xapi.collect.impl

Class AbstractInitMap<Key,Value>

java.lang.Object

xapi.collect.impl.AbstractInitMap<Key,Value>

Type Parameters:

Key - - The type of key to use. Be sure to implement hashCode() and equals().

Value - - The type of values provided.

All Implemented Interfaces:

Iterable<Map.Entry<String,Value>>, Dictionary<String,Value>, InitMap<Key,Value>, StringDictionary<Value>, ConvertsValue<Key,Value>

Direct Known Subclasses:

InitMapDefault

public abstract class AbstractInitMap<Key,Value>
extends Object
implements InitMap<Key,Value>

A map for singleton values; if containsKey(key) == true, the value is returned from the underlying ConcurrentHashMap, even if null. When a key is not present, the map will call InitMap.initialize(Object), which accepts the key as parameter, and return the singleton which will be set in the map. This map IS entirely threadsafe. The initialization process is guarded by a double-checked lock, which is ONLY checked in jre runtime environments, and only if the multithreading system property ("xapi.multithreaded") is set. If you set a value manually, InitMap.initialize(Object) will not be called for that key.

Author:

James X. Nelson (james@wetheinter.net)

Field Summary

Fields

Modifier and Type	Field and Description
protected static ConvertsValue	ALWAYS_NULL
static ConvertsValue<Class<?>,String>	CLASS_NAME
static ConvertsValue<String,String>	PASS_THRU
protected static ConvertsValue	TO_STRING A default toString converter that just calls String.valueOf.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractInitMap()
protected	AbstractInitMap(ConvertsValue<Key,String> keyProvider)

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(Key key)
Value	convert(Key from)
Value	get(Key k)
protected Object	getLock(Object forKey)
protected boolean	isMultiThreaded()
Value	put(Key key, Value value)
String	toKey(Key key) We force subclasses to deal with serializing keys to unique names, so javascript can implement this directly on an object, and you can achieve a degree of portability, by making map structure deterministic.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface xapi.collect.api.InitMap

initialize

Methods inherited from interface xapi.collect.api.Dictionary

clearValues, forKeys, getValue, hasKey, removeValue, setValue

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

Field Detail

TO_STRING

protected static final ConvertsValue TO_STRING

A default toString converter that just calls String.valueOf. This will return "null" for null. But, you weren't using "null" for an id anyway, were you?

PASS_THRU

public static final ConvertsValue<String,String> PASS_THRU

CLASS_NAME

public static final ConvertsValue<Class<?>,String> CLASS_NAME

ALWAYS_NULL

protected static final ConvertsValue ALWAYS_NULL

Constructor Detail

AbstractInitMap

protected AbstractInitMap()

AbstractInitMap

protected AbstractInitMap(ConvertsValue<Key,String> keyProvider)

Method Detail

get

public Value get(Key k)

Specified by:

get in interface InitMap<Key,Value>

put

public Value put(Key key,
                 Value value)

Specified by:

put in interface InitMap<Key,Value>

containsKey

public boolean containsKey(Key key)

Specified by:

containsKey in interface InitMap<Key,Value>

isMultiThreaded

protected boolean isMultiThreaded()

getLock

protected Object getLock(Object forKey)

toKey

public String toKey(Key key)

Description copied from interface: InitMap

We force subclasses to deal with serializing keys to unique names, so javascript can implement this directly on an object, and you can achieve a degree of portability, by making map structure deterministic.

Specified by:

toKey in interface InitMap<Key,Value>

Parameters:

key - - A key of whatever type you want. Use Pair or Triple to overload.

Returns:

- A unique key for dictionary-like sematics try to have a string id pre-constructed; if your object fields are immutable, you can safely construct the id, and never have to null check.

convert

public Value convert(Key from)

Specified by:

convert in interface ConvertsValue<Key,Value>

Parameters:

from - - An object to convert

Returns:

- The result of the conversion