reteoobuilder.java

jboss规则引擎

package org.drools.reteoo;

/*
 * 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.
 */

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.drools.InitialFact;
import org.drools.RuleIntegrationException;
import org.drools.base.ClassFieldExtractor;
import org.drools.base.ClassObjectType;
import org.drools.base.DroolsQuery;
import org.drools.base.EvaluatorFactory;
import org.drools.base.FieldFactory;
import org.drools.common.BetaNodeBinder;
import org.drools.common.InstanceEqualsConstraint;
import org.drools.common.InstanceNotEqualsConstraint;
import org.drools.rule.And;
import org.drools.rule.Column;
import org.drools.rule.Declaration;
import org.drools.rule.EvalCondition;
import org.drools.rule.Exists;
import org.drools.rule.GroupElement;
import org.drools.rule.InvalidPatternException;
import org.drools.rule.LiteralConstraint;
import org.drools.rule.Not;
import org.drools.rule.Query;
import org.drools.rule.Rule;
import org.drools.spi.Evaluator;
import org.drools.spi.FieldConstraint;
import org.drools.spi.FieldValue;
import org.drools.spi.ObjectTypeResolver;

/**
 * Builds the Rete-OO network for a <code>Package</code>.
 * 
 * @see org.drools.rule.Package
 * 
 * @author <a href="mailto:[e-mail]">Mark Proctor</a>
 * @author <a href="mailto:[e-mail]">Bob McWhirter</a>
 * 
 */
class ReteooBuilder
    implements
    Serializable {
    // ------------------------------------------------------------
    // Instance members
    // ------------------------------------------------------------

    /**
     * 
     */
    private static final long               serialVersionUID = 1737643968218792944L;

    /** The RuleBase */
    private transient ReteooRuleBase        ruleBase;

    /** Rete network to build against. */
    private transient Rete                  rete;

    private transient ReteooWorkingMemory[] workingMemories;

    private final ObjectTypeResolver        resolver;

    /** Nodes that have been attached. */
    private final Map                       attachedNodes;

    private TupleSource                     tupleSource;

    private ObjectSource                    objectSource;

    private Map                             declarations;

    private int                             id;

    private Map                             rules;

    private Map                             objectType;

    private int                             currentOffsetAdjustment;

    /** A factory for object sink lists */
    private transient ObjectSinkListFactory sinklistFactory;

    // ------------------------------------------------------------
    // Constructors
    // ------------------------------------------------------------

    /**
     * Construct a <code>Builder</code> against an existing <code>Rete</code>
     * network.
     */
    ReteooBuilder(final ReteooRuleBase ruleBase,
                  final ObjectTypeResolver resolver) {
        this.ruleBase = ruleBase;
        this.rete = this.ruleBase.getRete();
        this.resolver = resolver;
        this.attachedNodes = new HashMap();
        this.rules = new HashMap();

        //Set to 1 as Rete node is set to 0
        this.id = 1;

        // creating factory
        this.sinklistFactory = new ObjectSinkListFactory( this.ruleBase.getConfiguration() );
    }

    /**
     * Allow this to be settable, otherwise we get infinite recursion on serialisation
     * @param ruleBase
     */
    void setRuleBase(final ReteooRuleBase ruleBase) {
        this.ruleBase = ruleBase;
    }

    /**
     * Allow this to be settable, otherwise we get infinite recursion on serialisation
     * @param ruleBase
     */
    void setRete(final Rete rete) {

    }

    // ------------------------------------------------------------
    // Instance methods
    // ------------------------------------------------------------

    /**
     * Add a <code>Rule</code> to the network.
     * 
     * @param rule
     *            The rule to add.
     * 
     * @throws RuleIntegrationException
     *             if an error prevents complete construction of the network for
     *             the <code>Rule</code>.
     * @throws InvalidPatternException
     */
    void addRule(final Rule rule) throws InvalidPatternException {
        // reset working memories for potential propagation
        this.workingMemories = (ReteooWorkingMemory[]) this.ruleBase.getWorkingMemories().toArray( new ReteooWorkingMemory[this.ruleBase.getWorkingMemories().size()] );
        this.currentOffsetAdjustment = 0;

        final List nodes = new ArrayList();
        final And[] and = rule.getTransformedLhs();

        for ( int i = 0; i < and.length; i++ ) {
            if ( !hasColumns( and[i] ) ) {
                addInitialFactMatch( and[i] );
            }

