- /*
- * Copyright 2003-2004 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.collection;
-
- import java.util.Collection;
- import java.util.Iterator;
-
- import org.apache.commons.collections.Predicate;
-
- /**
- * Decorates another <code>Collection</code> to validate that additions
- * match a specified predicate.
- * <p>
- * This collection exists to provide validation for the decorated collection.
- * It is normally created to decorate an empty collection.
- * If an object cannot be added to the collection, an IllegalArgumentException is thrown.
- * <p>
- * One usage would be to ensure that no null entries are added to the collection.
- * <pre>Collection coll = PredicatedCollection.decorate(new ArrayList(), NotNullPredicate.INSTANCE);</pre>
- * <p>
- * This class is Serializable from Commons Collections 3.1.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.7 $ $Date: 2004/06/03 22:02:13 $
- *
- * @author Stephen Colebourne
- * @author Paul Jack
- */
- public class PredicatedCollection extends AbstractSerializableCollectionDecorator {
-
- /** Serialization version */
- private static final long serialVersionUID = -5259182142076705162L;
-
- /** The predicate to use */
- protected final Predicate predicate;
-
- /**
- * Factory method to create a predicated (validating) collection.
- * <p>
- * If there are any elements already in the collection being decorated, they
- * are validated.
- *
- * @param coll the collection to decorate, must not be null
- * @param predicate the predicate to use for validation, must not be null
- * @return a new predicated collection
- * @throws IllegalArgumentException if collection or predicate is null
- * @throws IllegalArgumentException if the collection contains invalid elements
- */
- public static Collection decorate(Collection coll, Predicate predicate) {
- return new PredicatedCollection(coll, predicate);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Constructor that wraps (not copies).
- * <p>
- * If there are any elements already in the collection being decorated, they
- * are validated.
- *
- * @param coll the collection to decorate, must not be null
- * @param predicate the predicate to use for validation, must not be null
- * @throws IllegalArgumentException if collection or predicate is null
- * @throws IllegalArgumentException if the collection contains invalid elements
- */
- protected PredicatedCollection(Collection coll, Predicate predicate) {
- super(coll);
- if (predicate == null) {
- throw new IllegalArgumentException("Predicate must not be null");
- }
- this.predicate = predicate;
- for (Iterator it = coll.iterator(); it.hasNext(); ) {
- validate(it.next());
- }
- }
-
- /**
- * Validates the object being added to ensure it matches the predicate.
- * <p>
- * The predicate itself should not throw an exception, but return false to
- * indicate that the object cannot be added.
- *
- * @param object the object being added
- * @throws IllegalArgumentException if the add is invalid
- */
- protected void validate(Object object) {
- if (predicate.evaluate(object) == false) {
- throw new IllegalArgumentException("Cannot add Object '" + object + "' - Predicate rejected it");
- }
- }
-
- //-----------------------------------------------------------------------
- /**
- * Override to validate the object being added to ensure it matches
- * the predicate.
- *
- * @param object the object being added
- * @return the result of adding to the underlying collection
- * @throws IllegalArgumentException if the add is invalid
- */
- public boolean add(Object object) {
- validate(object);
- return getCollection().add(object);
- }
-
- /**
- * Override to validate the objects being added to ensure they match
- * the predicate. If any one fails, no update is made to the underlying
- * collection.
- *
- * @param coll the collection being added
- * @return the result of adding to the underlying collection
- * @throws IllegalArgumentException if the add is invalid
- */
- public boolean addAll(Collection coll) {
- for (Iterator it = coll.iterator(); it.hasNext(); ) {
- validate(it.next());
- }
- return getCollection().addAll(coll);
- }
-
- }