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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * 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   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.pool;
28  
29  import java.util.concurrent.TimeUnit;
30  
31  import org.apache.http.annotation.GuardedBy;
32  import org.apache.http.annotation.ThreadSafe;
33  import org.apache.http.util.Args;
34  
35  /**
36   * Pool entry containing a pool connection object along with its route.
37   * <p/>
38   * The connection contained by the pool entry may have an expiration time which
39   * can be either set upon construction time or updated with
40   * the {@link #updateExpiry(long, TimeUnit)}.
41   * <p/>
42   * Pool entry may also have an object associated with it that represents
43   * a connection state (usually a security principal or a unique token identifying
44   * the user whose credentials have been used while establishing the connection).
45   *
46   * @param <T> the route type that represents the opposite endpoint of a pooled
47   *   connection.
48   * @param <C> the connection type.
49   * @since 4.2
50   */
51  @ThreadSafe
52  public abstract class PoolEntry<T, C> {
53  
54      private final String id;
55      private final T route;
56      private final C conn;
57      private final long created;
58      private final long validUnit;
59  
60      @GuardedBy("this")
61      private long updated;
62  
63      @GuardedBy("this")
64      private long expiry;
65  
66      private volatile Object state;
67  
68      /**
69       * Creates new <tt>PoolEntry</tt> instance.
70       *
71       * @param id unique identifier of the pool entry. May be <code>null</code>.
72       * @param route route to the opposite endpoint.
73       * @param conn the connection.
74       * @param timeToLive maximum time to live. May be zero if the connection
75       *   does not have an expiry deadline.
76       * @param tunit time unit.
77       */
78      public PoolEntry(final String id, final T route, final C conn,
79              final long timeToLive, final TimeUnit tunit) {
80          super();
81          Args.notNull(route, "Route");
82          Args.notNull(conn, "Connection");
83          Args.notNull(tunit, "Time unit");
84          this.id = id;
85          this.route = route;
86          this.conn = conn;
87          this.created = System.currentTimeMillis();
88          if (timeToLive > 0) {
89              this.validUnit = this.created + tunit.toMillis(timeToLive);
90          } else {
91              this.validUnit = Long.MAX_VALUE;
92          }
93          this.expiry = this.validUnit;
94      }
95  
96      /**
97       * Creates new <tt>PoolEntry</tt> instance without an expiry deadline.
98       *
99       * @param id unique identifier of the pool entry. May be <code>null</code>.
100      * @param route route to the opposite endpoint.
101      * @param conn the connection.
102      */
103     public PoolEntry(final String id, final T route, final C conn) {
104         this(id, route, conn, 0, TimeUnit.MILLISECONDS);
105     }
106 
107     public String getId() {
108         return this.id;
109     }
110 
111     public T getRoute() {
112         return this.route;
113     }
114 
115     public C getConnection() {
116         return this.conn;
117     }
118 
119     public long getCreated() {
120         return this.created;
121     }
122 
123     public long getValidUnit() {
124         return this.validUnit;
125     }
126 
127     public Object getState() {
128         return this.state;
129     }
130 
131     public void setState(final Object state) {
132         this.state = state;
133     }
134 
135     public synchronized long getUpdated() {
136         return this.updated;
137     }
138 
139     public synchronized long getExpiry() {
140         return this.expiry;
141     }
142 
143     public synchronized void updateExpiry(final long time, final TimeUnit tunit) {
144         Args.notNull(tunit, "Time unit");
145         this.updated = System.currentTimeMillis();
146         final long newExpiry;
147         if (time > 0) {
148             newExpiry = this.updated + tunit.toMillis(time);
149         } else {
150             newExpiry = Long.MAX_VALUE;
151         }
152         this.expiry = Math.min(newExpiry, this.validUnit);
153     }
154 
155     public synchronized boolean isExpired(final long now) {
156         return now >= this.expiry;
157     }
158 
159     /**
160      * Invalidates the pool entry and closes the pooled connection associated
161      * with it.
162      */
163     public abstract void close();
164 
165     /**
166      * Returns <code>true</code> if the pool entry has been invalidated.
167      */
168     public abstract boolean isClosed();
169 
170     @Override
171     public String toString() {
172         final StringBuilder buffer = new StringBuilder();
173         buffer.append("[id:");
174         buffer.append(this.id);
175         buffer.append("][route:");
176         buffer.append(this.route);
177         buffer.append("][state:");
178         buffer.append(this.state);
179         buffer.append("]");
180         return buffer.toString();
181     }
182 
183 }