jaxp/src/java.xml/share/classes/com/sun/org/apache/xerces/internal/xs/datatypes/ObjectList.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
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 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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package com.sun.org.apache.xerces.internal.xs.datatypes;

import java.util.List;

/**
 * <p>The <code>ObjectList</code> is an immutable ordered collection of
 * <code>Object</code>.</p>
 *
 * @author Ankit Pasricha, IBM
 *
 */
public interface ObjectList extends List {

    /**
     * The number of <code>Object</code>s in the list. The range of
     * valid child object indices is 0 to <code>length-1</code> inclusive.
     */
    public int getLength();

    /**
     * Checks if the <code>Object</code> <code>item</code> is a
     * member of this list.
     * @param item  <code>Object</code> whose presence in this list
     *   is to be tested.
     * @return  True if this list contains the <code>Object</code>
     *   <code>item</code>.
     */
    public boolean contains(Object item);

    /**
     * Returns the <code>index</code>th item in the collection or
     * <code>null</code> if <code>index</code> is greater than or equal to
     * the number of objects in the list. The index starts at 0.
     * @param index  index into the collection.
     * @return  The <code>Object</code> at the <code>index</code>th
     *   position in the <code>ObjectList</code>, or <code>null</code> if
     *   the index specified is not valid - greater than or equal to the
     *   number of items in the list or less than zero.
     */
    public Object item(int index);

}