src/org/apache/xalan/xsltc/compiler/LocationPathPattern.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
/*
 * $Id$
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xml.dtm.Axis;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 */
public abstract class LocationPathPattern extends Pattern {
    private Template _template;
    private int _importPrecedence;
    private double _priority = Double.NaN;
    private int _position = 0;

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	return Type.Void;		// TODO
    }

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	// TODO: What does it mean to translate a Pattern ?
    }
	
    public void setTemplate(final Template template) {
	_template = template;
	_priority = template.getPriority();
	_importPrecedence = template.getImportPrecedence();
	_position = template.getPosition();
    }
		
    public Template getTemplate() {
	return _template;
    }
		
    public final double getPriority() {
	return Double.isNaN(_priority) ? getDefaultPriority() : _priority;
    }
		
    public double getDefaultPriority() {
	return 0.5;
    }

    /**
     * This method is used by the Mode class to prioritise patterns and
     * template. This method is called for templates that are in the same
     * mode and that match on the same core pattern. The rules used are:
     *  o) first check precedence - highest precedence wins
     *  o) then check priority - highest priority wins
     *  o) then check the position - the template that occured last wins
     */
    public boolean noSmallerThan(LocationPathPattern other) {
	if (_importPrecedence > other._importPrecedence) {
	    return true;
	}
	else if (_importPrecedence == other._importPrecedence) {
	    if (_priority > other._priority) {
		return true;
	    }
	    else if (_priority == other._priority) {
		if (_position > other._position) {
		    return true;
		}
	    }
	}
	return false;
    }
    
    public abstract StepPattern getKernelPattern();
	
    public abstract void reduceKernelPattern();
		
    public abstract boolean isWildcard();

    public int getAxis() {
	final StepPattern sp = getKernelPattern();
	return (sp != null) ? sp.getAxis() : Axis.CHILD;
    }

    public String toString() {
	return "root()";
    }
}