org.apache.commons.collections.list.PredicatedList.java Source code

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Here is the source code for org.apache.commons.collections.list.PredicatedList.java

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/*
 *  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.list;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.collection.PredicatedCollection;
import org.apache.commons.collections.iterators.AbstractListIteratorDecorator;

/**
 * Decorates another <code>List</code> to validate that all additions
 * match a specified predicate.
 * <p>
 * This list exists to provide validation for the decorated list.
 * It is normally created to decorate an empty list.
 * If an object cannot be added to the list, an IllegalArgumentException is thrown.
 * <p>
 * One usage would be to ensure that no null entries are added to the list.
 * <pre>List list = PredicatedList.decorate(new ArrayList(), NotNullPredicate.INSTANCE);</pre>
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 *
 * @since Commons Collections 3.0
 * @version $Revision: 1.6 $ $Date: 2004/06/03 22:02:13 $
 * 
 * @author Stephen Colebourne
 * @author Paul Jack
 */
public class PredicatedList extends PredicatedCollection implements List {

    /** Serialization version */
    private static final long serialVersionUID = -5722039223898659102L;

    /**
     * Factory method to create a predicated (validating) list.
     * <p>
     * If there are any elements already in the list being decorated, they
     * are validated.
     * 
     * @param list  the list to decorate, must not be null
     * @param predicate  the predicate to use for validation, must not be null
     * @throws IllegalArgumentException if list or predicate is null
     * @throws IllegalArgumentException if the list contains invalid elements
     */
    public static List decorate(List list, Predicate predicate) {
        return new PredicatedList(list, predicate);
    }

    //-----------------------------------------------------------------------
    /**
     * Constructor that wraps (not copies).
     * <p>
     * If there are any elements already in the list being decorated, they
     * are validated.
     * 
     * @param list  the list to decorate, must not be null
     * @param predicate  the predicate to use for validation, must not be null
     * @throws IllegalArgumentException if list or predicate is null
     * @throws IllegalArgumentException if the list contains invalid elements
     */
    protected PredicatedList(List list, Predicate predicate) {
        super(list, predicate);
    }

    /**
     * Gets the list being decorated.
     * 
     * @return the decorated list
     */
    protected List getList() {
        return (List) getCollection();
    }

    //-----------------------------------------------------------------------
    public Object get(int index) {
        return getList().get(index);
    }

    public int indexOf(Object object) {
        return getList().indexOf(object);
    }

    public int lastIndexOf(Object object) {
        return getList().lastIndexOf(object);
    }

    public Object remove(int index) {
        return getList().remove(index);
    }

    //-----------------------------------------------------------------------
    public void add(int index, Object object) {
        validate(object);
        getList().add(index, object);
    }

    public boolean addAll(int index, Collection coll) {
        for (Iterator it = coll.iterator(); it.hasNext();) {
            validate(it.next());
        }
        return getList().addAll(index, coll);
    }

    public ListIterator listIterator() {
        return listIterator(0);
    }

    public ListIterator listIterator(int i) {
        return new PredicatedListIterator(getList().listIterator(i));
    }

    public Object set(int index, Object object) {
        validate(object);
        return getList().set(index, object);
    }

    public List subList(int fromIndex, int toIndex) {
        List sub = getList().subList(fromIndex, toIndex);
        return new PredicatedList(sub, predicate);
    }

    /**
     * Inner class Iterator for the PredicatedList
     */
    protected class PredicatedListIterator extends AbstractListIteratorDecorator {

        protected PredicatedListIterator(ListIterator iterator) {
            super(iterator);
        }

        public void add(Object object) {
            validate(object);
            iterator.add(object);
        }

        public void set(Object object) {
            validate(object);
            iterator.set(object);
        }
    }

}