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4  *
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8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
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11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
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25 
26 package com.sun.jndi.ldap;
27 
28 import java.io.IOException;
29 import java.util.concurrent.BlockingQueue;
30 import java.util.concurrent.LinkedBlockingQueue;
31 import javax.naming.CommunicationException;
32 
33 final class LdapRequest {
34 
35     LdapRequest next;   // Set/read in synchronized Connection methods
36     int msgId;          // read-only
37 
38     private int gotten = 0;
39     private BlockingQueue<BerDecoder> replies;
40     private int highWatermark = -1;
41     private boolean cancelled = false;
42     private boolean pauseAfterReceipt = false;
43     private boolean completed = false;
44 
LdapRequest(int msgId, boolean pause)45     LdapRequest(int msgId, boolean pause) {
46         this(msgId, pause, -1);
47     }
48 
LdapRequest(int msgId, boolean pause, int replyQueueCapacity)49     LdapRequest(int msgId, boolean pause, int replyQueueCapacity) {
50         this.msgId = msgId;
51         this.pauseAfterReceipt = pause;
52         if (replyQueueCapacity == -1) {
53             this.replies = new LinkedBlockingQueue<BerDecoder>();
54         } else {
55             this.replies =
56                 new LinkedBlockingQueue<BerDecoder>(replyQueueCapacity);
57             highWatermark = (replyQueueCapacity * 80) / 100; // 80% capacity
58         }
59     }
60 
cancel()61     synchronized void cancel() {
62         cancelled = true;
63 
64         // Unblock reader of pending request
65         // Should only ever have at most one waiter
66         notify();
67     }
68 
addReplyBer(BerDecoder ber)69     synchronized boolean addReplyBer(BerDecoder ber) {
70         if (cancelled) {
71             return false;
72         }
73 
74         // Add a new reply to the queue of unprocessed replies.
75         try {
76             replies.put(ber);
77         } catch (InterruptedException e) {
78             // ignore
79         }
80 
81         // peek at the BER buffer to check if it is a SearchResultDone PDU
82         try {
83             ber.parseSeq(null);
84             ber.parseInt();
85             completed = (ber.peekByte() == LdapClient.LDAP_REP_RESULT);
86         } catch (IOException e) {
87             // ignore
88         }
89         ber.reset();
90 
91         notify(); // notify anyone waiting for reply
92         /*
93          * If a queue capacity has been set then trigger a pause when the
94          * queue has filled to 80% capacity. Later, when the queue has drained
95          * then the reader gets unpaused.
96          */
97         if (highWatermark != -1 && replies.size() >= highWatermark) {
98             return true; // trigger the pause
99         }
100         return pauseAfterReceipt;
101     }
102 
getReplyBer()103     synchronized BerDecoder getReplyBer() throws CommunicationException {
104         if (cancelled) {
105             throw new CommunicationException("Request: " + msgId +
106                 " cancelled");
107         }
108 
109         /*
110          * Remove a reply if the queue is not empty.
111          * poll returns null if queue is empty.
112          */
113         BerDecoder reply = replies.poll();
114         return reply;
115     }
116 
hasSearchCompleted()117     synchronized boolean hasSearchCompleted() {
118         return completed;
119     }
120 }
121