
34       * The current output stream.
35       */
36      private ByteArrayOutputStream   output;
37  
38      /**
39       * Creates a new InMemoryStreamCache.
40       */
41      public InMemoryStreamCache() {
42      }
43  
44      /**
45       * Creates a new InMemoryStreamCache.
46       * @param hintSize a hint about the approximate expected size of the buffer
47       */
48      public InMemoryStreamCache(int hintSize) {
49          this.hintSize = hintSize;
50      }
51  
52      /**
53       * Get the current OutputStream. Do not store it - it may change
54       * from call to call.
55       * @throws IOException if there is an error getting the output stream
56       * @return the output stream containing the data
57       */
58      public OutputStream   getOutputStream() throws IOException   {
59          if (output == null) {
60              if (this.hintSize <= 0) {
61                  output = new ByteArrayOutputStream  (512);
62              } else {
63                  output = new ByteArrayOutputStream  (this.hintSize);
64              }
65          }
66          return output;
67      }
68  
69      /**
70       * @see org.apache.fop.pdf.StreamCache#write(byte[])
71       */
72      public void write(byte[] data) throws IOException   {
73          getOutputStream().write(data);
74      }
75      
76      /**
77       * Outputs the cached bytes to the given stream.
78       * @param out the output stream to write to
79       * @return the number of bytes written
80       * @throws IOException if there is an IO error writing to the output stream
81       */
82      public int outputContents(OutputStream   out) throws IOException   {
83          if (output == null) {
84              return 0;
85          }
86  
87          output.writeTo(out);
88          return output.size();
89      }
90  
91      /**
92       * Returns the current size of the stream.
93       * @throws IOException if there is an error getting the size
94       * @return the length of the stream
95       */
96      public int getSize() throws IOException   {
97          if (output == null) {
98              return 0;
99          } else {
100             return output.size();
101         }
102     }
103 
104     /**
105      * Clears and resets the cache.
106      * @throws IOException if there is an error closing the stream
107      */
108     public void clear() throws IOException   {
109         if (output != null) {
110             output.close();
111             output = null;
112         }
113     }
114 }
115
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