org.eclipse.viatra2.gtasm.patternmatcher.impl/src/org/eclipse/viatra2/gtasm/patternmatcher/impl/patternmatcher/internal/SearchPlan.java

/*******************************************************************************
 * Copyright (c) 2004-2008 Akos Horvath, Gergely Varro and Daniel Varro
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Akos Horvath, Gergely Varro - initial API and implementation
 *******************************************************************************/

 package org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal;


import org.eclipse.viatra2.gtasm.patternmatcher.exceptions.PatternMatcherRuntimeException;
import org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal.operation.SearchPlanOperation;
import org.eclipse.viatra2.logger.Logger;

/**
 * A SearchPlan is an unmodifiable array of 
 * SearchPlanOperations. PatternSignatures are supposed
 * to be fixed 
 */
public class SearchPlan {
	private SearchPlanOperation[] operations;
    private int currentOperation;
	
	public SearchPlan(SearchPlanOperation[] operations){
		this.operations = operations;
        this.currentOperation = -1;
	}
    
    private void init(MatchingFrame frame) 
        throws PatternMatcherRuntimeException {
        if (currentOperation == -1) {
            currentOperation++;
            operations[currentOperation].preprocess(frame);
        } else if (currentOperation == operations.length - 1) {
            currentOperation--;
        } else {
        	String[] context = {frame.getPattern().getParent().getPattern().getName()};
            throw new PatternMatcherRuntimeException(
            		PatternMatcherErrorStrings.INTERNAL_SEARCHPLAN_INIT_FAILED
            		,context
            		,frame.getPattern().getParent().getPattern());
        }
    }
	
	/**
     * Calculates the cost of the search plan.
	 */
	public double cost() {
		/* default generated stub */;
		return 0.0;
	}

    public boolean execute(MatchingFrame frame) 
        throws PatternMatcherRuntimeException {
        int upperBound = operations.length - 1;
        //try {
            init(frame);
            while (currentOperation >= 0 && currentOperation < upperBound) {
                if (operations[currentOperation].execute(frame)) {
                    currentOperation++;
                    operations[currentOperation].preprocess(frame);
                } else {
                    operations[currentOperation].postprocess(frame);
                    currentOperation--;
                }
            }
        //TODO: additional stack trace information can be added if needed at this point (LS search plan execution)
        //} catch (PatternMatcherRuntimeException e) {
        //e.addNewStackElement(operations[currentOperation].getErrorfulElement(frame));
        //    throw e;
        //}
        return (currentOperation == upperBound);
    }
    
    public void printDebugInformation(Logger logger) {
        for (int i = 0; i < operations.length; i++) {
            logger.debug("[" + i + "]\t" + operations[i].toString());
        }
    }
}