Package groovy.lang

Class MapWithDefault<K,V>

java.lang.Object

groovy.lang.MapWithDefault<K,V>

All Implemented Interfaces:

Map<K,V>

public final class MapWithDefault<K,V>
extends Object
implements Map<K,V>

A wrapper for Map which allows a default value to be specified using a closure. Normally not instantiated directly but used via the DGM withDefault method.

Since:

1.7.1

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Method Summary

Modifier and Type	Method	Description
void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()
boolean	equals(Object obj)
V	get(Object key)	Returns the value to which the specified key is mapped, or the default value as specified by the initializing closure if this map contains no mapping for the key.
int	hashCode()
boolean	isEmpty()
Set<K>	keySet()
static <K, V> Map<K,V>	newInstance(Map<K,V> m, boolean autoGrow, boolean autoShrink, Closure<V> initClosure)	Decorates the given Map allowing a default value to be specified.
static <K, V> Map<K,V>	newInstance(Map<K,V> m, Closure<V> initClosure)	Decorates the given Map allowing a default value to be specified.
V	put(K key, V value)	Associates the specified value with the specified key in this map.
void	putAll(Map<? extends K,? extends V> m)
V	remove(Object key)
int	size()
Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Method Details

newInstance

public static <K,
V> Map<K,V> newInstance(Map<K,V> m,
 Closure<V> initClosure)

Decorates the given Map allowing a default value to be specified.

Parameters:

m - a Map to wrap

initClosure - the closure which when passed the key returns the default value

Returns:

the wrapped Map

newInstance

public static <K,
V> Map<K,V> newInstance(Map<K,V> m,
 boolean autoGrow,
 boolean autoShrink,
 Closure<V> initClosure)

Decorates the given Map allowing a default value to be specified. Allows the behavior to be configured using autoGrow and autoShrink parameters. The value of autoShrink doesn't alter any values in the initial wrapped map, but you can start with an empty map and use putAll if you really need the minimal backing map value.

Parameters:

m - a Map to wrap

autoGrow - when true, also mutate the map adding in this value; otherwise, don't mutate the map, just return to calculated value

autoShrink - when true, ensure the key will be removed if attempting to store the default value using put or putAll

initClosure - the closure which when passed the key returns the default value

Returns:

the wrapped Map

Since:

4.0.1

size

public int size()

Specified by:

size in interface Map<K,V>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

get

public V get(Object key)

Returns the value to which the specified key is mapped, or the default value as specified by the initializing closure if this map contains no mapping for the key. If autoGrow is true and the initializing closure is called, the map is modified to contain the new key and value so that the calculated value is effectively cached if needed again. Otherwise, the map will be unchanged.

Specified by:

get in interface Map<K,V>

put

public V put(K key,
 V value)

Associates the specified value with the specified key in this map. If autoShrink is true, the initializing closure is called and if it evaluates to the value being stored, the value will not be stored and indeed any existing value will be removed. This can be useful when trying to keep the memory requirements small for large key sets where only a spare number of entries differ from the default.

Specified by:

put in interface Map<K,V>

Returns:

the previous value associated with key if any, otherwise null.

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> m)

Specified by:

putAll in interface Map<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

equals

public boolean equals(Object obj)

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class Object

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class Object