org.incava.ijdk.collect

Class Hash<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

org.incava.ijdk.collect.Hash<K,V>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.util.Map.Entry<K,V>>, java.util.Map<K,V>

public class Hash<K,V>
extends java.util.HashMap<K,V>
implements java.lang.Iterable<java.util.Map.Entry<K,V>>

A mapping from keys, via hashCode to values. The name "Hash" is taken from the equivalent class in Ruby, and avoids name collision with the existing java.util.Map.

See Also:

Serialized Form

Nested Class Summary

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

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

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

java.util.Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
static long	serialVersionUID

Constructor Summary

Constructors

Constructor and Description
Hash() Creates an empty IJDK map.
Hash(java.util.List<Pair<K,V>> elements) Creates a map from a list of pairs.
Hash(java.util.Map<K,V> other) Creates a IJDK map from a JDK one.

Method Summary

Modifier and Type	Method and Description
static <KeyType,ValueType> Hash<KeyType,ValueType>	empty() Creates an empty hash map.
java.util.Set<java.util.Map.Entry<K,V>>	entries() Returns the entries, the same as entrySet.
V	fetch(K key) Returns the value for the given entry.
V	fetch(K key, V defValue) Returns the value for the given entry.
java.util.Iterator<java.util.Map.Entry<K,V>>	iterator() Returns an iterator over the entries, so this map can be used as an iterable in a for-each block:
java.util.Set<K>	keys() Returns the keys, the same as keySet.
static <KeyType,ValueType> Hash<KeyType,ValueType>	of() Creates an empty hash map.
static <Type> Hash<Type,Type>	of(Array<Type> array) Creates a map from an Array.
static <KeyType,ValueType> Hash<KeyType,ValueType>	of(KeyType k1, ValueType v1) Creates a map with one key/value pair.
static <KeyType,ValueType> Hash<KeyType,ValueType>	of(KeyType k1, ValueType v1, KeyType k2, ValueType v2) Creates a map with two key/value pairs.
static <KeyType,ValueType> Hash<KeyType,ValueType>	of(KeyType k1, ValueType v1, KeyType k2, ValueType v2, KeyType k3, ValueType v3) Creates a map with three key/value pairs.
static <KeyType,ValueType> Hash<KeyType,ValueType>	of(java.util.List<Pair<KeyType,ValueType>> list) Creates a map from a list of pairs.
Hash<K,V>	set(K key, V value) Adds or replaces the value for the given key, either of which can be null.

Methods inherited from class java.util.HashMap

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

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.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.Map

equals, hashCode

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

Hash

public Hash(java.util.List<Pair<K,V>> elements)

Creates a map from a list of pairs.

Parameters:

elements - the keys and values for the map.

Hash

public Hash(java.util.Map<K,V> other)

Creates a IJDK map from a JDK one. The new map is non-backing to the old one.

Parameters:

other - the JDK map from which to populate this one

Hash

public Hash()

Creates an empty IJDK map.

Method Detail

of

public static <KeyType,ValueType> Hash<KeyType,ValueType> of()

Creates an empty hash map.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Returns:

an empty map

See Also:

empty()

empty

public static <KeyType,ValueType> Hash<KeyType,ValueType> empty()

Creates an empty hash map.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Returns:

an empty map

of

public static <KeyType,ValueType> Hash<KeyType,ValueType> of(KeyType k1,
                                                             ValueType v1)

Creates a map with one key/value pair.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Parameters:

k1 - the first parameter

v1 - the first value

Returns:

the new Map

of

public static <KeyType,ValueType> Hash<KeyType,ValueType> of(KeyType k1,
                                                             ValueType v1,
                                                             KeyType k2,
                                                             ValueType v2)

Creates a map with two key/value pairs.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Parameters:

k1 - the first parameter

v1 - the first value

k2 - the second parameter

v2 - the second value

Returns:

the new Map

of

public static <KeyType,ValueType> Hash<KeyType,ValueType> of(KeyType k1,
                                                             ValueType v1,
                                                             KeyType k2,
                                                             ValueType v2,
                                                             KeyType k3,
                                                             ValueType v3)

Creates a map with three key/value pairs.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Parameters:

k1 - the first parameter

v1 - the first value

k2 - the second parameter

v2 - the second value

k3 - the third parameter

v3 - the third value

Returns:

the new Map

of

public static <KeyType,ValueType> Hash<KeyType,ValueType> of(java.util.List<Pair<KeyType,ValueType>> list)

Creates a map from a list of pairs.

Type Parameters:

KeyType - the type of keys of the map

ValueType - the type of values of the map

Parameters:

list - the list from which to populate the new map

Returns:

the new Map

of

public static <Type> Hash<Type,Type> of(Array<Type> array)

Creates a map from an Array.

Type Parameters:

Type - the type of keys and values of the map

Parameters:

array - the array from which to populate the new map

Returns:

the new Map

set

public Hash<K,V> set(K key,
                     V value)

Adds or replaces the value for the given key, either of which can be null. Returns the map, so this can be chained, in the form m.set("x", 1).set("y", 2).set("z", 3).

Parameters:

key - the key

value - the value

Returns:

this map, updated

keys

public java.util.Set<K> keys()

Returns the keys, the same as keySet.

Returns:

the keys as a set

entries

public java.util.Set<java.util.Map.Entry<K,V>> entries()

Returns the entries, the same as entrySet.

Returns:

the entries as a set

iterator

public java.util.Iterator<java.util.Map.Entry<K,V>> iterator()

Returns an iterator over the entries, so this map can be used as an iterable in a for-each block:

 Hash<String, Integer> map = Hash.<String, Integer>of("one", 1, "two", 2);
 for (Map.Entry<String, Integer> it : map) {
     // use it.getKey(), it.getValue()
 }
 

Specified by:

iterator in interface java.lang.Iterable<java.util.Map.Entry<K,V>>

Returns:

the entries as a set

fetch

public V fetch(K key,
               V defValue)

Returns the value for the given entry. If there is no such entry, then the default value is returned.

Parameters:

key - the key

defValue - the value to use if there is no entry for key

Returns:

the value or defValue

fetch

public V fetch(K key)

Returns the value for the given entry. If there is no such entry, then an IllegalArgumentException is thrown.

Parameters:

key - the key

Returns:

the value or defValue

Throws:

java.lang.IllegalArgumentException - if there is no such key