/*
 * 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 com.sun.org.apache.xerces.internal.xs;

/**
 * Objects implementing the <code>XSNamedMap</code> interface are used to 
 * represent immutable collections of XML Schema components that can be 
 * accessed by name. Note that <code>XSNamedMap</code> does not inherit from 
 * <code>XSObjectList</code>. The <code>XSObject</code>s in 
 * <code>XSNamedMap</code>s are not maintained in any particular order. 
 */
public interface XSNamedMap {
    /**
     * The number of <code>XSObjects</code> in the <code>XSObjectList</code>. 
     * The range of valid child object indices is 0 to <code>length-1</code> 
     * inclusive. 
     */
    public int getLength();

    /**
     *  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>XSObject</code> at the <code>index</code>th 
     *   position in the <code>XSObjectList</code>, or <code>null</code> if 
     *   the index specified is not valid. 
     */
    public XSObject item(int index);

    /**
     * Retrieves an <code>XSObject</code> specified by local name and 
     * namespace URI.
     * <br>Per XML Namespaces, applications must use the value <code>null</code> as the 
     * <code>namespace</code> parameter for methods if they wish to specify 
     * no namespace.
     * @param namespace The namespace URI of the <code>XSObject</code> to 
     *   retrieve, or <code>null</code> if the <code>XSObject</code> has no 
     *   namespace. 
     * @param localName The local name of the <code>XSObject</code> to 
     *   retrieve.
     * @return A <code>XSObject</code> (of any type) with the specified local 
     *   name and namespace URI, or <code>null</code> if they do not 
     *   identify any object in this map.
     */
    public XSObject itemByName(String namespace, 
                               String localName);

}
