/*
* 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: FunctionAvailableCall.java,v 1.19 2004/02/23 10:29:35 aruny Exp $
*/
package org.apache.xalan.xsltc.compiler;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
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;
import org.apache.xalan.xsltc.compiler.util.Util;
/**
* @author G. Todd Miller
* @author Santiago Pericas-Geertsen
*/
final class FunctionAvailableCall extends FunctionCall {
private Expression _arg;
private String _nameOfFunct = null;
private String _namespaceOfFunct = null;
private boolean _isFunctionAvailable = false;
/**
* Constructs a FunctionAvailableCall FunctionCall. Takes the
* function name qname, for example, 'function-available', and
* a list of arguments where the arguments must be instances of
* LiteralExpression.
*/
public FunctionAvailableCall(QName fname, Vector arguments) {
super(fname, arguments);
_arg = (Expression)arguments.elementAt(0);
_type = null;
if (_arg instanceof LiteralExpr) {
LiteralExpr arg = (LiteralExpr) _arg;
_namespaceOfFunct = arg.getNamespace();
_nameOfFunct = arg.getValue();
if (!isInternalNamespace()) {
_isFunctionAvailable = hasMethods();
}
}
}
/**
* Argument of function-available call must be literal, typecheck
* returns the type of function-available to be boolean.
*/
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
if (_type != null) {
return _type;
}
if (_arg instanceof LiteralExpr) {
return _type = Type.Boolean;
}
ErrorMsg err = new ErrorMsg(ErrorMsg.NEED_LITERAL_ERR,
"function-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;
}
/**
* for external java functions only: reports on whether or not
* the specified method is found in the specifed class.
*/
private boolean hasMethods() {
LiteralExpr arg = (LiteralExpr)_arg;
// Get the class name from the namespace uri
String className = getClassNameFromUri(_namespaceOfFunct);
// Get the method name from the argument to function-available
String methodName = null;
int colonIndex = _nameOfFunct.indexOf(":");
if (colonIndex > 0) {
String functionName = _nameOfFunct.substring(colonIndex+1);
int lastDotIndex = functionName.lastIndexOf('.');
if (lastDotIndex > 0) {
methodName = functionName.substring(lastDotIndex+1);
if (className != null && !className.equals(""))
className = className + "." + functionName.substring(0, lastDotIndex);
else
className = functionName.substring(0, lastDotIndex);
}
else
methodName = functionName;
}
else
methodName = _nameOfFunct;
if (className == null || methodName == null) {
return false;
}
// Replace the '-' characters in the method name
if (methodName.indexOf('-') > 0)
methodName = replaceDash(methodName);
try {
final Class clazz = ObjectFactory.findProviderClass(
className, ObjectFactory.findClassLoader(), true);
if (clazz == null) {
return false;
}
final Method[] methods = clazz.getMethods();
for (int i = 0; i < methods.length; i++) {
final int mods = methods[i].getModifiers();
if (Modifier.isPublic(mods) && Modifier.isStatic(mods)
&& methods[i].getName().equals(methodName))
{
return true;
}
}
}
catch (ClassNotFoundException e) {
return false;
}
return false;
}
/**
* Reports on whether the function specified in the argument to
* xslt function 'function-available' was found.
*/
public boolean getResult() {
if (_nameOfFunct == null) {
return false;
}
if (isInternalNamespace()) {
final Parser parser = getParser();
_isFunctionAvailable =
parser.functionSupported(Util.getLocalName(_nameOfFunct));
}
return _isFunctionAvailable;
}
/**
* Return true if the namespace uri is null or it is the XSLTC translet uri.
*/
private boolean isInternalNamespace() {
return (_namespaceOfFunct == null ||
_namespaceOfFunct.equals(EMPTYSTRING) ||
_namespaceOfFunct.equals(TRANSLET_URI));
}
/**
* Calls to 'function-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();
methodGen.getInstructionList().append(new PUSH(cpg, getResult()));
}
}