/*
 * 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
 * 
 * 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.xerces.impl.xs.util;

import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;

import javax.xml.XMLConstants;
import javax.xml.namespace.QName;

import org.apache.xerces.util.SymbolHash;
import org.apache.xerces.xs.XSNamedMap;
import org.apache.xerces.xs.XSObject;

Contains the map between qnames and XSObject's.
Author:
Sandy Gao, IBM, Michael Glavassevich, IBM
@xerces.internal
Version:
$Id: XSNamedMapImpl.java 965315 2010-07-18 23:06:35Z mrglavas $/**
 * Contains the map between qnames and XSObject's.
 *
 * @xerces.internal 
 *
 * @author Sandy Gao, IBM
 * @author Michael Glavassevich, IBM
 *
 * @version $Id: XSNamedMapImpl.java 965315 2010-07-18 23:06:35Z mrglavas $
 */
public class XSNamedMapImpl extends AbstractMap implements XSNamedMap {

    
An immutable empty map.
/**
     * An immutable empty map.
     */
    public static final XSNamedMapImpl EMPTY_MAP = new XSNamedMapImpl(new XSObject[0], 0);
    
    // components of these namespaces are stored in this map
    final String[] fNamespaces;
    // number of namespaces
    final int fNSNum;
    // each entry contains components in one namespace
    final SymbolHash[] fMaps;
    // store all components from all namespace.
    // used when this map is accessed as a list.
    XSObject[] fArray = null;
    // store the number of components.
    // used when this map is accessed as a list.
    int fLength = -1;
    // Set of Map.Entry<QName,XSObject> for the java.util.Map methods
    private Set fEntrySet = null;
    
    
Construct an XSNamedMap implementation for one namespace
Params:
namespace – the namespace to which the components belong
map –       the map from local names to components/**
     * Construct an XSNamedMap implementation for one namespace
     * 
     * @param namespace the namespace to which the components belong
     * @param map       the map from local names to components
     */
    public XSNamedMapImpl(String namespace, SymbolHash map) {
        fNamespaces = new String[] {namespace};
        fMaps = new SymbolHash[] {map};
        fNSNum = 1;
    }

    
Construct an XSNamedMap implementation for a list of namespaces
Params:
namespaces – the namespaces to which the components belong
maps –       the maps from local names to components
num –        the number of namespaces/**
     * Construct an XSNamedMap implementation for a list of namespaces
     * 
     * @param namespaces the namespaces to which the components belong
     * @param maps       the maps from local names to components
     * @param num        the number of namespaces
     */
    public XSNamedMapImpl(String[] namespaces, SymbolHash[] maps, int num) {
        fNamespaces = namespaces;
        fMaps = maps;
        fNSNum = num;
    }

    
Construct an XSNamedMap implementation one namespace from an array
Params:
array –     containing all components
length –    number of components/**
     * Construct an XSNamedMap implementation one namespace from an array
     * 
     * @param array     containing all components
     * @param length    number of components
     */
    public XSNamedMapImpl(XSObject[] array, int length) {
        if (length == 0) {
            fNamespaces = null;
            fMaps = null;
            fNSNum = 0;
            fArray = array;
            fLength = 0;
            return;
        }
        // because all components are from the same target namesapce,
        // get the namespace from the first one.
        fNamespaces = new String[]{array[0].getNamespace()};
        fMaps = null;
        fNSNum = 1;
        // copy elements to the Vector
        fArray = array;
        fLength = length;
    }

    
The number of XSObjects in the XSObjectList. 
The range of valid child object indices is 0 to length-1 
inclusive. 
/**
     * 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 synchronized int getLength() {
        if (fLength == -1) {
            fLength = 0;
            for (int i = 0; i < fNSNum; i++) {
                fLength += fMaps[i].getLength();
            }
        }
        return fLength;
    }

    
Retrieves an XSObject specified by local name and 
namespace URI.

