Source for java.awt.event.InvocationEvent

   1: /* InvocationEvent.java -- call a runnable when dispatched
   2:    Copyright (C) 1999, 2002, 2004, 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 java.awt.event;
  40: 
  41: import java.awt.AWTEvent;
  42: import java.awt.ActiveEvent;
  43: import java.awt.EventQueue;
  44: 
  45: /**
  46:  * This event executes {@link Runnable#run()} of a target object when it is
  47:  * dispatched. This class is used by calls to <code>invokeLater</code> and
  48:  * <code>invokeAndWait</code>, so client code can use this fact to avoid
  49:  * writing special-casing AWTEventListener objects.
  50:  *
  51:  * @author Aaron M. Renn (arenn@urbanophile.com)
  52:  * @see ActiveEvent
  53:  * @see EventQueue#invokeLater(Runnable)
  54:  * @see EventQueue#invokeAndWait(Runnable)
  55:  * @see AWTEventListener
  56:  * @since 1.2
  57:  * @status updated to 1.4
  58:  */
  59: public class InvocationEvent extends AWTEvent implements ActiveEvent
  60: {
  61:   /**
  62:    * Compatible with JDK 1.2+.
  63:    */
  64:   private static final long serialVersionUID = 436056344909459450L;
  65: 
  66:   /** This is the first id in the range of event ids used by this class. */
  67:   public static final int INVOCATION_FIRST = 1200;
  68: 
  69:   /** This is the default id for this event type. */
  70:   public static final int INVOCATION_DEFAULT = 1200;
  71: 
  72:   /** This is the last id in the range of event ids used by this class. */
  73:   public static final int INVOCATION_LAST = 1200;
  74: 
  75:   /**
  76:    * This is the <code>Runnable</code> object to call when dispatched.
  77:    *
  78:    * @serial the runnable to execute
  79:    */
  80:   protected Runnable runnable;
  81: 
  82:   /**
  83:    * This is the object to call <code>notifyAll()</code> on when
  84:    * the call to <code>run()</code> returns, or <code>null</code> if no
  85:    * object is to be notified.
  86:    *
  87:    * @serial the object to notify
  88:    */
  89:   protected Object notifier;
  90: 
  91:   /**
  92:    * This variable is set to <code>true</code> if exceptions are caught
  93:    * and stored in a variable during the call to <code>run()</code>, otherwise
  94:    * exceptions are ignored and propagate up.
  95:    *
  96:    * @serial true to catch exceptions
  97:    */
  98:   protected boolean catchExceptions;
  99: 
 100:   /**
 101:    * This is the caught exception thrown in the <code>run()</code> method. It
 102:    * is null if exceptions are ignored, the run method hasn't completed, or
 103:    * there were no exceptions.
 104:    *
 105:    * @serial the caught exception, if any
 106:    */
 107:   private Exception exception;
 108: 
 109:   /**
 110:    * This is the caught Throwable thrown in the <code>run()</code> method.
 111:    * It is null if throwables are ignored, the run method hasn't completed, 
 112:    * or there were no throwables thrown.
 113:    */
 114:   private Throwable throwable;
 115:   
 116:   /**
 117:    * The timestamp when this event was created.
 118:    *
 119:    * @see #getWhen()
 120:    * @serial the timestamp
 121:    * @since 1.4
 122:    */
 123:   private final long when = EventQueue.getMostRecentEventTime();
 124: 
 125:   /**
 126:    * Initializes a new instance of <code>InvocationEvent</code> with the
 127:    * specified source and runnable.
 128:    *
 129:    * @param source the source of the event
 130:    * @param runnable the <code>Runnable</code> object to invoke
 131:    * @throws IllegalArgumentException if source is null
 132:    */
 133:   public InvocationEvent(Object source, Runnable runnable)
 134:   {
 135:     this(source, INVOCATION_DEFAULT, runnable, null, false);
 136:   }
 137: 
 138:   /**
 139:    * Initializes a new instance of <code>InvocationEvent</code> with the
 140:    * specified source, runnable, and notifier.  It will also catch exceptions
 141:    * if specified. If notifier is non-null, this will call notifyAll() on
 142:    * the object when the runnable is complete. If catchExceptions is true,
 143:    * this traps any exception in the runnable, otherwise it lets the exception
 144:    * propagate up the Event Dispatch thread.
