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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 org.apache.http.annotation.Contract;
30  import org.apache.http.annotation.ThreadingBehavior;
31  import org.apache.http.util.Args;
32  
33  import java.util.concurrent.TimeUnit;
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  @Contract(threading = ThreadingBehavior.SAFE_CONDITIONAL)
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 validityDeadline;
59  
60      private long updated;
61  
62      private long expiry;
63  
64      private volatile Object state;
65  
66      /**
67       * Creates new {@code PoolEntry} instance.
68       *
69       * @param id unique identifier of the pool entry. May be {@code null}.
70       * @param route route to the opposite endpoint.
71       * @param conn the connection.
72       * @param timeToLive maximum time to live. May be zero if the connection
73       *   does not have an expiry deadline.
74       * @param tunit time unit.
75       */
76      public PoolEntry(final String id, final T route, final C conn,
77              final long timeToLive, final TimeUnit tunit) {
78          super();
79          Args.notNull(route, "Route");
80          Args.notNull(conn, "Connection");
81          Args.notNull(tunit, "Time unit");
82          this.id = id;
83          this.route = route;
84          this.conn = conn;
85          this.created = System.currentTimeMillis();
86          this.updated = this.created;
87          if (timeToLive > 0) {
88              final long deadline = this.created + tunit.toMillis(timeToLive);
89              // If the above overflows then default to Long.MAX_VALUE
90              this.validityDeadline = deadline > 0 ? deadline : Long.MAX_VALUE;
91          } else {
92              this.validityDeadline = Long.MAX_VALUE;
93          }
94          this.expiry = this.validityDeadline;
95      }
96  
97      /**
98       * Creates new {@code PoolEntry} instance without an expiry deadline.
99       *
100      * @param id unique identifier of the pool entry. May be {@code null}.
101      * @param route route to the opposite endpoint.
102      * @param conn the connection.
103      */
104     public PoolEntry(final String id, final T route, final C conn) {
105         this(id, route, conn, 0, TimeUnit.MILLISECONDS);
106     }
107 
108     public String getId() {
109         return this.id;
110     }
111 
112     public T getRoute() {
113         return this.route;
114     }
115 
116     public C getConnection() {
117         return this.conn;
118     }
119 
120     public long getCreated() {
121         return this.created;
122     }
123 
124     /**
125      * @since 4.4
126      */
127     public long getValidityDeadline() {
128         return this.validityDeadline;
129     }
130 
131     /**
132      * @deprecated use {@link #getValidityDeadline()}
133      */
134     @Deprecated
135     public long getValidUnit() {
136         return this.validityDeadline;
137     }
138 
139     public Object getState() {
140         return this.state;
141     }
142 
143     public void setState(final Object state) {
144         this.state = state;
145     }
146 
147     public synchronized long getUpdated() {
148         return this.updated;
149     }
150 
151     public synchronized long getExpiry() {
152         return this.expiry;
153     }
154 
155     public synchronized void updateExpiry(final long time, final TimeUnit tunit) {
156         Args.notNull(tunit, "Time unit");
157         this.updated = System.currentTimeMillis();
158         final long newExpiry;
159         if (time > 0) {
160             newExpiry = this.updated + tunit.toMillis(time);
161         } else {
162             newExpiry = Long.MAX_VALUE;
163         }
164         this.expiry = Math.min(newExpiry, this.validityDeadline);
165     }
166 
167     public synchronized boolean isExpired(final long now) {
168         return now >= this.expiry;
169     }
170 
171     /**
172      * Invalidates the pool entry and closes the pooled connection associated
173      * with it.
174      */
175     public abstract void close();
176 
177     /**
178      * Returns {@code true} if the pool entry has been invalidated.
179      */
180     public abstract boolean isClosed();
181 
182     @Override
183     public String toString() {
184         final StringBuilder buffer = new StringBuilder();
185         buffer.append("[id:");
186         buffer.append(this.id);
187         buffer.append("][route:");
188         buffer.append(this.route);
189         buffer.append("][state:");
190         buffer.append(this.state);
191         buffer.append("]");
192         return buffer.toString();
193     }
194 
195 }