net.pwall.util

Class ListMap<K,V>

java.lang.Object

net.pwall.util.ListMap<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

Serializable, Map<K,V>

Direct Known Subclasses:

SortedListMap

public class ListMap<K,V>
extends Object
implements Map<K,V>, Serializable

An implementation of Map that uses a List to hold the entries, retaining the order of insertion. This class is useful when the order of insertion of entries is significant, but it suffers from serious performance degradation when the numbers of entries exceeds a handful.

Author:

Peter Wall

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ListMap.Entry<KK,VV> Inner class to represent a key-value pair in the ListMap.

Field Summary

Fields

Modifier and Type	Field and Description
protected List<ListMap.Entry<K,V>>	list

Constructor Summary

Constructors

Constructor and Description
ListMap() Construct an empty ListMap.
ListMap(int capacity) Construct an empty ListMap with a specified initial capacity.
ListMap(Map<? extends K,? extends V> m) Construct a ListMap with the contents of another Map.

Method Summary

Modifier and Type	Method and Description
void	clear() Remove all members from this ListMap.
boolean	containsKey(Object key) Test whether the ListMap contains a specified key.
boolean	containsValue(Object value) Test whether the ListMap contains the specified value.
Set<Map.Entry<K,V>>	entrySet() Get a Set of the key-value pairs in use in the ListMap.
boolean	equals(Object other) Compare this ListMap with another object for equality.
protected int	findIndex(Object key) Find the index for the specified key.
V	get(Object key) Get a value from the ListMap.
ListMap.Entry<K,V>	getEntry(int index) Get an ListMap.Entry by index.
int	hashCode() Get the hash code for this ListMap.
boolean	isEmpty() Test whether the ListMapis empty.
Set<K>	keySet() Get a Set representing the keys in use in the ListMap.
V	put(K key, V value) Store a value in the ListMap with the specified key.
void	putAll(Map<? extends K,? extends V> m) Add all the members of another Map to this ListMap.
V	remove(Object key) Remove the specified key-value mapping from the ListMap.
int	size() Get the number of values in the ListMap.
String	toString() Convert the map to String (usually for diagnostic purposes).
Collection<V>	values() Get a Collection of the values in the ListMap.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

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

Field Detail

list

protected List<ListMap.Entry<K,V>> list

Constructor Detail

ListMap

public ListMap()

Construct an empty ListMap.

ListMap

public ListMap(int capacity)

Construct an empty ListMap with a specified initial capacity.

Parameters:

capacity - the initial capacity

ListMap

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

Construct a ListMap with the contents of another Map.

Parameters:

m - the other Map

Method Detail

get

public V get(Object key)

Get a value from the ListMap.

Specified by:

get in interface Map<K,V>

Parameters:

key - the key of the value

Returns:

the value, or null if not found

See Also:

Map.get(Object)

containsKey

public boolean containsKey(Object key)

Test whether the ListMap contains a specified key.

Specified by:

containsKey in interface Map<K,V>

Parameters:

key - the key to test for

Returns:

true if the key is found

See Also:

Map.containsKey(Object)

put

public V put(K key,
             V value)

Store a value in the ListMap with the specified key.

Specified by:

put in interface Map<K,V>

Parameters:

key - the key

value - the value

Returns:

the previous value stored with that key, or null if no previous value

See Also:

Map.put(Object, Object)

remove

public V remove(Object key)

Remove the specified key-value mapping from the ListMap.

Specified by:

remove in interface Map<K,V>

Parameters:

key - the key

Returns:

the value stored with that key, or null if key not used

See Also:

Map.remove(Object)

size

public int size()

Get the number of values in the ListMap.

Specified by:

size in interface Map<K,V>

Returns:

the number of values

See Also:

Map.size()

isEmpty

public boolean isEmpty()

Test whether the ListMapis empty.

Specified by:

isEmpty in interface Map<K,V>

Returns:

true if the ListMap is empty

See Also:

Map.isEmpty()

containsValue

public boolean containsValue(Object value)

Test whether the ListMap contains the specified value.

Specified by:

containsValue in interface Map<K,V>

Parameters:

value - the value

Returns:

true if the ListMap contains the value

See Also:

Map.containsValue(Object)

putAll

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

Add all the members of another Map to this ListMap.

Specified by:

putAll in interface Map<K,V>

Parameters:

m - the other Map

See Also:

Map.putAll(Map)

clear

public void clear()

Remove all members from this ListMap.

Specified by:

clear in interface Map<K,V>

See Also:

Map.clear()

keySet

public Set<K> keySet()

Get a Set representing the keys in use in the ListMap.

Specified by:

keySet in interface Map<K,V>

Returns:

the Set of keys

See Also:

Map.keySet()

values

public Collection<V> values()

Get a Collection of the values in the ListMap.

Specified by:

values in interface Map<K,V>

Returns:

the Collection of values

See Also:

Map.values()

entrySet

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

Get a Set of the key-value pairs in use in the ListMap.

Specified by:

entrySet in interface Map<K,V>

Returns:

the Set of key-value pairs

See Also:

Map.entrySet()

hashCode

public int hashCode()

Get the hash code for this ListMap.

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class Object

Returns:

the hash code

See Also:

Object.hashCode()

equals

public boolean equals(Object other)

Compare this ListMap with another object for equality.

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class Object

Parameters:

other - the other object

Returns:

true if the other object is a ListMap and is identical to this object

See Also:

Object.equals(Object)

toString

public String toString()

Convert the map to String (usually for diagnostic purposes).

Overrides:

toString in class Object

Returns:

a string in the form {key=value, ...}

getEntry

public ListMap.Entry<K,V> getEntry(int index)

Get an ListMap.Entry by index.

Parameters:

index - the index

Returns:

the list entry

findIndex

protected int findIndex(Object key)

Find the index for the specified key.

Parameters:

key - the key

Returns:

the index for this key, or -1 if not found