- /*
- * 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.
- */
- package org.apache.commons.collections.functors;
-
- import java.io.Serializable;
- import java.lang.reflect.Constructor;
- import java.lang.reflect.InvocationTargetException;
-
- import org.apache.commons.collections.Factory;
- import org.apache.commons.collections.FunctorException;
-
- /**
- * Factory implementation that creates a new object instance by reflection.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.6 $ $Date: 2004/05/16 11:47:38 $
- *
- * @author Stephen Colebourne
- */
- public class InstantiateFactory implements Factory, Serializable {
-
- /** The serial version */
- static final long serialVersionUID = -7732226881069447957L;
-
- /** The class to create */
- private final Class iClassToInstantiate;
- /** The constructor parameter types */
- private final Class[] iParamTypes;
- /** The constructor arguments */
- private final Object[] iArgs;
- /** The constructor */
- private transient Constructor iConstructor = null;
-
- /**
- * Factory method that performs validation.
- *
- * @param classToInstantiate the class to instantiate, not null
- * @param paramTypes the constructor parameter types
- * @param args the constructor arguments
- * @return a new instantiate factory
- */
- public static Factory getInstance(Class classToInstantiate, Class[] paramTypes, Object[] args) {
- if (classToInstantiate == null) {
- throw new IllegalArgumentException("Class to instantiate must not be null");
- }
- if (((paramTypes == null) && (args != null))
- || ((paramTypes != null) && (args == null))
- || ((paramTypes != null) && (args != null) && (paramTypes.length != args.length))) {
- throw new IllegalArgumentException("Parameter types must match the arguments");
- }
-
- if (paramTypes == null || paramTypes.length == 0) {
- return new InstantiateFactory(classToInstantiate);
- } else {
- paramTypes = (Class[]) paramTypes.clone();
- args = (Object[]) args.clone();
- return new InstantiateFactory(classToInstantiate, paramTypes, args);
- }
- }
-
- /**
- * Constructor that performs no validation.
- * Use <code>getInstance</code> if you want that.
- *
- * @param classToInstantiate the class to instantiate
- */
- public InstantiateFactory(Class classToInstantiate) {
- super();
- iClassToInstantiate = classToInstantiate;
- iParamTypes = null;
- iArgs = null;
- findConstructor();
- }
-
- /**
- * Constructor that performs no validation.
- * Use <code>getInstance</code> if you want that.
- *
- * @param classToInstantiate the class to instantiate
- * @param paramTypes the constructor parameter types, not cloned
- * @param args the constructor arguments, not cloned
- */
- public InstantiateFactory(Class classToInstantiate, Class[] paramTypes, Object[] args) {
- super();
- iClassToInstantiate = classToInstantiate;
- iParamTypes = paramTypes;
- iArgs = args;
- findConstructor();
- }
-
- /**
- * Find the Constructor for the class specified.
- */
- private void findConstructor() {
- try {
- iConstructor = iClassToInstantiate.getConstructor(iParamTypes);
-
- } catch (NoSuchMethodException ex) {
- throw new IllegalArgumentException("InstantiateFactory: The constructor must exist and be public ");
- }
- }
-
- /**
- * Creates an object using the stored constructor.
- *
- * @return the new object
- */
- public Object create() {
- // needed for post-serialization
- if (iConstructor == null) {
- findConstructor();
- }
-
- try {
- return iConstructor.newInstance(iArgs);
-
- } catch (InstantiationException ex) {
- throw new FunctorException("InstantiateFactory: InstantiationException", ex);
- } catch (IllegalAccessException ex) {
- throw new FunctorException("InstantiateFactory: Constructor must be public", ex);
- } catch (InvocationTargetException ex) {
- throw new FunctorException("InstantiateFactory: Constructor threw an exception", ex);
- }
- }
-
- }