Modifier and Type	Class and Description
public static class	SingletonMap.NewInstanceException Thrown when `SingletonMap#newInstance(Object, LogNode)` throws an exception.
public static interface	SingletonMap.NewInstanceFactory< The instance type. V, E extends Exception> Create a new instance.
public static class	SingletonMap.NullSingletonException Thrown when `SingletonMap#newInstance(Object, LogNode)` returns null.
private static class	SingletonMap.SingletonHolder< the singleton type V> Wrapper to allow an object instance to be put into a ConcurrentHashMap using putIfAbsent() without requiring the instance to be initialized first, so that putIfAbsent can be performed without wrapping it with a synchronized lock, and so that initialization work is not wasted if an object is already in the map for the key.

Modifier and Type	Field and Description
private final ConcurrentMap<K, SingletonMap.SingletonHolder<V>>	map The map.

Access	Constructor and Description
public	SingletonMap()

Method Summary

Modifier and Type	Method and Description
public void	clear() Clear the map.
public List<Map.Entry<K, V>>	Returns: the map entries. entries() Get the map entries.
public V	Returns: The non-null singleton instance, if `newInstance(Object, LogNode)` returned a non-null instance on this call or a previous call, otherwise throws `NullPointerException` if this call or a previous call to `newInstance(Object, LogNode)` returned null. get(final K The key for the singleton. key, final LogNode The log. log, final SingletonMap.NewInstanceFactory<V, E> if non-null, a factory for creating new instances, otherwise if null, then `newInstance(Object, LogNode)` is called instead (this allows new instance creation to be overridden on a per-instance basis). newInstanceFactory) Check if the given key is in the map, and if so, return the value of `newInstance(Object, LogNode)` for that key, or block on the result of `newInstance(Object, LogNode)` if another thread is currently creating the new instance.
public V	Returns: The non-null singleton instance, if `newInstance(Object, LogNode)` returned a non-null instance on this call or a previous call, otherwise throws `NullPointerException` if this call or a previous call to `newInstance(Object, LogNode)` returned null. get(final K The key for the singleton. key, final LogNode The log. log) Check if the given key is in the map, and if so, return the value of `newInstance(Object, LogNode)` for that key, or block on the result of `newInstance(Object, LogNode)` if another thread is currently creating the new instance.
public boolean	Returns: true, if the map is empty isEmpty() Returns true if the map is empty.
public abstract V	Returns: The singleton instance. This method must either return a non-null value, or throw an exception of type E. newInstance(K The key for the singleton. key, LogNode The log. log) Construct a new singleton instance.
public V	Returns: the old singleton from the map, if one was present, otherwise null. remove(final K the key key) Remove the singleton for a given key.
public List<V>	Returns: the singleton values in the map, skipping over any value for which newInstance() threw an exception or returned null. values() Get all valid singleton values in the map.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

map	back to summary
private final ConcurrentMap<K, SingletonMap.SingletonHolder<V>> map The map.

Constructor Detail

SingletonMap	back to summary
public SingletonMap()

Method Detail

clear	back to summary
public void clear() Clear the map.

entries	back to summary
public List<Map.Entry<K, V>> entries() throws InterruptedException Get the map entries. Returns:List<Map.Entry<K, V>> the map entries. Exceptions InterruptedException: if interrupted.

entries

back to summary

public List<Map.Entry<K, V>> entries() throws InterruptedException

Get the map entries.

Returns:List<Map.Entry<K, V>>

the map entries.

Exceptions

InterruptedException:: if interrupted.

