- /*
- * Copyright 1999-2004 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.
- */
- package org.apache.commons.jxpath;
-
- import java.lang.reflect.Constructor;
- import java.lang.reflect.Method;
- import java.util.Collections;
- import java.util.Set;
-
- import org.apache.commons.jxpath.functions.ConstructorFunction;
- import org.apache.commons.jxpath.functions.MethodFunction;
- import org.apache.commons.jxpath.util.MethodLookupUtils;
-
- /**
- * Extension functions provided by a Java class.
- *
- * Let's say, we declared a ClassFunction like this:
- * <blockquote><pre>
- * new ClassFunctions(Integer.class, "int")
- * </pre></blockquote>
- *
- * We can now use XPaths like:
- * <dl>
- * <dt><code>"int:new(3)"</code></dt>
- * <dd>Equivalent to <code>new Integer(3)</code></dd>
- * <dt><code>"int:getInteger('foo')"</code></dt>
- * <dd>Equivalent to <code>Integer.getInteger("foo")</code></dd>
- * <dt><code>"int:floatValue(int:new(4))"</code></dt>
- * <dd>Equivalent to <code>new Integer(4).floatValue()</code></dd>
- * </dl>
- *
- * <p>
- * If the first argument of a method is ExpressionContext, the
- * expression context in which the function is evaluated is passed to
- * the method.
- *
- * @author Dmitri Plotnikov
- * @version $Revision: 1.9 $ $Date: 2004/02/29 14:17:42 $
- */
- public class ClassFunctions implements Functions {
- private Class functionClass;
- private String namespace;
- private static final Object[] EMPTY_ARRAY = new Object[0];
-
- public ClassFunctions(Class functionClass, String namespace) {
- this.functionClass = functionClass;
- this.namespace = namespace;
- }
-
- /**
- * Returns a set of one namespace - the one specified in the constructor.
- *
- * @returns a singleton
- */
- public Set getUsedNamespaces() {
- return Collections.singleton(namespace);
- }
-
- /**
- * Returns a Function, if any, for the specified namespace,
- * name and parameter types.
- *
- * @param namespace if it is not the namespace specified in the constructor,
- * the method returns null
- * @param name is a function name or "new" for a constructor.
- *
- * @return a MethodFunction, a ConstructorFunction or null if there is no
- * such function.
- */
- public Function getFunction(
- String namespace,
- String name,
- Object[] parameters)
- {
- if (!namespace.equals(this.namespace)) {
- return null;
- }
-
- if (parameters == null) {
- parameters = EMPTY_ARRAY;
- }
-
- if (name.equals("new")) {
- Constructor constructor =
- MethodLookupUtils.lookupConstructor(functionClass, parameters);
- if (constructor != null) {
- return new ConstructorFunction(constructor);
- }
- }
- else {
- Method method = MethodLookupUtils.
- lookupStaticMethod(functionClass, name, parameters);
- if (method != null) {
- return new MethodFunction(method);
- }
-
- method = MethodLookupUtils.
- lookupMethod(functionClass, name, parameters);
- if (method != null) {
- return new MethodFunction(method);
- }
- }
-
- return null;
- }
- }