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1: /* Asynchron.java -- 2: Copyright (C) 2005 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: 39: package gnu.CORBA; 40: 41: import org.omg.CORBA.Request; 42: import org.omg.CORBA.WrongTransaction; 43: 44: import java.util.Iterator; 45: import java.util.LinkedList; 46: 47: /** 48: * Handles the asynchronous dynamic invocations. 49: * 50: * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org) 51: */ 52: public class Asynchron 53: { 54: LinkedList sent = new LinkedList(); 55: 56: /** 57: * Send multiple prepared requests one way, do not caring about the answer. 58: * The messages, containing requests, will be marked, indicating that 59: * the sender is not expecting to get a reply. 60: * 61: * @param requests the prepared array of requests. 62: * 63: * @see Request#send_oneway() 64: */ 65: public void send_multiple_requests_oneway(Request[] requests) 66: { 67: for (int i = 0; i < requests.length; i++) 68: { 69: requests [ i ].send_oneway(); 70: } 71: } 72: 73: /** 74: * Send multiple prepared requests expecting to get a reply. All requests 75: * are send in parallel, each in its own separate thread. When the 76: * reply arrives, it is stored in the agreed fields of the corresponing 77: * request data structure. If this method is called repeatedly, 78: * the new requests are added to the set of the currently sent requests, 79: * but the old set is not discarded. 80: * 81: * @param requests the prepared array of requests. 82: * 83: * @see #poll_next_response() 84: * @see #get_next_response() 85: * @see Request#send_deferred() 86: */ 87: public void send_multiple_requests_deferred(Request[] requests) 88: { 89: synchronized (sent) 90: { 91: for (int i = 0; i < requests.length; i++) 92: { 93: sent.add(requests [ i ]); 94: 95: // TODO Reuse threads that are instantiated in the method below, 96: // one thread per call. 97: requests [ i ].send_deferred(); 98: } 99: } 100: } 101: 102: /** 103: * Find if any of the requests that have been previously sent with 104: * {@link #send_multiple_requests_deferred}, have a response yet. 105: * 106: * @return true if there is at least one response to the previously 107: * sent request, false otherwise. 108: */ 109: public boolean poll_next_response() 110: { 111: synchronized (sent) 112: { 113: Iterator iter = sent.iterator(); 114: Request r; 115: while (iter.hasNext()) 116: { 117: r = (Request) iter.next(); 118: if (r.poll_response()) 119: return true; 120: } 121: } 122: return false; 123: } 124: 125: /** 126: * Get the next instance with a response being received. If all currently 127: * sent responses not yet processed, this method pauses till at least one of 128: * them is complete. If there are no requests currently sent, the method 129: * pauses till some request is submitted and the response is received. 130: * This strategy is identical to the one accepted by Suns 1.4 ORB 131: * implementation. 132: * 133: * The returned response is removed from the list of the currently 134: * submitted responses and is never returned again. 135: * 136: * @return the previously sent request that now contains the received 137: * response. 138: * 139: * @throws WrongTransaction If the method was called from the transaction 140: * scope different than the one, used to send the request. The exception 141: * can be raised only if the request is implicitly associated with some 142: * particular transaction. 143: */ 144: public Request get_next_response() 145: throws WrongTransaction 146: { 147: // The hard-coded waiting times for the incremental waiter. 148: // TODO it is possible to write more tricky system where the 149: // requests notify the Asynchron when they are complete. 150: // Wait for 5 ms intially. 151: int wait = 8; 152: 153: // Double the waiting time 154: int INC = 2; 155: 156: // Do not increase if the waiting time is already over 500 ms. 157: int MAX = 500; 158: while (true) 159: { 160: synchronized (sent) 161: { 162: Iterator iter = sent.iterator(); 163: Request r; 164: while (iter.hasNext()) 165: { 166: r = (Request) iter.next(); 167: if (r.poll_response()) 168: { 169: sent.remove(r); 170: return r; 171: } 172: } 173: } 174: try 175: { 176: Thread.sleep(wait); 177: if (wait < MAX) 178: wait = wait * INC; 179: } 180: catch (InterruptedException ex) 181: { 182: } 183: } 184: } 185: }