get back to summary

get	back to summary
public V get(final K key, final LogNode log, final SingletonMap.NewInstanceFactory<V, E> newInstanceFactory) throws SingletonMap:E, InterruptedException, NullSingletonException, NewInstanceException Check if the given key is in the map, and if so, return the value of `newInstance(Object, LogNode)` for that key, or block on the result of `newInstance(Object, LogNode)` if another thread is currently creating the new instance. If the given key is not currently in the map, store a placeholder in the map for this key, then run `newInstance(Object, LogNode)` for the key, store the result in the placeholder (which unblocks any other threads waiting for the value), and then return the new instance. Parameters key:K The key for the singleton. log:LogNode The log. newInstanceFactory:SingletonMap.NewInstanceFactory<V, E> if non-null, a factory for creating new instances, otherwise if null, then `newInstance(Object, LogNode)` is called instead (this allows new instance creation to be overridden on a per-instance basis). Returns:V The non-null singleton instance, if `newInstance(Object, LogNode)` returned a non-null instance on this call or a previous call, otherwise throws `NullPointerException` if this call or a previous call to `newInstance(Object, LogNode)` returned null. Exceptions SingletonMap:E: If `newInstance(Object, LogNode)` threw an exception. InterruptedException: if the thread was interrupted while waiting for the singleton to be instantiated by another thread. NullSingletonException: if `newInstance(Object, LogNode)` returned null. NewInstanceException: if `newInstance(Object, LogNode)` threw an exception.

public V get(final K key, final LogNode log, final SingletonMap.NewInstanceFactory<V, E> newInstanceFactory) throws SingletonMap:E, InterruptedException, NullSingletonException, NewInstanceException

Check if the given key is in the map, and if so, return the value of newInstance(Object, LogNode) for that key, or block on the result of newInstance(Object, LogNode) if another thread is currently creating the new instance. If the given key is not currently in the map, store a placeholder in the map for this key, then run newInstance(Object, LogNode) for the key, store the result in the placeholder (which unblocks any other threads waiting for the value), and then return the new instance.

Parameters

key:K: The key for the singleton.
log:LogNode: The log.
newInstanceFactory:SingletonMap.NewInstanceFactory<V, E>: if non-null, a factory for creating new instances, otherwise if null, then newInstance(Object, LogNode) is called instead (this allows new instance creation to be overridden on a per-instance basis).

Returns:V

The non-null singleton instance, if newInstance(Object, LogNode) returned a non-null instance on this call or a previous call, otherwise throws NullPointerException if this call or a previous call to newInstance(Object, LogNode) returned null.

Exceptions

SingletonMap:E:: If newInstance(Object, LogNode) threw an exception.
InterruptedException:: if the thread was interrupted while waiting for the singleton to be instantiated by another thread.
NullSingletonException:: if newInstance(Object, LogNode) returned null.
NewInstanceException:: if newInstance(Object, LogNode) threw an exception.

get back to summary

get	back to summary
public V get(final K key, final LogNode log) throws SingletonMap:E, InterruptedException, NullSingletonException, NewInstanceException Check if the given key is in the map, and if so, return the value of `newInstance(Object, LogNode)` for that key, or block on the result of `newInstance(Object, LogNode)` if another thread is currently creating the new instance. If the given key is not currently in the map, store a placeholder in the map for this key, then run `newInstance(Object, LogNode)` for the key, store the result in the placeholder (which unblocks any other threads waiting for the value), and then return the new instance. Parameters key:K The key for the singleton. log:LogNode The log. Returns:V The non-null singleton instance, if `newInstance(Object, LogNode)` returned a non-null instance on this call or a previous call, otherwise throws `NullPointerException` if this call or a previous call to `newInstance(Object, LogNode)` returned null. Exceptions SingletonMap:E: If `newInstance(Object, LogNode)` threw an exception. InterruptedException: if the thread was interrupted while waiting for the singleton to be instantiated by another thread. NullSingletonException: if `newInstance(Object, LogNode)` returned null. NewInstanceException: if `newInstance(Object, LogNode)` threw an exception.

public V get(final K key, final LogNode log) throws SingletonMap:E, InterruptedException, NullSingletonException, NewInstanceException

Parameters

key:K: The key for the singleton.
log:LogNode: The log.

Returns:V

Exceptions

SingletonMap:E:: If newInstance(Object, LogNode) threw an exception.
InterruptedException:: if the thread was interrupted while waiting for the singleton to be instantiated by another thread.
NullSingletonException:: if newInstance(Object, LogNode) returned null.
NewInstanceException:: if newInstance(Object, LogNode) threw an exception.

isEmpty	back to summary
public boolean isEmpty() Returns true if the map is empty. Returns:boolean true, if the map is empty

isEmpty

back to summary

public boolean isEmpty()

Returns true if the map is empty.

