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	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* 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.
	*/

	package com.sun.org.apache.xalan.internal.xsltc.compiler;

	import com.sun.org.apache.bcel.internal.classfile.Field;
	import com.sun.org.apache.bcel.internal.generic.BranchHandle;
	import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
	import com.sun.org.apache.bcel.internal.generic.IFNONNULL;
	import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
	import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
	import com.sun.org.apache.bcel.internal.generic.Instruction;
	import com.sun.org.apache.bcel.internal.generic.InstructionList;
	import com.sun.org.apache.bcel.internal.generic.PUSH;
	import com.sun.org.apache.bcel.internal.generic.PUTFIELD;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ObjectType;
	import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
	import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;

	/**
	* @author Jacek Ambroziak
	* @author Santiago Pericas-Geertsen
	* @author Morten Jorgensen
	* @author Erwin Bolwidt <ejb@klomp.org>
	* @author John Howard <JohnH@schemasoft.com>
	*/
	final class Param extends VariableBase {

	/**
	* True if this Param is declared in a simple named template.
	* This is used to optimize codegen for parameter passing
	* in named templates.
	*/
	private boolean _isInSimpleNamedTemplate = false;

	/**
	* Display variable as single string
	*/
	public String toString() {
	return "param(" + _name + ")";
	}

	/**
	* Set the instruction for loading the value of this variable onto the
	* JVM stack and returns the old instruction.
	*/
	public Instruction setLoadInstruction(Instruction instruction) {
	Instruction tmp = _loadInstruction;
	_loadInstruction = instruction;
	return tmp;
	}

	/**
	* Set the instruction for storing a value from the stack into this
	* variable and returns the old instruction.
	*/
	public Instruction setStoreInstruction(Instruction instruction) {
	Instruction tmp = _storeInstruction;
	_storeInstruction = instruction;
	return tmp;
	}

	/**
	* Display variable in a full AST dump
	*/
	public void display(int indent) {
	indent(indent);
	System.out.println("param " + _name);
	if (_select != null) {
	indent(indent + IndentIncrement);
	System.out.println("select " + _select.toString());
	}
	displayContents(indent + IndentIncrement);
	}

	/**
	* Parse the contents of the <xsl:param> element. This method must read
	* the 'name' (required) and 'select' (optional) attributes.
	*/
	public void parseContents(Parser parser) {

	// Parse 'name' and 'select' attributes plus parameter contents
	super.parseContents(parser);

	// Add a ref to this param to its enclosing construct
	final SyntaxTreeNode parent = getParent();
	if (parent instanceof Stylesheet) {
	// Mark this as a global parameter
	_isLocal = false;
	// Check if a global variable with this name already exists...
	Param param = parser.getSymbolTable().lookupParam(_name);
	// ...and if it does we need to check import precedence
	if (param != null) {
	final int us = this.getImportPrecedence();
	final int them = param.getImportPrecedence();
	// It is an error if the two have the same import precedence
	if (us == them) {
	final String name = _name.toString();
	reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR,name);
	}
	// Ignore this if previous definition has higher precedence
	else if (them > us) {
	_ignore = true;
	copyReferences(param);
	return;
	}
	else {
	param.copyReferences(this);
	param.disable();
	}
	}
	// Add this variable if we have higher precedence
	((Stylesheet)parent).addParam(this);
	parser.getSymbolTable().addParam(this);
	}
	else if (parent instanceof Template) {
	Template template = (Template) parent;
	_isLocal = true;
	template.addParameter(this);
	if (template.isSimpleNamedTemplate()) {
	_isInSimpleNamedTemplate = true;
	}
	}
	}

	/**
	* Type-checks the parameter. The parameter type is determined by the
	* 'select' expression (if present) or is a result tree if the parameter
	* element has a body and no 'select' expression.
	*/
	public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (_select != null) {
	_type = _select.typeCheck(stable);
	if (_type instanceof ReferenceType == false && !(_type instanceof ObjectType)) {
	_select = new CastExpr(_select, Type.Reference);
	}
	}
	else if (hasContents()) {
	typeCheckContents(stable);
	}
	_type = Type.Reference;

	// This element has no type (the parameter does, but the parameter
	// element itself does not).
	return Type.Void;
	}

	public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	if (_ignore) return;
	_ignore = true;

	/*
	* To fix bug 24518 related to setting parameters of the form
	* {namespaceuri}localName which will get mapped to an instance
	* variable in the class.
	*/
	final String name = BasisLibrary.mapQNameToJavaName(_name.toString());
	final String signature = _type.toSignature();
	final String className = _type.getClassName();

	if (isLocal()) {
	/*
	* If simple named template then generate a conditional init of the
	* param using its default value:
	* if (param == null) param = <default-value>
	*/
	if (_isInSimpleNamedTemplate) {
	il.append(loadInstruction());
	BranchHandle ifBlock = il.append(new IFNONNULL(null));
	translateValue(classGen, methodGen);
	il.append(storeInstruction());
	ifBlock.setTarget(il.append(NOP));
	return;
	}

	il.append(classGen.loadTranslet());
	il.append(new PUSH(cpg, name));
	translateValue(classGen, methodGen);
	il.append(new PUSH(cpg, true));

	// Call addParameter() from this class
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
	ADD_PARAMETER,
	ADD_PARAMETER_SIG)));
	if (className != EMPTYSTRING) {
	il.append(new CHECKCAST(cpg.addClass(className)));
	}

	_type.translateUnBox(classGen, methodGen);

	if (_refs.isEmpty()) { // nobody uses the value
	il.append(_type.POP());
	_local = null;
	}
	else { // normal case
	_local = methodGen.addLocalVariable2(name,
	_type.toJCType(),
	il.getEnd());
	// Cache the result of addParameter() in a local variable
	il.append(_type.STORE(_local.getIndex()));
	}
	}
	else {
	if (classGen.containsField(name) == null) {
	classGen.addField(new Field(ACC_PUBLIC, cpg.addUtf8(name),
	cpg.addUtf8(signature),
	null, cpg.getConstantPool()));
	il.append(classGen.loadTranslet());
	il.append(DUP);
	il.append(new PUSH(cpg, name));
	translateValue(classGen, methodGen);
	il.append(new PUSH(cpg, true));

	// Call addParameter() from this class
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
	ADD_PARAMETER,
	ADD_PARAMETER_SIG)));

	_type.translateUnBox(classGen, methodGen);

	// Cache the result of addParameter() in a field
	if (className != EMPTYSTRING) {
	il.append(new CHECKCAST(cpg.addClass(className)));
	}
	il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(),
	name, signature)));
	}
	}
	}
	}

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