de.alpharogroup.collections

Class InsertionOrderMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

java.util.LinkedHashMap<K,V>

de.alpharogroup.collections.InsertionOrderMap<K,V>

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

All Implemented Interfaces:

Serializable, Cloneable, Map<K,V>

public class InsertionOrderMap<K,V>
extends LinkedHashMap<K,V>

This class overwrites the put-method from the LinkedHashMap. That inserts the value to the right order it was inserted in the Map. Note that the difference in the LinkedHashMap is the order does not change if we put the same key with a new value. In this class the order changes when we put a new value with the same key.

Version:

1.0

Author:

Asterios Raptis

See Also:

LinkedHashMap, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

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

Constructor Summary

Constructors

Constructor and Description
InsertionOrderMap() Constructs an empty insertion-ordered InsertionOrderMap instance with a default capacity (16) and load factor (0.75).
InsertionOrderMap(int initialCapacity) Constructs an empty insertion-ordered InsertionOrderMap instance with the specified initial capacity and a default load factor (0.75).
InsertionOrderMap(int initialCapacity, float loadFactor) Constructs an empty insertion-ordered InsertionOrderMap instance with the specified initial capacity and load factor.
InsertionOrderMap(int initialCapacity, float loadFactor, boolean accessOrder) Constructs an empty InsertionOrderMap instance with the specified initial capacity, load factor and ordering mode.
InsertionOrderMap(Map<? extends K,? extends V> m) Constructs an insertion-ordered InsertionOrderMap instance with the same mappings as the specified map.

Method Summary

Modifier and Type	Method and Description
V	put(K key, V value) Associates the specified value with the specified key in this map.

Methods inherited from class java.util.LinkedHashMap

clear, containsValue, entrySet, forEach, get, getOrDefault, keySet, removeEldestEntry, replaceAll, values

Methods inherited from class java.util.HashMap

clone, compute, computeIfAbsent, computeIfPresent, containsKey, isEmpty, merge, putAll, putIfAbsent, remove, remove, replace, replace, size

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, containsKey, equals, hashCode, isEmpty, merge, putAll, putIfAbsent, remove, remove, replace, replace, size

Constructor Detail

InsertionOrderMap

public InsertionOrderMap()

Constructs an empty insertion-ordered InsertionOrderMap instance with a default capacity (16) and load factor (0.75).

InsertionOrderMap

public InsertionOrderMap(int initialCapacity)

Constructs an empty insertion-ordered InsertionOrderMap instance with the specified initial capacity and a default load factor (0.75).

Parameters:

initialCapacity - the initial capacity.

Throws:

IllegalArgumentException - if the initial capacity is negative.

InsertionOrderMap

public InsertionOrderMap(int initialCapacity,
                         float loadFactor)

Constructs an empty insertion-ordered InsertionOrderMap instance with the specified initial capacity and load factor.

Parameters:

initialCapacity - the initial capacity.

loadFactor - the load factor.

Throws:

IllegalArgumentException - if the initial capacity is negative or the load factor is nonpositive.

InsertionOrderMap

public InsertionOrderMap(int initialCapacity,
                         float loadFactor,
                         boolean accessOrder)

Constructs an empty InsertionOrderMap instance with the specified initial capacity, load factor and ordering mode.

Parameters:

initialCapacity - the initial capacity.

loadFactor - the load factor.

accessOrder - the ordering mode - true for access-order, false for insertion-order.

Throws:

IllegalArgumentException - if the initial capacity is negative or the load factor is nonpositive.

InsertionOrderMap

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

Constructs an insertion-ordered InsertionOrderMap instance with the same mappings as the specified map. The InsertionOrderMap instance is created with a a default load factor (0.75) and an initial capacity sufficient to hold the mappings in the specified map.

Parameters:

m - the map whose mappings are to be placed in this map.

Throws:

NullPointerException - if the specified map is null.

Method Detail

put

public V put(K key,
             V value)

Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is removed and then insert new with the same key and the new value. That inserts the value to the right order it was inserted in the Map. Note that the difference in the LinkedHashMap is the order does not change if we put the same key with a new value. In this class the order changes when we put a new value with the same key.

Specified by:

put in interface Map<K,V>

Overrides:

put in class HashMap<K,V>

Parameters:

key - key with which the specified value is to be associated.

value - value to be associated with the specified key.

Returns:

previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the HashMap previously associated null with the specified key.