PipelineCacheKey


1   /*
2    * Copyright 1999-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.cocoon.caching;
17  
18  import java.io.Serializable  ;
19  import java.util.ArrayList  ;
20  import java.util.List  ;
21  
22  /**
23   * This is the cache key for one pipeline (or the first part of a pipeline).
24   * It consists of one or more {@link ComponentCacheKey}s.
25   *
26   * @author <a HREF="mailto:cziegeler@apache.org">Carsten Ziegeler</a>
27   * @version CVS $Id: PipelineCacheKey.java 30932 2004-07-29 17:35:38Z vgritsenko $
28   */
29  public final class PipelineCacheKey
30          implements Serializable   {
31  
32      /** The keys */
33      private final List   keys;
34  
35      /** the hash code */
36      private int hashCode;
37  
38      /**
39       * Constructor
40       */
41      public PipelineCacheKey() {
42          this.keys = new ArrayList  (6);
43      }
44  
45      /**
46       * Constructor
47       */
48      public PipelineCacheKey(int size) {
49          this.keys = new ArrayList  (size);
50      }
51  
52      /**
53       * Add a key
54       */
55      public void addKey(ComponentCacheKey key) {
56          this.keys.add(key);
57          this.hashCode = 0;
58          this.toString = null;
59      }
60  
61      /**
62       * Remove the last key
63       */
64      public void removeLastKey() {
65          this.keys.remove(this.keys.size()-1);
66          this.hashCode = 0;
67          this.toString = null;
68      }
69  
70      /**
71       * Remove unitl cachepoint (including cachePoint) 
72       */
73      public void removeUntilCachePoint() {
74          this.hashCode = 0;
75          this.toString = null;
76          int keyCount = this.keys.size();
77  
78          while (keyCount > 0) {
79              if (((ComponentCacheKey)this.keys.get(keyCount-1)).isCachePoint()) {
80                  this.keys.remove(keyCount-1);
81                  return;
82              }
83              this.keys.remove(keyCount-1);
84              keyCount--;
85          }
86      }
87  
88      /**
89       * Return the number of keys
90       */
91      public int size() {
92          return this.keys.size();
93      }
94  
95      /**
96       * Compare
97       */
98      public boolean equals(Object   object) {
99          if (object instanceof PipelineCacheKey) {
100             PipelineCacheKey pck = (PipelineCacheKey)object;
101             final int len = this.keys.size();
102             if (pck.keys.size() == len) {
103                 boolean cont = true;
104                 int i = 0;
105                 while (i < len && cont) {
106                     cont = this.keys.get(i).equals(pck.keys.get(i));
107                     i++;
108                 }
109                 return cont;
110             }
111         }
112         return false;
113     }
114 
115     /**
116      * Generate a hash code
117      */
118     public int hashCode() {
119         if (this.hashCode == 0) {
120             final int len = this.keys.size();
121             for(int i=0; i < len; i++) {
122                 this.hashCode += this.keys.get(i).hashCode();
123             }
124             if (len % 2 == 0) this.hashCode++;
125         }
126         return this.hashCode;
127     }
128 
129     /**
130      * Clone the object (but not the component keys)
131      */
132     public PipelineCacheKey copy() {
133         final int len = this.keys.size();
134         PipelineCacheKey pck = new PipelineCacheKey(len);
135         for(int i=0; i < len; i++) {
136             pck.keys.add(this.keys.get(i));
137         }
138         return pck;
139     }
140 
141     private String   toString;
142 
143     /**
144      * toString
145      * The FilesystemStore uses toString!
146      */
147     public String   toString() {
148         if (this.toString == null) {
149             StringBuffer   buffer = new StringBuffer  ();
150             buffer.append("PK");
151             final int len = this.keys.size();
152             for(int i=0; i < len; i++) {
153                 buffer.append('_').append(this.keys.get(i).toString());
154             }
155             this.toString = buffer.toString();
156         }
157         return toString;
158     }
159 }
160
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