com.jn.langx.util.collection

类 NonAbsentHashMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

com.jn.langx.util.collection.NonAbsentHashMap<K,V>

类型参数:

K - key

V - value

所有已实现的接口:

Serializable, Cloneable, Map<K,V>

public class NonAbsentHashMap<K,V>
extends HashMap<K,V>

Avoid the follower code:

     Map> map = new HashMap>();
     List list = map.get(key);
     if(list==null){
         list = new ArrayList();
         map.put(key, list);
     }
     list.add(e);
 

using this class, your code will be:

     Supplier> supplier = new Supplier>(){
         public List get(K key){
             return new ArrayList();
         }
     };
     Map> map = new NonAbsentHashMap>();
     map.get(key).add(e);
 

另请参阅:

Map, HashMap, WrappedNonAbsentMap, 序列化表格

嵌套类概要

从类继承的嵌套类/接口 java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

从接口继承的嵌套类/接口 java.util.Map

Map.Entry<K,V>

构造器概要

构造器

构造器和说明
NonAbsentHashMap(int initialCapacity, float loadFactor, Supplier<K,V> supplier)
NonAbsentHashMap(int initialCapacity, Supplier<K,V> supplier)
NonAbsentHashMap(Map<? extends K,? extends V> m, Supplier<K,V> supplier)
NonAbsentHashMap(Supplier<K,V> supplier)

方法概要

限定符和类型	方法和说明
V	get(Object key)
V	get(Object key, Supplier<K,V> supplier)
V	getIfPresent(Object key)
V	putIfAbsent(K key, V value)

从类继承的方法 java.util.HashMap

clear, clone, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, forEach, getOrDefault, isEmpty, keySet, merge, put, putAll, remove, remove, replace, replace, replaceAll, size, values

从类继承的方法 java.util.AbstractMap

equals, hashCode, toString

从类继承的方法 java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 java.util.Map

equals, hashCode

构造器详细资料

NonAbsentHashMap

public NonAbsentHashMap(@NonNull
                        Supplier<K,V> supplier)

NonAbsentHashMap

public NonAbsentHashMap(int initialCapacity,
                        Supplier<K,V> supplier)

NonAbsentHashMap

public NonAbsentHashMap(int initialCapacity,
                        float loadFactor,
                        @NonNull
                        Supplier<K,V> supplier)

NonAbsentHashMap

public NonAbsentHashMap(Map<? extends K,? extends V> m,
                        Supplier<K,V> supplier)

方法详细资料

get

public V get(Object key,
             Supplier<K,V> supplier)

get

public V get(Object key)

指定者:

get 在接口中 Map<K,V>

覆盖:

get 在类中 HashMap<K,V>

getIfPresent

public V getIfPresent(Object key)

putIfAbsent

public V putIfAbsent(K key,
                     V value)

指定者:

putIfAbsent 在接口中 Map<K,V>

覆盖:

putIfAbsent 在类中 HashMap<K,V>