/**
* Copyright 2005 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.drools.rule;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import org.drools.common.InternalFactHandle;
import org.drools.common.InternalWorkingMemory;
import org.drools.reteoo.LeftTuple;
import org.drools.spi.AcceptsReadAccessor;
import org.drools.spi.Evaluator;
import org.drools.spi.FieldValue;
import org.drools.spi.InternalReadAccessor;
import org.drools.spi.Restriction;
public class LiteralRestriction
implements
Restriction,
AcceptsReadAccessor,
Externalizable {
private static final long serialVersionUID = 510l;
private FieldValue field;
private Evaluator evaluator;
private InternalReadAccessor readAccessor;
private static final Declaration[] requiredDeclarations = new Declaration[0];
public LiteralRestriction() {
this( null,
null,
null );
}
public LiteralRestriction(final FieldValue field,
final Evaluator evaluator,
final InternalReadAccessor fieldExtractor) {
this.field = field;
this.evaluator = evaluator;
this.readAccessor = fieldExtractor;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
field = (FieldValue) in.readObject();
evaluator = (Evaluator) in.readObject();
readAccessor = (InternalReadAccessor) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( field );
out.writeObject( evaluator );
out.writeObject( readAccessor );
}
public void setReadAccessor(InternalReadAccessor readAccessor) {
this.readAccessor = readAccessor;
}
public Evaluator getEvaluator() {
return this.evaluator;
}
public FieldValue getField() {
return this.field;
}
public boolean isAllowed(final InternalReadAccessor readAccessor,
final InternalFactHandle handle,
final InternalWorkingMemory workingMemory,
final ContextEntry context) {
return this.evaluator.evaluate( workingMemory,
this.readAccessor,
handle.getObject(),
this.field );
}
public boolean isAllowedCachedLeft(final ContextEntry context,
final InternalFactHandle handle) {
return this.evaluator.evaluate( ((LiteralContextEntry)context).workingMemory,
((LiteralContextEntry) context).getFieldExtractor(),
handle.getObject(),
this.field );
}
public boolean isAllowedCachedRight(final LeftTuple tuple,
final ContextEntry context) {
return this.evaluator.evaluate( ((LiteralContextEntry)context).workingMemory,
((LiteralContextEntry) context).getFieldExtractor(),
((LiteralContextEntry) context).getObject(),
this.field );
}
/**
* Literal constraints cannot have required declarations, so always return an empty array.
* @return
* Return an empty <code>Declaration[]</code>
*/
public Declaration[] getRequiredDeclarations() {
return LiteralRestriction.requiredDeclarations;
}
public void replaceDeclaration(Declaration oldDecl,
Declaration newDecl) {
}
public boolean isTemporal() {
return evaluator.isTemporal();
}
public String toString() {
return "[LiteralRestriction evaluator=" + this.evaluator + " value=" + this.field + "]";
}
public int hashCode() {
final int PRIME = 31;
int result = 1;
result = PRIME * result + this.evaluator.hashCode();
result = PRIME * result + ((this.field.getValue() != null) ? this.field.getValue().hashCode() : 0);
return result;
}
public boolean equals(final Object object) {
if ( this == object ) {
return true;
}
if ( object == null || object.getClass() != LiteralRestriction.class ) {
return false;
}
final LiteralRestriction other = (LiteralRestriction) object;
return this.field.equals( other.field ) && this.evaluator.equals( other.evaluator );
}
public ContextEntry createContextEntry() {
return new LiteralContextEntry( this.readAccessor );
}
public Object clone() {
return new LiteralRestriction( this.field,
this.evaluator,
this.readAccessor );
}
private static class LiteralContextEntry
implements
ContextEntry {
private static final long serialVersionUID = 510l;
public InternalReadAccessor extractor;
public Object object;
public ContextEntry next;
public InternalWorkingMemory workingMemory;
public LiteralContextEntry() {
}
public LiteralContextEntry(final InternalReadAccessor extractor) {
this.extractor = extractor;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
extractor = (InternalReadAccessor) in.readObject();
object = in.readObject();
next = (ContextEntry) in.readObject();
workingMemory = ( InternalWorkingMemory ) in .readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( extractor );
out.writeObject( object );
out.writeObject( next );
out.writeObject( workingMemory );
}
public InternalReadAccessor getFieldExtractor() {
return this.extractor;
}
public Object getObject() {
return this.object;
}
public ContextEntry getNext() {
return this.next;
}
public void setNext(final ContextEntry entry) {
this.next = entry;
}
public void updateFromFactHandle(final InternalWorkingMemory workingMemory,
final InternalFactHandle handle) {
this.object = handle.getObject();
this.workingMemory = workingMemory;
}
public void updateFromTuple(final InternalWorkingMemory workingMemory,
final LeftTuple tuple) {
this.workingMemory = workingMemory;
}
public void resetTuple() {
}
public void resetFactHandle() {
this.object = null;
}
}
}