org.apache.xalan.xsltc.compiler.AbsoluteLocationPath Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of xalan Show documentation

Xalan-Java is an XSLT processor for transforming XML documents into HTML, text, or other XML document types. It implements XSL Transformations (XSLT) Version 1.0 and XML Path Language (XPath) Version 1.0 and can be used from the command line, in an applet or a servlet, or as a module in other program.

There is a newer version: 2.7.3

Show newest version

/*
 * 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: AbsoluteLocationPath.java 468650 2006-10-28 07:03:30Z minchau $
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKESPECIAL;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.NEW;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.NodeType;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
final class AbsoluteLocationPath extends Expression {
    private Expression _path;	// may be null 

    public AbsoluteLocationPath() {
	_path = null;
    }

    public AbsoluteLocationPath(Expression path) {
	_path = path;
	if (path != null) {
	    _path.setParent(this);
	}
    }

    public void setParser(Parser parser) {
	super.setParser(parser);
	if (_path != null) {
	    _path.setParser(parser);
	}
    }

    public Expression getPath() {
	return(_path);
    }
    
    public String toString() {
	return "AbsoluteLocationPath(" +
	    (_path != null ? _path.toString() : "null") + ')';
    }
	
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (_path != null) {
	    final Type ptype = _path.typeCheck(stable);
	    if (ptype instanceof NodeType) {		// promote to node-set
		_path = new CastExpr(_path, Type.NodeSet);
	    }
	}
	return _type = Type.NodeSet;	
    }
	
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();
	if (_path != null) {
	    final int initAI = cpg.addMethodref(ABSOLUTE_ITERATOR,
						"",
						"("
						+ NODE_ITERATOR_SIG
						+ ")V");

	    // Compile relative path iterator(s)
            //
            // Backwards branches are prohibited if an uninitialized object is
            // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed.
            // We don't know whether this code might contain backwards branches,
            // so we mustn't create the new object until after we've created
            // this argument to its constructor.  Instead we calculate the
            // value of the argument to the constructor first, store it in
            // a temporary variable, create the object and reload the argument
            // from the temporary to avoid the problem.
	    _path.translate(classGen, methodGen);
            LocalVariableGen relPathIterator
                    = methodGen.addLocalVariable("abs_location_path_tmp",
                                       Util.getJCRefType(NODE_ITERATOR_SIG),
                                       null, null);
            relPathIterator.setStart(
                    il.append(new ASTORE(relPathIterator.getIndex())));

	    // Create new AbsoluteIterator
	    il.append(new NEW(cpg.addClass(ABSOLUTE_ITERATOR)));
	    il.append(DUP);
            relPathIterator.setEnd(
                    il.append(new ALOAD(relPathIterator.getIndex())));

	    // Initialize AbsoluteIterator with iterator from the stack
	    il.append(new INVOKESPECIAL(initAI));
	}
	else {
	    final int gitr = cpg.addInterfaceMethodref(DOM_INTF,
						       "getIterator",
						       "()"+NODE_ITERATOR_SIG);
	    il.append(methodGen.loadDOM());
	    il.append(new INVOKEINTERFACE(gitr, 1));
	}
    }
}