1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF 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.apache.myfaces.view.facelets.pool.impl;
20
21 import java.util.Queue;
22 import java.util.concurrent.ConcurrentLinkedQueue;
23 import java.util.concurrent.atomic.AtomicInteger;
24 import org.apache.myfaces.view.facelets.pool.ViewEntry;
25
26 /**
27 * Fast pool using ConcurrentLinkedQueue, with uses an AtomicInteger as
28 * count limit. The reasons of design this pool in this way are:
29 *
30 * <ol>
31 * <li>There is no need to put a hard limit about the max number of views stored
32 * in the pool. Remember ViewEntry internally has a Soft or Weak reference over
33 * the view. The maxCount is just a way to limit the max footprint fo the pool
34 * in memory, but if the limit is exceed, the vm can always reclaim the memory space.</li>
35 * <li>View creation is quite fast, so according to previous tests done,
36 * include any syncronized method in this code will produce worse performance.</li>
37 * </ol>
38 *
39 * @author Leonardo Uribe
40 */
41 public class ViewPoolEntryHolder
42 {
43 private Queue<ViewEntry> queue;
44
45 private AtomicInteger count;
46
47 private int maxCount;
48
49 public ViewPoolEntryHolder(int maxCount)
50 {
51 this.queue = new ConcurrentLinkedQueue<ViewEntry>();
52 this.count = new AtomicInteger();
53 this.maxCount = maxCount;
54 }
55
56 public boolean add(ViewEntry entry)
57 {
58 if (count.get() < maxCount)
59 {
60 queue.add(entry);
61 count.incrementAndGet();
62 return true;
63 }
64 return false;
65 }
66
67 public ViewEntry poll()
68 {
69 ViewEntry entry = queue.poll();
70 count.decrementAndGet();
71 return entry;
72 }
73
74 public boolean isFull()
75 {
76 return count.get() >= maxCount;
77 }
78
79 public int getCount()
80 {
81 return count.get();
82 }
83 }