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/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003-2004 The Apache Software Foundation. All rights
* reserved.
*
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* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* Map implementation that maintains the order of the entries.
* In this implementation order is maintained by original insertion.
*
* This implementation improves on the JDK1.4 LinkedHashMap by adding the
* {@link org.apache.commons.collections.MapIterator MapIterator}
* functionality, additional convenience methods and allowing
* bidirectional iteration. It also implements OrderedMap.
* In addition, non-interface methods are provided to access the map by index.
*
* The orderedMapIterator() method provides direct access to a
* bidirectional iterator. The iterators from the other views can also be cast
* to OrderedIterator if required.
*
* All the available iterators can be reset back to the start by casting to
* ResettableIterator and calling reset().
*
* The implementation is also designed to be subclassed, with lots of useful
* methods exposed.
*
* @since Commons Collections 3.0
* @version $Revision: 1.8 $ $Date: 2004/01/14 21:43:11 $
*
* @author Stephen Colebourne
*/
public class LinkedMap
extends AbstractLinkedMap implements Serializable, Cloneable {
/** Serialisation version */
private static final long serialVersionUID = 9077234323521161066L;
/**
* Constructs a new empty map with default size and load factor.
*/
public LinkedMap() {
super(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_THRESHOLD);
}
/**
* Constructs a new, empty map with the specified initial capacity.
*
* @param initialCapacity the initial capacity
* @throws IllegalArgumentException if the initial capacity is less than one
*/
public LinkedMap(int initialCapacity) {
super(initialCapacity);
}
/**
* Constructs a new, empty map with the specified initial capacity and
* load factor.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
* @throws IllegalArgumentException if the initial capacity is less than one
* @throws IllegalArgumentException if the load factor is less than zero
*/
public LinkedMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Constructor copying elements from another map.
*
* @param map the map to copy
* @throws NullPointerException if the map is null
*/
public LinkedMap(Map map) {
super(map);
}
//-----------------------------------------------------------------------
/**
* Clones the map without cloning the keys or values.
*
* @return a shallow clone
*/
public Object clone() {
return super.clone();
}
/**
* Write the map out using a custom routine.
*/
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
doWriteObject(out);
}
/**
* Read the map in using a custom routine.
*/
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
doReadObject(in);
}
//-----------------------------------------------------------------------
/**
* Gets the key at the specified index.
*
* @param index the index to retrieve
* @return the key at the specified index
* @throws IndexOutOfBoundsException if the index is invalid
*/
public Object get(int index) {
return getEntry(index).getKey();
}
/**
* Gets the value at the specified index.
*
* @param index the index to retrieve
* @return the key at the specified index
* @throws IndexOutOfBoundsException if the index is invalid
*/
public Object getValue(int index) {
return getEntry(index).getValue();
}
/**
* Gets the index of the specified key.
*
* @param key the key to find the index of
* @return the index, or -1 if not found
*/
public int indexOf(Object key) {
key = convertKey(key);
int i = 0;
for (LinkEntry entry = header.after; entry != header; entry = entry.after, i++) {
if (isEqualKey(key, entry.key)) {
return i;
}
}
return -1;
}
/**
* Removes the element at the specified index.
*
* @param index the index of the object to remove
* @return the previous value corresponding the key,
* or null if none existed
* @throws IndexOutOfBoundsException if the index is invalid
*/
public Object remove(int index) {
return remove(get(index));
}
/**
* Gets an unmodifiable List view of the keys.
*
* The returned list is unmodifiable because changes to the values of
* the list (using {@link java.util.ListIterator#set(Object)}) will
* effectively remove the value from the list and reinsert that value at
* the end of the list, which is an unexpected side effect of changing the
* value of a list. This occurs because changing the key, changes when the
* mapping is added to the map and thus where it appears in the list.
*
* An alternative to this method is to use {@link #keySet()}.
*
* @see #keySet()
* @return The ordered list of keys.
*/
public List asList() {
return new LinkedMapList(this);
}
/**
* List view of map.
*/
static class LinkedMapList extends AbstractList {
final LinkedMap parent;
LinkedMapList(LinkedMap parent) {
this.parent = parent;
}
public int size() {
return parent.size();
}
public Object get(int index) {
return parent.get(index);
}
public boolean contains(Object obj) {
return parent.containsKey(obj);
}
public int indexOf(Object obj) {
return parent.indexOf(obj);
}
public int lastIndexOf(Object obj) {
return parent.indexOf(obj);
}
public boolean containsAll(Collection coll) {
return parent.keySet().containsAll(coll);
}
public Object remove(int index) {
throw new UnsupportedOperationException();
}
public boolean remove(Object obj) {
throw new UnsupportedOperationException();
}
public boolean removeAll(Collection coll) {
throw new UnsupportedOperationException();
}
public boolean retainAll(Collection coll) {
throw new UnsupportedOperationException();
}
public void clear() {
throw new UnsupportedOperationException();
}
public Object[] toArray() {
return parent.keySet().toArray();
}
public Object[] toArray(Object[] array) {
return parent.keySet().toArray(array);
}
public Iterator iterator() {
return UnmodifiableIterator.decorate(parent.keySet().iterator());
}
public ListIterator listIterator() {
return UnmodifiableListIterator.decorate(super.listIterator());
}
public ListIterator listIterator(int fromIndex) {
return UnmodifiableListIterator.decorate(super.listIterator(fromIndex));
}
public List subList(int fromIndexInclusive, int toIndexExclusive) {
return UnmodifiableList.decorate(super.subList(fromIndexInclusive, toIndexExclusive));
}
}
}