Per XML Namespaces, applications must use the value null as the 
namespace parameter for methods if they wish to specify 
no namespace.
Params:
namespace – The namespace URI of the XSObject to 
  retrieve, or null if the XSObject has no 
  namespace.
localName – The local name of the XSObject to 
  retrieve.
Returns:
A XSObject (of any type) with the specified local 
  name and namespace URI, or null if they do not 
  identify any object in this map./**
     * 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) {
        for (int i = 0; i < fNSNum; i++) {
            if (isEqual(namespace, fNamespaces[i])) {
                // when this map is created from SymbolHash's
                // get the component from SymbolHash
                if (fMaps != null) {
                    return (XSObject)fMaps[i].get(localName);
                }
                // Otherwise (it's created from an array)
                // go through the array to find a matching name
                XSObject ret;
                for (int j = 0; j < fLength; j++) {
                    ret = fArray[j];
                    if (ret.getName().equals(localName)) {
                        return ret;
                    }
                }
                return null;
            }
        }
        return null;
    }

    
Returns the indexth item in the collection or 
null if index is greater than or equal to 
the number of objects in the list. The index starts at 0. 
Params:
index –  index into the collection.
Returns:
 The XSObject at the indexth 
  position in the XSObjectList, or null if 
  the index specified is not valid./**
     * 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 synchronized XSObject item(int index) {
        if (fArray == null) {
            // calculate the total number of elements
            getLength();
            fArray = new XSObject[fLength];
            int pos = 0;
            // get components from all SymbolHashes
            for (int i = 0; i < fNSNum; i++) {
                pos += fMaps[i].getValues(fArray, pos);
            }
        }
        if (index < 0 || index >= fLength) {
            return null;
        }
        return fArray[index];
    }
    
    static boolean isEqual(String one, String two) {
        return (one != null) ? one.equals(two) : (two == null);
    }
    
    /*
     * java.util.Map methods
     */
    
    public boolean containsKey(Object key) {
        return (get(key) != null);
    }
    
    public Object get(Object key) {
        if (key instanceof QName) {
            final QName name = (QName) key;
            String namespaceURI = name.getNamespaceURI();
            if (XMLConstants.NULL_NS_URI.equals(namespaceURI)) {
                namespaceURI = null;
            }
            String localPart = name.getLocalPart();
            return itemByName(namespaceURI, localPart);
        }
        return null;
    }
    
    public int size() {
        return getLength();
    }

    public synchronized Set entrySet() {
        // Defer creation of the entry set until it is actually needed.
        if (fEntrySet == null) {
            final int length = getLength();
            final XSNamedMapEntry[] entries = new XSNamedMapEntry[length];
            for (int i = 0; i < length; ++i) {
                XSObject xso = item(i);
                entries[i] = new XSNamedMapEntry(new QName(xso.getNamespace(), xso.getName()), xso);
            }
            // Create a view of this immutable map.
            fEntrySet = new AbstractSet() {
                public Iterator iterator() {
                    return new Iterator() {
                        private int index = 0;
                        public boolean hasNext() {
                            return (index < length);
                        }
                        public Object next() {
                            if (index < length) {
                                return entries[index++];
                            }
                            throw new NoSuchElementException();
                        }
                        public void remove() {
                            throw new UnsupportedOperationException();
                        }
                    };
                }
                public int size() {
                    return length;
                }
            };
        }
        return fEntrySet;
    }
    
    
An entry in the XSNamedMap. /** An entry in the XSNamedMap. **/
    private static final class XSNamedMapEntry implements Map.Entry {
        private final QName key;
        private final XSObject value;
        public XSNamedMapEntry(QName key, XSObject value) {
            this.key = key;
            this.value = value;
        }
        public Object getKey() {
            return key;
        }
        public Object getValue() {
            return value;
        }
        public Object setValue(Object value) {
            throw new UnsupportedOperationException();
        }
        public boolean equals(Object o) {
            if (o instanceof Map.Entry) {
                Map.Entry e = (Map.Entry) o;
                Object otherKey = e.getKey();
                Object otherValue = e.getValue();
                return (key == null ? otherKey == null : key.equals(otherKey)) &&
                    (value == null ? otherValue == null : value.equals(otherValue));
            }
            return false;
        }
        public int hashCode() {
            return (key == null ? 0 : key.hashCode()) 
                ^ (value == null ? 0 : value.hashCode());
        }
        public String toString() {
            StringBuffer buffer = new StringBuffer();
            buffer.append(String.valueOf(key));
            buffer.append('=');
            buffer.append(String.valueOf(value));
            return buffer.toString();
        }
    }
    
} // class XSNamedMapImpl