/*
* LingPipe v. 3.9
* Copyright (C) 2003-2010 Alias-i
*
* This program is licensed under the Alias-i Royalty Free License
* Version 1 WITHOUT ANY WARRANTY, without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Alias-i
* Royalty Free License Version 1 for more details.
*
* You should have received a copy of the Alias-i Royalty Free License
* Version 1 along with this program; if not, visit
* http://alias-i.com/lingpipe/licenses/lingpipe-license-1.txt or contact
* Alias-i, Inc. at 181 North 11th Street, Suite 401, Brooklyn, NY 11211,
* +1 (718) 290-9170.
*/
//package com.aliasi.util;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
/**
* An ObjectToSet provides a {@link java.util.Map} from
* arbitrary objects to objects of class {@link java.util.Set}.
* In addition to methods inherited from {@link java.util.Map},
* there are methods to add members to a set value and get
* set values directly.
*
* @author Bob Carpenter
* @version 3.8
* @since LingPipe1.0
* @param the type of keys for this mapping
* @param the type of members stored in the value sets for this
* map
*/
public class ObjectToSet extends HashMap> {
static final long serialVersionUID = -5758024598554958671L;
/**
* Construct a new object to set mapping.
*/
public ObjectToSet() {
super();
}
/**
* Add a member to the value of the set mapped to by
* the specified key.
*
* @param key Key whose set value will have the object.
* @param member Object to add to the value of the key.
*/
public void addMember(K key, M member) {
if (containsKey(key)) {
get(key).add(member);
} else {
HashSet val = new HashSet();
val.add(member);
put(key,val);
}
}
/**
* Removes the specified value from the set of values assigned to
* the specified key. If it is the last key, it removes the mapping
* altogether.
*
* @param key Key whose members will have the value removed.
* @param member Value to remove from the set of members assigned
* to the key.
* @return true if the value was in the set of
* members for the key.
*/
public boolean removeMember(K key, M member) {
if (!containsKey(key)) return false;
boolean result = get(key).remove(member);
if (get(key).size() == 0)
remove(key);
return result;
}
/**
* Adds a set of members to the value of the set mapped to by
* the specified key.
*
* @param key Key whose set value will have the object.
* @param values Values to add to the set picked out by the key.
*/
public void addMembers(K key, Set values) {
Set memberSet = get(key);
if (memberSet == null)
put(key,new HashSet(values));
else
memberSet.addAll(values);
}
/**
* Returns a set constituting the union of all of the members of
* the set values for all of the keys.
*
* @return The union of the members of the set values.
*/
public Set memberValues() {
Set set = new HashSet();
for (Set members : values())
set.addAll(members);
return set;
}
/**
* Returns the set of values for the specified key, or the empty
* set if there have been none added. This behavior only differs
* from the basic {@link #get(Object)} method in that it returns the
* empty set rather than null.
*/
public Set getSet(K key) {
Set result = get(key);
return result != null
? result
: new HashSet(0);
}
}