Package io.github.classgraph.utils

Class SingletonMap<K,V>

java.lang.Object

io.github.classgraph.utils.SingletonMap<K,V>

Type Parameters:

K - The key type.

V - The value type.

public abstract class SingletonMap<K,V>
extends Object

A map from keys to singleton instances.

Constructor Summary

Constructors

Constructor	Description
SingletonMap()

Method Summary

Modifier and Type	Method	Description
void	clear()	Clear the map.
boolean	createSingleton(K key, LogNode log)	Initialize a value object for this key and return true, if this is the first time this key has been seen, otherwise return false.
V	get(K key)	Get the singleton for a given key.
V	getOrCreateSingleton(K key, LogNode log)	Check if the given key is in the map, and if so, return it.
abstract V	newInstance(K key, LogNode log)	Construct a new singleton instance.
List<V>	values()	Get all singletons in the map.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingletonMap

public SingletonMap()

Method Detail

createSingleton

public boolean createSingleton(K key,
                               LogNode log)
                        throws Exception

Initialize a value object for this key and return true, if this is the first time this key has been seen, otherwise return false.

Parameters:

key - The key for the singleton.

log - The log.

Returns:

The singleton instance.

Throws:

Exception - if newInstance(key) throws an exception.

IllegalArgumentException - if newInstance(key) returns null.

getOrCreateSingleton

public V getOrCreateSingleton(K key,
                              LogNode log)
                       throws Exception

Check if the given key is in the map, and if so, return it. If not, create a singleton value for that key, and return the created value.

Parameters:

key - The key for the singleton.

log - The log.

Returns:

The singleton instance.

Throws:

Exception - if newInstance(key) throws an exception.

IllegalArgumentException - if newInstance(key) returns null.

newInstance

public abstract V newInstance(K key,
                              LogNode log)
                       throws Exception

Construct a new singleton instance.

Parameters:

key - The key for the singleton.

log - The log.

Returns:

The singleton instance.

Throws:

Exception - If something goes wrong.

get

public V get(K key)
      throws InterruptedException

Get the singleton for a given key.

Parameters:

key - The key for the singleton.

Returns:

the new singleton instance, initialized by calling newInstance, or null if createSingleton() or getOrCreateSingleton() has not yet been called. Also returns null if newInstance() threw an exception or returned null while calling either of these methods.

Throws:

InterruptedException - If getting the singleton was interrupted.

values

public List<V> values()
               throws InterruptedException

Get all singletons in the map.

Returns:

the singleton values in the map.

Throws:

InterruptedException - If getting the values was interrupted.

clear

public void clear()

Clear the map.