bdi4jade

diff --git a/bdi-jade/src/bdi4jade/belief/DerivedBelief.java b/bdi-jade/src/bdi4jade/belief/DerivedBelief.java
new file mode 100644
index 0000000..68c9c76
--- /dev/null
+++ b/bdi-jade/src/bdi4jade/belief/DerivedBelief.java
@@ -0,0 +1,146 @@
+//----------------------------------------------------------------------------
+// Copyright (C) 2011  Ingrid Nunes
+// 
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// 
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+// 
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+// 
+// To contact the authors:
+// http://inf.ufrgs.br/prosoft/bdi4jade/
+//
+//----------------------------------------------------------------------------
+
+package bdi4jade.belief;
+
+/**
+ * This class represents a belief whose value is derived from other beliefs of a
+ * belief base. As a belief may be part of many belief bases, a main belief base
+ * is associated with this belief. The evaluation of the value of this belief is
+ * performed considering the belief of the main belief base.
+ * 
+ * @author Ingrid Nunes
+ */
+public abstract class DerivedBelief<K, V> extends AbstractBelief<K, V> {
+
+	private static final long serialVersionUID = 6923761036847007160L;
+
+	private BeliefBase mainBeliefBase;
+
+	/**
+	 * The default constructor. It should be only used if persistence frameworks
+	 * are used.
+	 */
+	public DerivedBelief() {
+		super();
+	}
+
+	/**
+	 * Creates a new derived belief. The value of this belief cannot be set as
+	 * it is derived from other values of a belief base.
+	 * 
+	 * @param name
+	 *            the belief name.
+	 */
+	public DerivedBelief(K name) {
+		super(name);
+	}
+
+	/**
+	 * Adds a belief base with which this belief is associated. If the main
+	 * belief base of this belief is null, it sets the given belief base as the
+	 * main belief base of this belief.
+	 * 
+	 * @see bdi4jade.belief.AbstractBelief#addBeliefBase(bdi4jade.belief.BeliefBase)
+	 */
+	@Override
+	public void addBeliefBase(BeliefBase beliefBase) {
+		if (mainBeliefBase == null) {
+			this.mainBeliefBase = beliefBase;
+		}
+		super.addBeliefBase(beliefBase);
+	}
+
+	/**
+	 * Evaluates the value of this belief, which is derived from beliefs of the
+	 * main belief base associated with this belief.
+	 * 
+	 * @return the value of this belief.
+	 */
+	protected abstract V evaluate();
+
+	/**
+	 * Returns the main belief base of this belief.
+	 * 
+	 * @return the main belief base.
+	 */
+	public BeliefBase getMainBeliefBase() {
+		return mainBeliefBase;
+	}
+
+	/**
+	 * Returns the value of this belief. If the main belief base is null, it
+	 * returns null. Otherwise, the method {@link #evaluate()} is invoked.
+	 * 
+	 * @return the value of this belief.
+	 * 
+	 * @see bdi4jade.belief.Belief#getValue()
+	 */
+	@Override
+	public V getValue() {
+		if (mainBeliefBase == null)
+			return null;
+		return evaluate();
+
+	}
+
+	/**
+	 * Removes a belief base associated with this belief. If the belief base was
+	 * the main belief base of this belief, this method sets a random belief
+	 * base from the belief bases associated with this belief as the main belief
+	 * base. If the removed belief base was the last belief base associated with
+	 * this belief, the main belief base is set to null.
+	 * 
+	 * @see bdi4jade.belief.AbstractBelief#removeBeliefBase(bdi4jade.belief.BeliefBase)
+	 */
+	@Override
+	public void removeBeliefBase(BeliefBase beliefBase) {
+		super.removeBeliefBase(beliefBase);
+		if (beliefBase.equals(mainBeliefBase)) {
+			this.mainBeliefBase = getBeliefBases().isEmpty() ? null
+					: getBeliefBases().iterator().next();
+		}
+	}
+
+	/**
+	 * Sets the main belief base of this belief. This method does not verify if
+	 * the main belief base is one of the belief bases associated with this
+	 * belief.
+	 * 
+	 * @param mainBeliefBase
+	 *            the main belief base to set.
+	 */
+	public void setMainBeliefBase(BeliefBase mainBeliefBase) {
+		this.mainBeliefBase = mainBeliefBase;
+	}
+
+	/**
+	 * This method throws a {@link NullPointerException}, as this operation is
+	 * invalid for this belief. The value of this belief cannot be set as it is
+	 * derived from other beliefs.
+	 */
+	@Override
+	protected void updateValue(V value) {
+		throw new NullPointerException("Invalid operation.");
+	}
+
+}
\ No newline at end of file

diff --git a/bdi-jade/src/bdi4jade/belief/DerivedPredicate.java b/bdi-jade/src/bdi4jade/belief/DerivedPredicate.java
new file mode 100644
index 0000000..a7491f0
--- /dev/null
+++ b/bdi-jade/src/bdi4jade/belief/DerivedPredicate.java
@@ -0,0 +1,56 @@
+//----------------------------------------------------------------------------
+// Copyright (C) 2011  Ingrid Nunes
+// 
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// 
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+// 
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+// 
+// To contact the authors:
+// http://inf.ufrgs.br/prosoft/bdi4jade/
+//
+//----------------------------------------------------------------------------
+
+package bdi4jade.belief;
+
+/**
+ * This class represents a logic predicate that is derived from other agent
+ * belief. The evaluation of this predicate is not given, but derived from other
+ * values of a belief base.
+ * 
+ * @author Ingrid Nunes
+ */
+public abstract class DerivedPredicate<K> extends DerivedBelief<K, Boolean>
+		implements Predicate<K> {
+
+	private static final long serialVersionUID = -1551397656846999182L;
+
+	/**
+	 * The default constructor. It should be only used if persistence frameworks
+	 * are used.
+	 */
+	public DerivedPredicate() {
+		super();
+	}
+
+	/**
+	 * Creates a new derived predicate. The value of this belief cannot be set
+	 * as it is derived from other values of a belief base.
+	 * 
+	 * @param name
+	 *            the belief name.
+	 */
+	public DerivedPredicate(K name) {
+		super(name);
+	}
+
+}