001: package org.zilonis.scope;
002:
003: /**
004: * Copyright (c) 2005 Elie Levy <elie.levy@zilonis.org>
005: * All rights reserved
006: *
007: * This License governs use of the accompanying Software, and your use of the
008: * Software constitutes acceptance of this license.
009: *
010: * You may use this Software for any non-commercial purpose, subject to the
011: * restrictions in this license. Some purposes which can be non-commercial are
012: * teaching, academic research, and personal experimentation. You may also
013: * distribute this Software with books or other teaching materials, or publish
014: * the Software on websites, that are intended to teach the use of the
015: * Software.
016: *
017: *
018: * You may not use or distribute this Software or any derivative works in any
019: * form for commercial purposes. Examples of commercial purposes would be
020: * running business operations, licensing, leasing, or selling the Software, or
021: * distributing the Software for use with commercial products.
022: *
023: * You may modify this Software and distribute the modified Software for
024: * non-commercial purposes, however, you may not grant rights to the Software
025: * or derivative works that are broader than those provided by this License.
026: * For example, you may not distribute modifications of the Software under
027: * terms that would permit commercial use, or under terms that purport to
028: * require the Software or derivative works to be sublicensed to others.
029: *
030: * You may use any information in intangible form that you remember after
031: * accessing the Software. However, this right does not grant you a license to
032: * any of the copyrights or patents for anything you might create using such
033: * information.
034: *
035: * In return, we simply require that you agree:
036: *
037: * Not to remove any copyright or other notices from the Software.
038: *
039: *
040: * That if you distribute the Software in source or object form, you will
041: * include a verbatim copy of this license.
042: *
043: *
044: * That if you distribute derivative works of the Software in source code form
045: * you do so only under a license that includes all of the provisions of this
046: * License, and if you distribute derivative works of the Software solely in
047: * object form you do so only under a license that complies with this License.
048: *
049: *
050: * That if you have modified the Software or created derivative works, and
051: * distribute such modifications or derivative works, you will cause the
052: * modified files to carry prominent notices so that recipients know that they
053: * are not receiving the original Software. Such notices must state: (i) that
054: * you have changed the Software; and (ii) the date of any changes.
055: *
056: *
057: * THAT THE SOFTWARE COMES "AS IS", WITH NO WARRANTIES. THIS MEANS NO EXPRESS,
058: * IMPLIED OR STATUTORY WARRANTY, INCLUDING WITHOUT LIMITATION, WARRANTIES OF
059: * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR ANY WARRANTY OF TITLE
060: * OR NON-INFRINGEMENT. ALSO, YOU MUST PASS THIS DISCLAIMER ON WHENEVER YOU
061: * DISTRIBUTE THE SOFTWARE OR DERIVATIVE WORKS.
062: *
063: *
064: * THAT NEITHER ZILONIS NOR THE AUTHOR WILL BE LIABLE FOR ANY DAMAGES RELATED
065: * TO THE SOFTWARE OR THIS LICENSE, INCLUDING DIRECT, INDIRECT, SPECIAL,
066: * CONSEQUENTIAL OR INCIDENTAL DAMAGES, TO THE MAXIMUM EXTENT THE LAW PERMITS,
067: * NO MATTER WHAT LEGAL THEORY IT IS BASED ON. ALSO, YOU MUST PASS THIS
068: * LIMITATION OF LIABILITY ON WHENEVER YOU DISTRIBUTE THE SOFTWARE OR
069: * DERIVATIVE WORKS.
070: *
071: *
072: * That if you sue anyone over patents that you think may apply to the Software
073: * or anyone's use of the Software, your license to the Software ends
074: * automatically.
075: *
076: *
077: * That your rights under the License end automatically if you breach it in any
078: * way.
079: *
080: *
081: * Elie Levy reserves all rights not expressly granted to you in this
082: * license.
083: *
084: */
085:
086: import java.util.LinkedList;
087: import java.util.concurrent.locks.ReentrantReadWriteLock;
088: import java.util.Iterator;
089: import org.zilonis.util.MultiList;
090: import org.zilonis.network.WME;
091:
092: public class Scope {
093:
094: private ReentrantReadWriteLock lock;
095:
096: private Scope parent;
097:
098: private LinkedList<Scope> children;
099:
100: private int level;
101:
102: private long lastId;
103:
104: private MultiList wmeInScope;
105:
106: public final static Scope ROOT = new Scope();
107:
108: private Scope(Scope parent) {
109: this ();
110: this .parent = parent;
111: level = parent.getLevel() + 1;
112: getReadLock();
113: parent.addChild(this );
114: releaseReadLock();
115: }
116:
117: private Scope() {
118: children = new LinkedList<Scope>();
119: lock = new ReentrantReadWriteLock();
120: wmeInScope = new MultiList(WME.SCOPE);
121: }
122:
123: public Iterator<WME> getWMEIterator() {
124: return wmeInScope.iterator();
125: }
126:
127: public void addWME(WME wme) {
128: wmeInScope.add(wme);
129: }
130:
131: public void terminate() {
132: wmeInScope.removeAll();
133: }
134:
135: public Scope getParent() {
136: return parent;
137: }
138:
139: public synchronized long getNextId() {
140: return lastId++;
141: }
142:
143: public LinkedList<Scope> getChildren() {
144: return children;
145: }
146:
147: public int getLevel() {
148: return level;
149: }
150:
151: public int compareTo(Scope scope) {
152: return level - scope.getLevel();
153: }
154:
155: public Scope createChild() {
156: return new Scope(this );
157: }
158:
159: private void addChild(Scope child) {
160: children.add(child);
161: }
162:
163: public void lock() {
164: if (parent != null)
165: parent.getReadLock();
166: getWriteLock();
167: }
168:
169: public void unlock() {
170: if (parent != null)
171: parent.releaseReadLock();
172: releaseWriteLocks();
173: }
174:
175: private void releaseReadLock() {
176: if (parent != null)
177: parent.releaseReadLock();
178: lock.readLock().unlock();
179: }
180:
181: private void releaseWriteLocks() {
182: lock.writeLock().unlock();
183: for (Scope child : children)
184: child.releaseWriteLocks();
185: }
186:
187: private void getReadLock() {
188: if (parent != null)
189: parent.getReadLock();
190: lock.readLock().lock();
191: }
192:
193: private void getWriteLock() {
194: lock.writeLock().lock();
195: for (Scope child : children)
196: child.getWriteLock();
197: }
198:
199: }
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