bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/prioritystack/PriorityStack.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in 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
  13 package org.simantics.utils.datastructures.prioritystack;
  14
  15 import java.lang.reflect.Array;
  16 import java.lang.reflect.Method;
  17 import java.util.ArrayList;
  18 import java.util.HashMap;
  19 import java.util.LinkedList;
  20 import java.util.List;
  21 import java.util.ListIterator;
  22 import java.util.Map;
  23
  24 import org.simantics.utils.strings.EString;
  25 import org.simantics.utils.threads.IThreadWorkQueue;
  26 import org.simantics.utils.threads.SyncListenerList;
  27
  28
  29 /**
  30  * Implementation to IPriorityStack.
  31  *
  32  * <p>
  33  * Note!
  34  * getAllItems() is optimized for result with the penalty of slower add/remove methods.
  35  *
  36  * @author Toni Kalajainen
  37  * @param <E>
  38  */
  39 public class PriorityStack<E> implements IPriorityStack<E> {
  40
  41         @SuppressWarnings({ "rawtypes" })
  42     private SyncListenerList<IPriorityStackListener> listeners =
  43                 new SyncListenerList<IPriorityStackListener>(IPriorityStackListener.class);
  44
  45         private LinkedList<E> list =
  46                 new LinkedList<E>();
  47
  48         private E[] snapshotArray;
  49
  50         private Map<E, Integer> priorities =
  51                 new HashMap<E, Integer>();
  52
  53         final Class<E> clazz;
  54
  55         public PriorityStack(Class<E> clazz) {
  56                 this.clazz = clazz;
  57                 snapshotArray = createArray(0);
  58         }
  59
  60         @Override
  61         public void add(E interactor, int priority) {
  62                 abu:
  63                 synchronized(this) {
  64                         if (list.contains(interactor))
  65                                 throw new IllegalArgumentException("InteractorStack already contains item "+interactor);
  66
  67                         priorities.put(interactor, priority);
  68
  69                         if (list.size()==0)
  70                         {
  71                                 list.add(interactor);
  72                                 snapshotArray = createSnapshot(list);
  73                                 break abu;
  74                         }
  75
  76                         ListIterator<E> li = list.listIterator();
  77                         while (li.hasNext()) {
  78                                 E i = li.next();
  79                                 double w = priorities.get( i );
  80                                 if (w > priority) {
  81                                         li.previous();
  82                                         li.add(interactor);
  83                                         snapshotArray = createSnapshot(list);
  84                                         break abu;
  85                                 }
  86                         }
  87                         list.addLast(interactor);
  88                         snapshotArray = createSnapshot(list);
  89                 }
  90                 fireInteractorAdded(interactor);
  91         }
  92
  93         @Override
  94         public boolean remove(E interactor) {
  95                 synchronized(this) {
  96                         if (!priorities.containsKey(interactor))
  97                                 return false;
  98                         priorities.remove(interactor);
  99                         list.remove(interactor);
 100                         snapshotArray = createSnapshot(list);
 101                 }
 102                 fireInteractorRemoved(interactor);
 103                 return true;
 104         }
 105
 106         @Override
 107         public synchronized Integer getPriority(E interactor) {
 108                 return priorities.get(interactor);
 109         }
 110
 111         @SuppressWarnings({ "unchecked" })
 112         private E[] createArray(int length)
 113         {
 114                 return (E[]) Array.newInstance(clazz, length);
 115         }
 116
 117         E[] createSnapshot(List<E> list) {
 118                 E[] result = createArray(list.size());
 119                 int index = 0;
 120                 for (E i : list)
 121                         result[index++] = i;
 122                 return result;
 123         }
 124
 125         public synchronized int indexOf(E item)
 126         {
 127                 for (int i=0; i<snapshotArray.length; i++)
 128                         if (snapshotArray[i]==item)
 129                                 return i;
 130                 return -1;
 131         }
 132
 133         @Override
 134         public synchronized E[] toArray() {
 135                 return snapshotArray;
 136         }
 137
 138         public synchronized <R extends E> R getSingleItem(Class<R> clazz)
 139         {
 140                 R array[] = getItemsByClass(clazz);
 141                 if (array.length!=1)
 142                         throw new RuntimeException("one "+clazz.getName()+" expected in PriorityStack, got "+array.length);
 143                 return (R) array[0];
 144         }
 145
 146         @SuppressWarnings("unchecked")
 147     @Override
 148         public synchronized <R extends E> R[] getItemsByClass(Class<R> clazz)
 149         {
 150                 List<E> result = new ArrayList<E>(list.size());
 151                 for (E i : list)
 152                         if (clazz.isAssignableFrom(i.getClass()))
 153                                 result.add(i);
 154                 return (R[])result.toArray(createArray(result.size()));
 155         }
 156
 157         private static Method itemAdded = SyncListenerList.getMethod(IPriorityStackListener.class, "itemAdded");
 158         private void fireInteractorAdded(E interactor)
 159         {
 160                 listeners.fireEventSync(itemAdded, this, interactor);
 161         }
 162
 163         private static Method itemRemoved = SyncListenerList.getMethod(IPriorityStackListener.class, "itemRemoved");
 164         private void fireInteractorRemoved(E interactor)
 165         {
 166                 listeners.fireEventSync(itemRemoved, this, interactor);
 167         }
 168
 169         @Override
 170         public synchronized void addStackListener(IPriorityStackListener<E> listener) {
 171                 listeners.add(listener);
 172         }
 173
 174         @Override
 175         public synchronized void removeStackListener(IPriorityStackListener<E> listener) {
 176                 listeners.remove(listener);
 177         }
 178
 179         @Override
 180         public synchronized boolean contains(E interactor) {
 181                 return list.contains(interactor);
 182         }
 183
 184         @Override
 185         public void addStackListener(IThreadWorkQueue thread,
 186                         IPriorityStackListener<E> listener) {
 187                 listeners.add(thread, listener);
 188         }
 189
 190         @Override
 191         public void removeStackListener(IThreadWorkQueue thread,
 192                         IPriorityStackListener<E> listener) {
 193                 listeners.remove(thread, listener);
 194         }
 195
 196         @Override
 197         public String toString() {
 198             return EString.implode(snapshotArray, "\n");
 199         }
 200
 201 }