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1: /* SelectorProvider.java 2: Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package java.nio.channels.spi; 39: 40: import gnu.java.nio.SelectorProviderImpl; 41: 42: import java.io.IOException; 43: import java.nio.channels.DatagramChannel; 44: import java.nio.channels.Pipe; 45: import java.nio.channels.ServerSocketChannel; 46: import java.nio.channels.SocketChannel; 47: 48: 49: /** 50: * @author Michael Koch 51: * @since 1.4 52: */ 53: public abstract class SelectorProvider 54: { 55: private static SelectorProvider systemDefaultProvider; 56: 57: /** 58: * Initializes the selector provider. 59: * 60: * @exception SecurityException If a security manager has been installed and 61: * it denies @see RuntimePermission ("selectorProvider"). 62: */ 63: protected SelectorProvider() 64: { 65: SecurityManager sm = System.getSecurityManager(); 66: if (sm != null) 67: sm.checkPermission(new RuntimePermission("selectorProvider")); 68: } 69: 70: /** 71: * Opens a datagram channel. 72: * 73: * @return a new datagram channel object 74: * 75: * @exception IOException if an error occurs 76: */ 77: public abstract DatagramChannel openDatagramChannel() 78: throws IOException; 79: 80: /** 81: * Opens a pipe. 82: * 83: * @return a new pipe object 84: * 85: * @exception IOException if an error occurs 86: */ 87: public abstract Pipe openPipe() throws IOException; 88: 89: /** 90: * Opens a selector. 91: * 92: * @return a new selector object 93: * 94: * @exception IOException if an error occurs 95: */ 96: public abstract AbstractSelector openSelector() throws IOException; 97: 98: /** 99: * Opens a server socket channel. 100: * 101: * @return a new server socket channel object 102: * 103: * @exception IOException if an error occurs 104: */ 105: public abstract ServerSocketChannel openServerSocketChannel() 106: throws IOException; 107: 108: /** 109: * Opens a socket channel. 110: * 111: * @return a new socket channel object 112: * 113: * @exception IOException if an error occurs 114: */ 115: public abstract SocketChannel openSocketChannel() throws IOException; 116: 117: /** 118: * Returns the system-wide default selector provider for this invocation 119: * of the Java virtual machine. 120: * 121: * @return the default seletor provider 122: */ 123: public static synchronized SelectorProvider provider() 124: { 125: if (systemDefaultProvider == null) 126: { 127: String propertyValue = 128: System.getProperty("java.nio.channels.spi.SelectorProvider"); 129: 130: if (propertyValue == null || propertyValue.equals("")) 131: systemDefaultProvider = new SelectorProviderImpl(); 132: else 133: { 134: try 135: { 136: systemDefaultProvider = 137: (SelectorProvider) Class.forName(propertyValue) 138: .newInstance(); 139: } 140: catch (Exception e) 141: { 142: System.err.println("Could not instantiate class: " 143: + propertyValue); 144: systemDefaultProvider = new SelectorProviderImpl(); 145: } 146: } 147: } 148: 149: return systemDefaultProvider; 150: } 151: }