            addRule( and[i],
                     rule );
            BaseNode node = null;
            if ( !(rule instanceof Query) ) {
                // Check a consequence is set
                if ( rule.getConsequence() == null ) {
                    throw new InvalidPatternException( "Rule '" + rule.getName() + "' has no Consequence" );
                }
                node = new TerminalNode( this.id++,
                                         this.tupleSource,
                                         rule );
            } else {
                // Check there is no consequence
                if ( rule.getConsequence() != null ) {
                    throw new InvalidPatternException( "Query '" + rule.getName() + "' should have no Consequence" );
                }
                node = new QueryTerminalNode( this.id++,
                                              this.tupleSource,
                                              rule );
            }

            nodes.add( node );

            if ( this.workingMemories.length == 0 ) {
                node.attach();
            } else {
                node.attach( this.workingMemories );
            }
        }

        this.rules.put( rule,
                        nodes.toArray( new BaseNode[nodes.size()] ) );
    }

    private boolean hasColumns(final GroupElement ge) {
        for ( final Iterator it = ge.getChildren().iterator(); it.hasNext(); ) {
            final Object object = it.next();
            if ( object instanceof Column || (object instanceof GroupElement && hasColumns( (GroupElement) object )) ) {
                return true;
            }
        }
        return false;
    }

    private void addInitialFactMatch(final And and) {
        And temp = null;

        // If we have children we know there are no columns but we need to make sure that InitialFact is first
        if ( !and.getChildren().isEmpty() ) {
            temp = (And) and.clone();
            and.getChildren().clear();
        }
        final Column column = new Column( 0,
                                          new ClassObjectType( InitialFact.class ) );
        and.addChild( column );

        // now we know InitialFact is first add all the previous constrains
        if ( temp != null ) {
            and.getChildren().addAll( temp.getChildren() );
        }
    }

    private void addRule(final And and,
                         final Rule rule) throws InvalidPatternException {
        this.objectSource = null;
        this.tupleSource = null;
        this.declarations = new HashMap();
        this.objectType = new LinkedHashMap();

        if ( rule instanceof Query ) {
            attachQuery( rule.getName() );
        }

        for ( final Iterator it = and.getChildren().iterator(); it.hasNext(); ) {
            final Object object = it.next();

            if ( object instanceof EvalCondition ) {
                final EvalCondition eval = (EvalCondition) object;
                checkUnboundDeclarations( eval.getRequiredDeclarations() );
                this.tupleSource = attachNode( new EvalConditionNode( this.id++,
                                                                      this.tupleSource,
                                                                      eval ) );
                continue;
            }

            BetaNodeBinder binder;
            Column column;

            if ( object instanceof Column ) {
                column = (Column) object;

                binder = attachColumn( (Column) object,
                                       and,
                                       true );

                // If a tupleSource does not exist then we need to adapt this
                // into
                // a TupleSource using LeftInputAdapterNode
                if ( this.tupleSource == null ) {
                    this.tupleSource = attachNode( new LeftInputAdapterNode( this.id++,
                                                                             this.objectSource,
                                                                             binder ) );

                    // objectSource is created by the attachColumn method, if we
                    // adapt this to
                    // a TupleSource then we need to null the objectSource
                    // reference.
                    this.objectSource = null;
                }
            } else {
                // If its not a Column or EvalCondition then it can either be a Not or an Exists
                GroupElement ce = (GroupElement) object;
                while ( !(ce.getChildren().get( 0 ) instanceof Column) ) {
                    ce = (GroupElement) ce.getChildren().get( 0 );
                }
                column = (Column) ce.getChildren().get( 0 );

                // If a tupleSource does not exist then we need to adapt an
                // InitialFact into a a TupleSource using LeftInputAdapterNode
                if ( this.tupleSource == null ) {
                    // adjusting offset as all tuples will now contain initial-fact at index 0
                    this.currentOffsetAdjustment = 1;

                    final ObjectSource objectSource = attachNode( new ObjectTypeNode( this.id++,
                                                                                      this.sinklistFactory.newObjectSinkList( ObjectTypeNode.class ),
                                                                                      new ClassObjectType( InitialFact.class ),
                                                                                      this.rete ) );

                    this.tupleSource = attachNode( new LeftInputAdapterNode( this.id++,
                                                                             objectSource ) );
                }

                binder = attachColumn( column,
                                       and,
                                       true );
            }

            if ( object instanceof Not ) {
                attachNot( this.tupleSource,
                           (Not) object,
                           this.objectSource,
                           binder,
                           column );
            } else if ( object instanceof Exists ) {
                attachExists( this.tupleSource,
                              (Exists) object,