Package edu.stanford.nlp.util

Class Maps

java.lang.Object

edu.stanford.nlp.util.Maps

public class Maps
extends Object

Utilities for Maps, including inverting, composing, and support for list/set values.

Author:

Dan Klein (klein@cs.stanford.edu)

Method Summary

Modifier and Type	Method	Description
static <K,V1,V2> void	addAll(Map<K,V1> to, Map<K,V2> from, Function<V2,V1> function)	Adds all of the keys in from to to, applying function to the values to transform them from V2 to V1.
static <X,Y,Z> Map<X,Z>	compose(Map<X,Y> map1, Map<Y,Z> map2)	Compose two maps map1:x->y and map2:y->z to get a map x->z
static <T,V> Map<T,V>	getAll(Map<T,V> map, Collection<T> indices)	get all values corresponding to the indices (if they exist in the map)
static boolean	getBool(Map<String,String> props, String key)	Load a boolean property from a Map.
static boolean	getBool(Map<String,String> props, String key, boolean defaultValue)	Load a boolean property from a Map.
static <X,Y> Map<Y,X>	invert(Map<X,Y> map)	Inverts a map x->y to a map y->x assuming unique preimages.
static <X,Y> Map<Y,Set<X>>	invertSet(Map<X,Y> map)	Inverts a map x->y to a map y->pow(x) not assuming unique preimages.
static void	main(String[] args)
static <K,V> void	putIntoValueArrayList(Map<K,List<V>> map, K key, V value)	Adds the value to the ArrayList given by map.get(key), creating a new ArrayList if needed.
static <K,V,C extends Collection<V>> void	putIntoValueCollection(Map<K,C> map, K key, V value, CollectionFactory<V> cf)	Adds the value to the collection given by map.get(key).
static <K,V> void	putIntoValueHashSet(Map<K,Set<V>> map, K key, V value)	Adds the value to the HashSet given by map.get(key), creating a new HashMap if needed.
static <K,V> void	removeKeys(Map<K,V> map, Collection<K> removekeys)	Removes keys from the map
static <K extends Comparable<? super K>,V> List<Map.Entry<K,V>>	sortedEntries(Collection<Map.Entry<K,V>> entries)	Sorts a list of entries.
static <K extends Comparable<? super K>,V> List<Map.Entry<K,V>>	sortedEntries(Map<K,V> map)	Returns a List of entries in the map, sorted by key.
static <T,V> String	toString(Map<T,V> map, String preAppend, String postAppend, String keyValSeparator, String itemSeparator)	Pretty print a Counter.
static <K extends Comparable<K>,V> String	toStringSorted(Map<K,V> map)	Stringifies a Map in a stable fashion.
static <K extends Comparable<K>,V> void	toStringSorted(Map<K,V> map, StringBuilder builder)	Stringifies a Map in a stable fashion.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

putIntoValueHashSet

public static <K,V> void putIntoValueHashSet(Map<K,Set<V>> map,
                                                   K key,
                                                   V value)

Adds the value to the HashSet given by map.get(key), creating a new HashMap if needed.

putIntoValueArrayList

public static <K,V> void putIntoValueArrayList(Map<K,List<V>> map,
                                                     K key,
                                                     V value)

Adds the value to the ArrayList given by map.get(key), creating a new ArrayList if needed.

putIntoValueCollection

public static <K,V,C extends Collection<V>> void putIntoValueCollection(Map<K,C> map,
                                                                                    K key,
                                                                                    V value,
                                                                                    CollectionFactory<V> cf)

Adds the value to the collection given by map.get(key). A new collection is created using the supplied CollectionFactory.

compose

public static <X,Y,Z> Map<X,Z> compose(Map<X,Y> map1,
                                                         Map<Y,Z> map2)

Compose two maps map1:x->y and map2:y->z to get a map x->z

Returns:

The composed map

invert

public static <X,Y> Map<Y,X> invert(Map<X,Y> map)

Inverts a map x->y to a map y->x assuming unique preimages. If they are not unique, you get an arbitrary ones as the values in the inverted map.

Returns:

The inverted map

invertSet

public static <X,Y> Map<Y,Set<X>> invertSet(Map<X,Y> map)

Inverts a map x->y to a map y->pow(x) not assuming unique preimages.

Returns:

The inverted set

sortedEntries

public static <K extends Comparable<? super K>,V> List<Map.Entry<K,V>> sortedEntries(Collection<Map.Entry<K,V>> entries)

Sorts a list of entries. This method is here since the entries might come from a Counter.

sortedEntries

public static <K extends Comparable<? super K>,V> List<Map.Entry<K,V>> sortedEntries(Map<K,V> map)

Returns a List of entries in the map, sorted by key.

toStringSorted

public static <K extends Comparable<K>,V> void toStringSorted(Map<K,V> map,
                                                                    StringBuilder builder)

Stringifies a Map in a stable fashion.

toStringSorted

public static <K extends Comparable<K>,V> String toStringSorted(Map<K,V> map)

Stringifies a Map in a stable fashion.

removeKeys

public static <K,V> void removeKeys(Map<K,V> map,
                                          Collection<K> removekeys)

Removes keys from the map

addAll

public static <K,V1,V2> void addAll(Map<K,V1> to,
                                                Map<K,V2> from,
                                                Function<V2,V1> function)

Adds all of the keys in from to to, applying function to the values to transform them from V2 to V1.

getAll

public static <T,V> Map<T,V> getAll(Map<T,V> map,
                                                Collection<T> indices)

get all values corresponding to the indices (if they exist in the map)

Parameters:

map -

indices -

Returns:

a submap corresponding to the indices

getBool

public static boolean getBool(Map<String,String> props,
                              String key)

Load a boolean property from a Map. If the key is not present, returns false.

getBool

public static boolean getBool(Map<String,String> props,
                              String key,
                              boolean defaultValue)

Load a boolean property from a Map. If the key is not present, returns defaultValue.

toString

public static <T,V> String toString(Map<T,V> map,
                                          String preAppend,
                                          String postAppend,
                                          String keyValSeparator,
                                          String itemSeparator)

Pretty print a Counter. This one has more flexibility in formatting, and doesn't sort the keys.

main

public static void main(String[] args)