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jtstand-common is a library derived from jcommon, used by jtstand-chart, which is derived from jfreechart
/*
* Copyright (c) 2009 Albert Kurucz.
*
* This file, HashNMap.java is part of JTStand.
*
* JTStand is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JTStand is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with GTStand. If not, see hasNext is called.
*/
private static final class EmptyIterator implements Iterator {
/**
* DefaultConstructor.
*/
private EmptyIterator() {
super();
}
/**
* Returns true if the iteration has more elements. (In other
* words, returns true if next would return an element
* rather than throwing an exception.)
*
* @return true if the iterator has more elements.
*/
public boolean hasNext() {
return false;
}
/**
* Returns the next element in the iteration.
*
* @return the next element in the iteration.
* @throws NoSuchElementException iteration has no more elements.
*/
public Object next() {
throw new NoSuchElementException("This iterator is empty.");
}
/**
* Removes from the underlying collection the last element returned by the
* iterator (optional operation). This method can be called only once per
* call to next. The behavior of an iterator is unspecified if
* the underlying collection is modified while the iteration is in
* progress in any way other than by calling this method.
*
* @throws UnsupportedOperationException if the remove
* operation is not supported by this Iterator.
* @throws IllegalStateException if the next method has not
* yet been called, or the remove method has already
* been called after the last call to the next
* method.
*/
public void remove() {
throw new UnsupportedOperationException("This iterator is empty, no remove supported.");
}
}
/**
* A singleton instance of the empty iterator. This object can be safely
* shared.
*/
private static final Iterator EMPTY_ITERATOR = new EmptyIterator();
/**
* The underlying storage.
*/
private HashMap table;
/**
* An empty array.
*/
private static final Object[] EMPTY_ARRAY = new Object[0];
/**
* Default constructor.
*/
public HashNMap() {
this.table = new HashMap();
}
/**
* Returns a new empty list.
*
* @return A new empty list.
*/
protected List createList() {
return new ArrayList();
}
/**
* Inserts a new key/value pair into the map. If such a pair already
* exists, it gets replaced with the given values.
*
* @param key the key.
* @param val the value.
* @return A boolean.
*/
public boolean put(final Object key, final Object val) {
final List v = (List) this.table.get(key);
if (v == null) {
final List newList = createList();
newList.add(val);
this.table.put(key, newList);
return true;
}
else {
v.clear();
return v.add(val);
}
}
/**
* Adds a new key/value pair into this map. If the key is not yet in the
* map, it gets added to the map and the call is equal to
* put(Object,Object).
*
* @param key the key.
* @param val the value.
* @return true, if the value has been added, false otherwise
*/
public boolean add(final Object key, final Object val) {
final List v = (List) this.table.get(key);
if (v == null) {
put(key, val);
return true;
}
else {
return v.add(val);
}
}
/**
* Retrieves the first value registered for an key or null if there was no
* such key in the list.
*
* @param key the key.
* @return the value.
*/
public Object getFirst(final Object key) {
return get(key, 0);
}
/**
* Retrieves the n-th value registered for an key or null if there was no
* such key in the list. An index out of bounds exception is thrown if
* there are less than n elements registered to this key.
*
* @param key the key.
* @param n the index.
* @return the object.
*/
public Object get(final Object key, final int n) {
final List v = (List) this.table.get(key);
if (v == null) {
return null;
}
return v.get(n);
}
/**
* Returns an iterator over all elements registered to the given key.
*
* @param key the key.
* @return an iterator.
*/
public Iterator getAll(final Object key) {
final List v = (List) this.table.get(key);
if (v == null) {
return EMPTY_ITERATOR;
}
return v.iterator();
}
/**
* Returns all registered keys as an enumeration.
*
* @return an enumeration of the keys.
*/
public Iterator keys() {
return this.table.keySet().iterator();
}
/**
* Returns all registered keys as set.
*
* @return a set of keys.
*/
public Set keySet() {
return this.table.keySet();
}
/**
* Removes the key/value pair from the map. If the removed entry was the
* last entry for this key, the key gets also removed.
*
* @param key the key.
* @param value the value.
* @return true, if removing the element was successfull, false otherwise.
*/
public boolean remove(final Object key, final Object value) {
final List v = (List) this.table.get(key);
if (v == null) {
return false;
}
if (!v.remove(value)) {
return false;
}
if (v.size() == 0) {
this.table.remove(key);
}
return true;
}
/**
* Removes all elements for the given key.
*
* @param key the key.
*/
public void removeAll(final Object key) {
this.table.remove(key);
}
/**
* Clears all keys and values of this map.
*/
public void clear() {
this.table.clear();
}
/**
* Tests whether this map contains the given key.
*
* @param key the key.
* @return true if the key is contained in the map
*/
public boolean containsKey(final Object key) {
return this.table.containsKey(key);
}
/**
* Tests whether this map contains the given value.
*
* @param value the value.
* @return true if the value is registered in the map for an key.
*/
public boolean containsValue(final Object value) {
final Iterator e = this.table.values().iterator();
boolean found = false;
while (e.hasNext() && !found) {
final List v = (List) e.next();
found = v.contains(value);
}
return found;
}
/**
* Tests whether this map contains the given value.
*
* @param value the value.
* @param key the key under which to find the value
* @return true if the value is registered in the map for an key.
*/
public boolean containsValue(final Object key, final Object value) {
final List v = (List) this.table.get(key);
if (v == null) {
return false;
}
return v.contains(value);
}
/**
* Tests whether this map contains the given key or value.
*
* @param value the value.
* @return true if the key or value is contained in the map
*/
public boolean contains(final Object value) {
if (containsKey(value)) {
return true;
}
return containsValue(value);
}
/**
* Creates a deep copy of this HashNMap.
*
* @return a clone.
* @throws CloneNotSupportedException this should never happen.
*/
public Object clone() throws CloneNotSupportedException {
final HashNMap map = (HashNMap) super.clone();
map.table = new HashMap();
final Iterator iterator = keys();
while (iterator.hasNext()) {
final Object key = iterator.next();
final List list = (List) map.table.get(key);
if (list != null) {
map.table.put(key, ObjectUtilities.clone(list));
}
}
return map;
}
/**
* Returns the contents for the given key as object array. If there were
* no objects registered with that key, an empty object array is returned.
*
* @param key the key.
* @param data the object array to receive the contents.
* @return the contents.
*/
public Object[] toArray(final Object key, final Object[] data) {
if (key == null) {
throw new NullPointerException("Key must not be null.");
}
final List list = (List) this.table.get(key);
if (list != null) {
return list.toArray(data);
}
if (data.length > 0) {
data[0] = null;
}
return data;
}
/**
* Returns the contents for the given key as object array. If there were
* no objects registered with that key, an empty object array is returned.
*
* @param key the key.
* @return the contents.
*/
public Object[] toArray(final Object key) {
if (key == null) {
throw new NullPointerException("Key must not be null.");
}
final List list = (List) this.table.get(key);
if (list != null) {
return list.toArray();
}
return EMPTY_ARRAY;
}
/**
* Returns the number of elements registered with the given key.
*
* @param key the key.
* @return the number of element for this key, or 0 if there are no elements
* registered.
*/
public int getValueCount(final Object key) {
if (key == null) {
throw new NullPointerException("Key must not be null.");
}
final List list = (List) this.table.get(key);
if (list != null) {
return list.size();
}
return 0;
}
}
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