| /* |
| * 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. |
| */ |
| /* |
| * $Id$ |
| */ |
| |
| package org.apache.xalan.xsltc.compiler; |
| |
| import java.util.Vector; |
| |
| import org.apache.bcel.generic.ConstantPoolGen; |
| import org.apache.bcel.generic.PUSH; |
| import org.apache.xalan.xsltc.compiler.util.ClassGenerator; |
| import org.apache.xalan.xsltc.compiler.util.ErrorMsg; |
| import org.apache.xalan.xsltc.compiler.util.MethodGenerator; |
| import org.apache.xalan.xsltc.compiler.util.Type; |
| import org.apache.xalan.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)); |
| } |
| } |