bundles/org.simantics.databoard/src/org/simantics/databoard/accessor/impl/ListenerEntry.java

   1 /*******************************************************************************
   2  *  Copyright (c) 2010 Association for Decentralized Information Management in
   3  *  Industry THTH ry.
   4  *  All rights reserved. This program and the accompanying materials
   5  *  are made available under the terms of the Eclipse Public License v1.0
   6  *  which accompanies this distribution, and is available at
   7  *  http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  *  Contributors:
  10  *      VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.databoard.accessor.impl;
  13
  14 import java.util.Collection;
  15 import java.util.Collections;
  16 import java.util.concurrent.Executor;
  17
  18 import org.simantics.databoard.accessor.Accessor.Listener;
  19 import org.simantics.databoard.accessor.event.Event;
  20 import org.simantics.databoard.accessor.interestset.InterestSet;
  21 import org.simantics.databoard.accessor.reference.ChildReference;
  22
  23 /**
  24  * ListenerEntry is a linked list of <Listener, InterestSet> pairs
  25  *
  26  * @author Toni Kalajainen <toni.kalajainen@vtt.fi>
  27  */
  28 public class ListenerEntry {
  29
  30         public Listener listener;
  31         public InterestSet interestSet;
  32         // Path from the listened object
  33         public ChildReference path;
  34         public Executor executor;
  35         public ListenerEntry next;
  36
  37         public ListenerEntry(Listener listener, InterestSet interestSet, ChildReference path, Executor executor) {
  38                 if (interestSet==null) throw new IllegalArgumentException();
  39                 this.listener = listener;
  40                 this.interestSet = interestSet;
  41                 this.path = path;
  42                 this.executor = executor;
  43         }
  44
  45         /**
  46          * Add new entry to listener list
  47          *
  48          * @param prevValue
  49          * @param listener
  50          * @param interestSet
  51          * @return the new assignment for the list
  52          */
  53         public static ListenerEntry link(ListenerEntry prevValue, Listener listener, InterestSet interestSet, ChildReference path, Executor executor) {
  54                 ListenerEntry e = new ListenerEntry(listener, interestSet, path, executor);
  55                 e.next = prevValue;
  56                 return e;
  57         }
  58
  59         @SuppressWarnings("unchecked")
  60         public <T extends InterestSet> T getInterestSet() {
  61                 return (T) interestSet;
  62         }
  63
  64
  65         /**
  66          * Remove listener entry from linked list
  67          *
  68          * @param firstEntry
  69          * @param listener the value to be removed
  70          * @return the new assignment for the list
  71          */
  72         public static ListenerEntry remove(ListenerEntry firstEntry, Listener listener) {
  73                 ListenerEntry e = firstEntry;
  74                 ListenerEntry p = null;
  75                 while (e!=null) {
  76                         if (e.listener == listener) {
  77                                 if (p==null) return e.next;
  78                                 p.next = e.next;
  79                                 return firstEntry;
  80                         }
  81                         p = e;
  82                         e = e.next;
  83                 }
  84                 return null;
  85         }
  86
  87         /**
  88          * Emits an event to the listener.
  89          *
  90          * NOTE, Event instance can be emited only once. This method writes to the
  91          * e.reference field.
  92          *
  93          * @param e
  94          */
  95         public void emitEvent(final Event e) {
  96 //              e.reference = ChildReference.concatenate(path, e.reference);
  97                 if (executor == null) {
  98                         listener.onEvents( Collections.singleton(e) );
  99                 } else {
 100                         executor.execute( new Runnable() {
 101                                 public void run() {
 102                                         listener.onEvents( Collections.singleton(e) );
 103                                 }});
 104                 }
 105         }
 106
 107         public void emitEvents(final Collection<Event> events) {
 108 //              for (Event e : events) {
 109 //                      e.reference = ChildReference.concatenate(path, e.reference);
 110 //              }
 111                 if (executor == null) {
 112                         listener.onEvents( events );
 113                 } else {
 114                         executor.execute( new Runnable() {
 115                                 public void run() {
 116                                         listener.onEvents( events );
 117                                 }});
 118                 }
 119         }
 120
 121 }
 122