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/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed 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: ElementAvailableCall.java,v 1.2.4.1 2005/09/01 14:13:01 pvedula Exp $
*/
package com.sun.org.apache.xalan.internal.xsltc.compiler;
import java.util.Vector;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.PUSH;
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.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
*/
final class ElementAvailableCall extends FunctionCall {
public ElementAvailableCall(QName fname, Vector arguments) {
super(fname, arguments);
}
/**
* Force the argument to this function to be a literal string.
*/
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
if (argument() instanceof LiteralExpr) {
return _type = Type.Boolean;
}
ErrorMsg err = new ErrorMsg(ErrorMsg.NEED_LITERAL_ERR,
"element-available", this);
throw new TypeCheckError(err);
}
/**
* Returns an object representing the compile-time evaluation
* of an expression. We are only using this for function-available
* and element-available at this time.
*/
public Object evaluateAtCompileTime() {
return getResult() ? Boolean.TRUE : Boolean.FALSE;
}
/**
* Returns the result that this function will return
*/
public boolean getResult() {
try {
final LiteralExpr arg = (LiteralExpr) argument();
final String qname = arg.getValue();
final int index = qname.indexOf(':');
final String localName = (index > 0) ?
qname.substring(index + 1) : qname;
return getParser().elementSupported(arg.getNamespace(),
localName);
}
catch (ClassCastException e) {
return false;
}
}
/**
* Calls to 'element-available' are resolved at compile time since
* the namespaces declared in the stylsheet are not available at run
* time. Consequently, arguments to this function must be literals.
*/
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final boolean result = getResult();
methodGen.getInstructionList().append(new PUSH(cpg, result));
}
}
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