01 /*
02 *
03 * Licensed to the Apache Software Foundation (ASF) under one
04 * or more contributor license agreements. See the NOTICE file
05 * distributed with this work for additional information
06 * regarding copyright ownership. The ASF licenses this file
07 * to you under the Apache License, Version 2.0 (the
08 * "License"); you may not use this file except in compliance
09 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 *
20 */
21 package org.apache.qpid.server.flow;
22
23 import java.util.concurrent.atomic.AtomicBoolean;
24 import java.util.Set;
25 import java.util.HashSet;
26
27 public abstract class AbstractFlowCreditManager implements FlowCreditManager
28 {
29 protected final AtomicBoolean _suspended = new AtomicBoolean(false);
30 private final Set<FlowCreditManagerListener> _listeners = new HashSet<FlowCreditManagerListener>();
31
32 public final void addStateListener(FlowCreditManagerListener listener)
33 {
34 _listeners.add(listener);
35 }
36
37 public final boolean removeListener(FlowCreditManagerListener listener)
38 {
39 return _listeners.remove(listener);
40 }
41
42 private void notifyListeners(final boolean suspended)
43 {
44 for(FlowCreditManagerListener listener : _listeners)
45 {
46 listener.creditStateChanged(!suspended);
47 }
48 }
49
50 protected final void setSuspended(final boolean suspended)
51 {
52 if(_suspended.compareAndSet(!suspended, suspended))
53 {
54 notifyListeners(suspended);
55 }
56 }
57
58 protected final void notifyIncreaseBytesCredit()
59 {
60 notifyListeners(false);
61 }
62 }
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