 145:    *
 146:    * @param source the source of the event
 147:    * @param runnable the <code>Runnable</code> object to invoke
 148:    * @param notifier the object to notify, or null
 149:    * @param catchExceptions true to catch exceptions from the runnable
 150:    */
 151:   public InvocationEvent(Object source, Runnable runnable, Object notifier,
 152:                          boolean catchExceptions)
 153:   {
 154:     this(source, INVOCATION_DEFAULT, runnable, notifier, catchExceptions);
 155:   }
 156: 
 157:   /**
 158:    * Initializes a new instance of <code>InvocationEvent</code> with the
 159:    * specified source, runnable, and notifier.  It will also catch exceptions
 160:    * if specified. If notifier is non-null, this will call notifyAll() on
 161:    * the object when the runnable is complete. If catchExceptions is true,
 162:    * this traps any exception in the runnable, otherwise it lets the exception
 163:    * propagate up the Event Dispatch thread. Note that an invalid id leads to
 164:    * unspecified results.
 165:    *
 166:    * @param source the source of the event
 167:    * @param id the event id
 168:    * @param runnable the <code>Runnable</code> object to invoke
 169:    * @param notifier the object to notify, or null
 170:    * @param catchExceptions true to catch exceptions from the runnable
 171:    */
 172:   protected InvocationEvent(Object source, int id, Runnable runnable,
 173:                             Object notifier, boolean catchExceptions)
 174:   {
 175:     super(source, id);
 176:     this.runnable = runnable;
 177:     this.notifier = notifier;
 178:     this.catchExceptions = catchExceptions;
 179:   }
 180: 
 181:   /**
 182:    * This method calls the <code>run()</code> method of the runnable, traps
 183:    * exceptions if instructed to do so, and calls <code>notifyAll()</code>
 184:    * on any notifier if all worked successfully.
 185:    */
 186:   public void dispatch()
 187:   {
 188:     if (catchExceptions)
 189:       try
 190:         {
 191:           runnable.run();
 192:         }
 193:       catch (Throwable t)
 194:         {
 195:           throwable = t;
 196:           if (t instanceof Exception)
 197:             exception = (Exception)t;
 198:         }
 199:     else
 200:       runnable.run();
 201: 
 202:     Object o = notifier;
 203:     if (o != null)
 204:       synchronized(o)
 205:     {
 206:       o.notifyAll();
 207:     }
 208:   }
 209: 
 210:   /**
 211:    * This method returns the exception that occurred during the execution of
 212:    * the runnable, or <code>null</code> if not exception was thrown or
 213:    * exceptions were not caught.
 214:    *
 215:    * @return the exception thrown by the runnable
 216:    */
 217:   public Exception getException()
 218:   {
 219:     return exception;
 220:   }
 221: 
 222:   /**
 223:    * Returns a throwable caught while executing the Runnable's run() method.
 224:    * Null if none was thrown or if this InvocationEvent doesn't catch
 225:    * throwables.
 226:    * @return the caught Throwable
 227:    * @since 1.5
 228:    */
 229:   public Throwable getThrowable()
 230:   {
 231:     return throwable;
 232:   }
 233:   
 234:   /**
 235:    * Gets the timestamp of when this event was created.
 236:    *
 237:    * @return the timestamp of this event
 238:    * @since 1.4
 239:    */
 240:   public long getWhen()
 241:   {
 242:     return when;
 243:   }
 244: 
 245:   /**
 246:    * This method returns a string identifying this event. This is formatted as:
 247:    * <code>"INVOCATION_DEFAULT,runnable=" + runnable + ",notifier=" + notifier
 248:    * + ",catchExceptions=" + catchExceptions + ",when=" + getWhen()</code>.
 249:    *
 250:    * @return a string identifying this event
 251:    */
 252:   public String paramString()
 253:   {
 254:     return (id == INVOCATION_DEFAULT ? "INVOCATION_DEFAULT,runnable="
 255:             : "unknown type,runnable=") + runnable + ",notifier=" + notifier
 256:       + ",catchExceptions=" + catchExceptions + ",when=" + when;
 257:   }
 258: } // class InvocationEvent