/*
* @(#)$Id$
*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 2001, Sun
* Microsystems., http://www.sun.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
* @author Morten Jorgensen
*
*/
package org.apache.xalan.xsltc.compiler;
import java.util.Vector;
import java.util.Enumeration;
import org.apache.xalan.xsltc.compiler.util.Type;
import de.fub.bytecode.generic.*;
import org.apache.xalan.xsltc.compiler.util.*;
final class Choose extends Instruction {
private final static String MISSING_WHEN_ERROR =
"At least one When element required in Choose";
private final static String ILLEGAL_ELEMENT_ERROR =
"Only When|Otherwise elements allowed in Choose";
private final static String MULTIPLE_OTHERWISE_ERROR =
"Only one Otherwise element allowed in Choose";
/**
* Display the element contents (a lot of when's and an otherwise)
*/
public void display(int indent) {
indent(indent);
Util.println("Choose");
indent(indent + IndentIncrement);
displayContents(indent + IndentIncrement);
}
/**
* Translate this Choose element. Generate a test-chain for the various
* <xsl:when> elements and default to the <xsl:otherwise> if present.
*/
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
final Vector whenElements = new Vector();
Otherwise otherwise = null;
Enumeration elements = elements();
// These two are for reporting errors only
ErrorMsg error = null;
final int line = getLineNumber();
// Traverse all child nodes - must be either When or Otherwise
while (elements.hasMoreElements()) {
Object element = elements.nextElement();
// Add a When child element
if (element instanceof When) {
whenElements.addElement(element);
}
// Add an Otherwise child element
else if (element instanceof Otherwise) {
if (otherwise == null) {
otherwise = (Otherwise)element;
}
else {
error = new ErrorMsg(MULTIPLE_OTHERWISE_ERROR, line);
getParser().reportError(Constants.ERROR, error);
}
}
// It is an error if we find some other element here
else {
error = new ErrorMsg(ILLEGAL_ELEMENT_ERROR, line);
getParser().reportError(Constants.ERROR, error);
}
}
// Make sure that there is at least one <xsl:when> element
if (whenElements.size() == 0) {
error = new ErrorMsg(MISSING_WHEN_ERROR, getLineNumber());
getParser().reportError(Constants.ERROR, error);
return;
}
InstructionList il = methodGen.getInstructionList();
// next element will hold a handle to the beginning of next
// When/Otherwise if test on current When fails
BranchHandle nextElement = null;
Vector exitHandles = new Vector();
InstructionHandle exit = null;
Enumeration whens = whenElements.elements();
while (whens.hasMoreElements()) {
final When when = (When)whens.nextElement();
final Expression test = when.getTest();
InstructionHandle truec = il.getEnd();
if (nextElement != null)
nextElement.setTarget(il.append(NOP));
test.translateDesynthesized(classGen, methodGen);
if ((test instanceof FunctionCall) &&
!(test instanceof ElementAvailableCall) &&
!(test instanceof ContainsCall))
test._falseList.add(il.append(new IFEQ(null)));
// remember end of condition
truec = il.getEnd();
// The When object should be ignored completely in case it tests
// for the support of a non-available element
if (!when.ignore()) when.translateContents(classGen, methodGen);
// goto exit after executing the body of when
exitHandles.addElement(il.append(new GOTO(null)));
if (whens.hasMoreElements() || otherwise != null) {
nextElement = il.append(new GOTO(null));
test.backPatchFalseList(nextElement);
}
else
test.backPatchFalseList(exit = il.append(NOP));
test.backPatchTrueList(truec.getNext());
}
// Translate any <xsl:otherwise> element
if (otherwise != null) {
nextElement.setTarget(il.append(NOP));
otherwise.translateContents(classGen, methodGen);
exit = il.append(NOP);
}
// now that end is known set targets of exit gotos
Enumeration exitGotos = exitHandles.elements();
while (exitGotos.hasMoreElements()) {
BranchHandle gotoExit = (BranchHandle)exitGotos.nextElement();
gotoExit.setTarget(exit);
}
}
}