- /*
- * 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 1.10 2004/02/16 22:24:28 minchau 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));
- }
- }