J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2002 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.jndi.ldap.pool; |
| 27 | |
| 28 | /** |
| 29 | * Represents a description of PooledConnection in Connections. |
| 30 | * Contains a PooledConnection, its state (busy, idle, expired), and idle time. |
| 31 | * |
| 32 | * Any access or update to a descriptor's state is synchronized. |
| 33 | * |
| 34 | * @author Rosanna Lee |
| 35 | */ |
| 36 | final class ConnectionDesc { |
| 37 | private final static boolean debug = Pool.debug; |
| 38 | |
| 39 | // Package private because used by Pool.showStats() |
| 40 | static final byte BUSY = (byte)0; |
| 41 | static final byte IDLE = (byte)1; |
| 42 | static final byte EXPIRED = (byte)2; |
| 43 | |
| 44 | final private PooledConnection conn; |
| 45 | |
| 46 | private byte state = IDLE; // initial state |
| 47 | private long idleSince; |
| 48 | private long useCount = 0; // for stats & debugging only |
| 49 | |
| 50 | ConnectionDesc(PooledConnection conn) { |
| 51 | this.conn = conn; |
| 52 | } |
| 53 | |
| 54 | ConnectionDesc(PooledConnection conn, boolean use) { |
| 55 | this.conn = conn; |
| 56 | if (use) { |
| 57 | state = BUSY; |
| 58 | ++useCount; |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Two desc are equal if their PooledConnections are the same. |
| 64 | * This is useful when searching for a ConnectionDesc using only its |
| 65 | * PooledConnection. |
| 66 | */ |
| 67 | public boolean equals(Object obj) { |
| 68 | return obj != null |
| 69 | && obj instanceof ConnectionDesc |
| 70 | && ((ConnectionDesc)obj).conn == conn; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Hashcode is that of PooledConnection to facilitate |
| 75 | * searching for a ConnectionDesc using only its PooledConnection. |
| 76 | */ |
| 77 | public int hashCode() { |
| 78 | return conn.hashCode(); |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Changes the state of a ConnectionDesc from BUSY to IDLE and |
| 83 | * records the current time so that we will know how long it has been idle. |
| 84 | * @return true if state change occurred. |
| 85 | */ |
| 86 | synchronized boolean release() { |
| 87 | d("release()"); |
| 88 | if (state == BUSY) { |
| 89 | state = IDLE; |
| 90 | |
| 91 | idleSince = System.currentTimeMillis(); |
| 92 | return true; // Connection released, ready for reuse |
| 93 | } else { |
| 94 | return false; // Connection wasn't busy to begin with |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * If ConnectionDesc is IDLE, change its state to BUSY and return |
| 100 | * its connection. |
| 101 | * |
| 102 | * @return ConnectionDesc's PooledConnection if it was idle; null otherwise. |
| 103 | */ |
| 104 | synchronized PooledConnection tryUse() { |
| 105 | d("tryUse()"); |
| 106 | |
| 107 | if (state == IDLE) { |
| 108 | state = BUSY; |
| 109 | ++useCount; |
| 110 | return conn; |
| 111 | } |
| 112 | |
| 113 | return null; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * If ConnectionDesc is IDLE and has expired, close the corresponding |
| 118 | * PooledConnection. |
| 119 | * |
| 120 | * @param threshold a connection that has been idle before this time |
| 121 | * have expired. |
| 122 | * |
| 123 | * @return true if entry is idle and has expired; false otherwise. |
| 124 | */ |
| 125 | synchronized boolean expire(long threshold) { |
| 126 | if (state == IDLE && idleSince < threshold) { |
| 127 | |
| 128 | d("expire(): expired"); |
| 129 | |
| 130 | state = EXPIRED; |
| 131 | conn.closeConnection(); // Close real connection |
| 132 | |
| 133 | return true; // Expiration successful |
| 134 | } else { |
| 135 | d("expire(): not expired"); |
| 136 | return false; // Expiration did not occur |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | public String toString() { |
| 141 | return conn.toString() + " " + |
| 142 | (state == BUSY ? "busy" : (state == IDLE ? "idle" : "expired")); |
| 143 | } |
| 144 | |
| 145 | // Used by Pool.showStats() |
| 146 | int getState() { |
| 147 | return state; |
| 148 | } |
| 149 | |
| 150 | // Used by Pool.showStats() |
| 151 | long getUseCount() { |
| 152 | return useCount; |
| 153 | } |
| 154 | |
| 155 | private void d(String msg) { |
| 156 | if (debug) { |
| 157 | System.err.println("ConnectionDesc." + msg + " " + toString()); |
| 158 | } |
| 159 | } |
| 160 | } |