ariba.util.core
Class ReadOnlyMap<K,V>

java.lang.Object
  ariba.util.core.ReadOnlyMap<K,V>

Direct Known Subclasses:

WriteResistantMap

public class ReadOnlyMap<K,V>
extends Object

A Map-like object that can't be modified - not because it is immutable (which would raise a run-time exception), but because it has no API for modifying it. In a better world, it could be defined as a superinterface of Map. A ReadOnlyMap wraps an ordinary Map, which may contain other maps as values (i.e., the Map may be nested). In that case, when returning a value that is a Map, the ReadOnlyMap wraps that value in another ReadOnlyMap, so that IT can't be modified, either. The wrapping doesn't extend to values of other types, unfortunately, but it is at least a good start toward getting a declarative, statically-enforced, read-only data structure.

Nested Class Summary

class

ReadOnlyMap.Entry<K,V>

Field Summary

static char

Dot

Constructor Summary

ReadOnlyMap(Map<K,V> aMap)

Method Summary

boolean	containsKey(K key)
boolean	containsValue(V value)
static ReadOnlyMap	emptyInstance()
Set	entrySet()
boolean	equals(Object o)
V	get(K key)
Object	getPath(String path) Fetch a value from a nested map using a path of keys using dot notation.
int	hashCode()
Map<K,V>	immutableMap()
static Map	immutableMap(ReadOnlyMap roMap)
boolean	isEmpty()
static <K,V> boolean	isNullOrEmpty(ReadOnlyMap<K,V> m)
Set<K>	keySet()
Map<K,V>	mapCopy() Get a copy of the underlying Map.
static Map	mapCopy(ReadOnlyMap roMap) Get a copy of the underlying Map.
int	size()
String	toString()
Collection<V>	values()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

Dot

public static final char Dot

See Also:

Constant Field Values

Constructor Detail

ReadOnlyMap

public ReadOnlyMap(Map<K,V> aMap)

Method Detail

emptyInstance

public static ReadOnlyMap emptyInstance()

get

public V get(K key)

containsKey

public boolean containsKey(K key)

containsValue

public boolean containsValue(V value)

equals

public boolean equals(Object o)

Overrides:

equals in class Object

isEmpty

public boolean isEmpty()

isNullOrEmpty

public static <K,V> boolean isNullOrEmpty(ReadOnlyMap<K,V> m)

size

public int size()

keySet

public Set<K> keySet()

values

public Collection<V> values()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

entrySet

public Set entrySet()

getPath

public Object getPath(String path)

Fetch a value from a nested map using a path of keys using dot notation.

Parameters:

path - The dotted path of key values

Returns:

The value at that path. If the value is a Map, return a ReadOnlyMap, so the result is equivalent to doing a sequence of get operations on the path elements.

toString

public String toString()

Overrides:

toString in class Object

mapCopy

public Map<K,V> mapCopy()

Get a copy of the underlying Map. It's not the actual underlying Map, so is can't be used as a 'back door' to modify the state of the ReadOnlyMap. The static method mapCopy(ReadOnlyMap) is recommended unless the caller is certain that both this and the Map it encloses are non-null.

Returns:

A copy of the wrapped Map.

mapCopy

public static Map mapCopy(ReadOnlyMap roMap)

Get a copy of the underlying Map. It's not the actual underlying Map, so is can't be used as a 'back door' to modify the state of the ReadOnlyMap. If

Parameters:

roMap - The ReadOnlyMap to copy. Return null if roMap is null, or its enclosed Map is null or empty.

Returns:

A copy of the wrapped Map.

immutableMap

public Map<K,V> immutableMap()

immutableMap

public static Map immutableMap(ReadOnlyMap roMap)