001: /*
002: * Copyright (C) 1999-2004 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</a>
003: *
004: * This library is free software; you can redistribute it and/or
005: * modify it under the terms of the GNU Lesser General Public
006: * License as published by the Free Software Foundation; either
007: * version 2 of the License, or (at your option) any later version.
008: *
009: * This library is distributed in the hope that it will be useful,
010: * but WITHOUT ANY WARRANTY; without even the implied warranty of
011: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012: * Lesser General Public License for more details.
013: *
014: * You should have received a copy of the GNU Lesser General Public
015: * License along with this library; if not, write to the Free Software
016: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
017: */
018: package org.mandarax.kernel;
019:
020: import java.util.Iterator;
021: import java.util.Vector;
022:
023: import org.mandarax.util.logging.*;
024:
025: /**
026: * Abstract super class providing some common functionality
027: * for classes implementing <code>org.mandarax.kernel.Clause</code>.
028: * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
029: * @version 3.4 <7 March 05>
030: * @since 1.0
031: */
032: public abstract class AbstractClause extends AbstractPropertiesSupport
033: implements Clause, LogCategories {
034:
035: protected transient Vector clauseSetChangeListener = new Vector();
036: protected ClauseSet container = this ;
037:
038: /**
039: * Constructor.
040: */
041: public AbstractClause() {
042: super ();
043: }
044:
045: /**
046: * Add a clause set listener.
047: * @param l the listener
048: */
049: public void addClauseSetChangeListener(ClauseSetChangeListener l) {
050: clauseSetChangeListener.add(l);
051: }
052:
053: /**
054: * Get a clause iterator.
055: * @return a clause iterator
056: */
057: public org.mandarax.util.ClauseIterator clauses() {
058: return new org.mandarax.util.SingleClauseIterator(this );
059: }
060:
061: /**
062: * Get a clause iterator.
063: * @param query the query clause
064: * @param additionalParameter an optional additional parameter
065: * @return a clause iterator
066: */
067: public org.mandarax.util.ClauseIterator clauses(Clause query,
068: Object additionalParameter) {
069: return clauses();
070: }
071:
072: /**
073: * Fire a clause set change event.
074: * @param e the change event
075: */
076: protected void fireClauseSetChangeEvent(ClauseSetChangeEvent e) {
077: ClauseSetChangeListener l;
078: for (Iterator it = clauseSetChangeListener.iterator(); it
079: .hasNext();) {
080: l = (ClauseSetChangeListener) it.next();
081: l.clauseSetChanged(e);
082: }
083: }
084:
085: /**
086: * Get the clause set containing the clause. This method is in particular useful for analyzing derivations,
087: * since derivations show only the clauses used, not the clause set generating this clauses (e.g., AutoFacts). On the other
088: * hand, knowledge bases contain often clause sets. So it could be hard to find the clause sets in the knowledge base
089: * that caused a certain result. For sme clauses such as facts, the container is just the fact itself.
090: * @return a clause set
091: */
092: public ClauseSet getContainer() {
093: return container;
094: }
095:
096: /**
097: * Remove a clause set listener.
098: * @param l the listener
099: */
100: public void removeClauseSetChangeListener(ClauseSetChangeListener l) {
101: clauseSetChangeListener.remove(l);
102: }
103:
104: /**
105: * Set a container.
106: * @param aContainerthe new container
107: */
108: public void setContainer(ClauseSet aContainer) {
109: container = aContainer;
110: }
111: }
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