1/* 2 * Copyright (c) 2002, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package 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 */ 36final 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} 161