SchedulerNotifyInputStream


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17  
18  
19  package org.apache.james.util;
20  
21  import org.apache.avalon.cornerstone.services.scheduler.TimeScheduler;
22  
23  import java.io.IOException  ;
24  import java.io.InputStream  ;
25  
26  /**
27   * This will reset the scheduler each time a certain amount of data has
28   * been transfered.  This allows us to keep the timeout settings low, while
29   * not timing out during large data transfers.
30   */
31  public class SchedulerNotifyInputStream extends InputStream   {
32  
33      /**
34       * The wrapped InputStream
35       */
36      InputStream   in = null;
37  
38      /**
39       * The scheduler managing the trigger to be reset by this stream
40       */
41      TimeScheduler scheduler = null;
42  
43      /**
44       * The name of the trigger
45       */
46      String   triggerName = null;
47  
48      /**
49       * The number of bytes that need to be read before the counter is reset.
50       */
51      int lengthReset = 0;
52  
53      /**
54       * The number of bytes read since the counter was last reset
55       */
56      int readCounter = 0;
57  
58      /**
59       * @param in the InputStream to be wrapped by this stream
60       * @param scheduler the TimeScheduler managing the trigger to be reset by this stream
61       * @param triggerName the name of the particular trigger to be reset by this stream
62       * @param lengthReset the number of bytes to be read in between trigger resets
63       */
64      public SchedulerNotifyInputStream(InputStream   in,
65              TimeScheduler scheduler, String   triggerName, int lengthReset) {
66          this.in = in;
67          this.scheduler = scheduler;
68          this.triggerName = triggerName;
69          this.lengthReset = lengthReset;
70  
71          readCounter = 0;
72      }
73  
74      /**
75       * Read an array of bytes from the stream
76       *
77       * @param b the array of bytes to read from the stream
78       * @param off the index in the array where we start writing
79       * @param len the number of bytes of the array to read
80       *
81       * @return the number of bytes read
82       *
83       * @throws IOException if an exception is encountered when reading
84       */
85      public int read(byte[] b, int off, int len) throws IOException   {
86          int l = in.read(b, off, len);
87          readCounter += l;
88  
89          if (readCounter > lengthReset) {
90              readCounter -= lengthReset;
91              scheduler.resetTrigger(triggerName);
92          }
93  
94          return l;
95      }
96  
97      /**
98       * Read a byte from the stream
99       *
100      * @return the byte read from the stream
101      * @throws IOException if an exception is encountered when reading
102      */
103     public int read() throws IOException   {
104         int b = in.read();
105         readCounter++;
106 
107         if (readCounter > lengthReset) {
108             readCounter -= lengthReset;
109             scheduler.resetTrigger(triggerName);
110         }
111 
112         return b;
113     }
114 
115     /**
116      * Close the stream
117      *
118      * @throws IOException if an exception is encountered when closing
119      */
120     public void close() throws IOException   {
121         in.close();
122     }
123 }
124
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