Returns:boolean: true, if the map is empty

newInstance	back to summary
public abstract V newInstance(K key, LogNode log) throws SingletonMap:E, InterruptedException Construct a new singleton instance. Parameters key:K The key for the singleton. log:LogNode The log. Returns:V The singleton instance. This method must either return a non-null value, or throw an exception of type E. Exceptions SingletonMap:E: If something goes wrong while instantiating the new object instance. InterruptedException: if the thread was interrupted while instantiating the singleton.

newInstance

back to summary

public abstract V newInstance(K key, LogNode log) throws SingletonMap:E, InterruptedException

Construct a new singleton instance.

Parameters

key:K: The key for the singleton.
log:LogNode: The log.

Returns:V

The singleton instance. This method must either return a non-null value, or throw an exception of type E.

Exceptions

SingletonMap:E:: If something goes wrong while instantiating the new object instance.
InterruptedException:: if the thread was interrupted while instantiating the singleton.

remove	back to summary
public V remove(final K key) throws InterruptedException Remove the singleton for a given key. Parameters key:K the key Returns:V the old singleton from the map, if one was present, otherwise null. Annotations @SuppressWarnings:null Exceptions InterruptedException: if interrupted.

remove

back to summary

public V remove(final K key) throws InterruptedException

Remove the singleton for a given key.

Parameters

key:K: the key

Returns:V

the old singleton from the map, if one was present, otherwise null.

Annotations

@SuppressWarnings:null

Exceptions

InterruptedException:: if interrupted.

values	back to summary
public List<V> values() throws InterruptedException Get all valid singleton values in the map. Returns:List<V> the singleton values in the map, skipping over any value for which newInstance() threw an exception or returned null. Exceptions InterruptedException: If getting the values was interrupted.

values

back to summary

public List<V> values() throws InterruptedException

Get all valid singleton values in the map.

Returns:List<V>

the singleton values in the map, skipping over any value for which newInstance() threw an exception or returned null.

Exceptions

InterruptedException:: If getting the values was interrupted.

nonapi.io.github.classgraph.concurrency back to summary

public Class SingletonMap.NewInstanceException

Class Inheritance

extends Exception

java.lang.Object
java.lang.Throwable
java.lang.Exception
nonapi.io.github.classgraph.concurrency.SingletonMap.NewInstanceException

Thrown when SingletonMap#newInstance(Object, LogNode) throws an exception.

Field Summary

Modifier and Type	Field and Description
pack-priv static final long	serialVersionUID Hides java.lang.Exception.serialVersionUID. serialVersionUID.

Constructor Summary

Access	Constructor and Description
public < the key type K>	NewInstanceException(final K the key key, final Throwable the Throwable that was thrown t) Constructor.

Field Detail

serialVersionUID	back to summary
pack-priv static final long serialVersionUID Hides java.lang.Exception.serialVersionUID. serialVersionUID.

serialVersionUID

back to summary

pack-priv static final long serialVersionUID

Hides java.lang.Exception.serialVersionUID.

serialVersionUID.

Constructor Detail

NewInstanceException	back to summary
public <K> NewInstanceException(final K key, final Throwable t) Constructor. Parameters <K> the key type key:K the key t:Throwable the Throwable that was thrown

NewInstanceException

back to summary

public <K> NewInstanceException(final K key, final Throwable t)

Constructor.

Parameters

<K>: the key type
key:K: the key
t:Throwable: the Throwable that was thrown

nonapi.io.github.classgraph.concurrency back to summary

public Interface SingletonMap.NewInstanceFactory<V, E extends Exception>

Annotations

@FunctionalInterface

Type Parameters

<V>: The instance type.

Create a new instance.

Method Summary

Modifier and Type	Method and Description
public V	Returns: The new instance. newInstance() Create a new instance.

Method Detail

newInstance	back to summary
public V newInstance() throws SingletonMap:E, InterruptedException Create a new instance. Returns:V The new instance.

newInstance

back to summary

public V newInstance() throws SingletonMap:E, InterruptedException

Create a new instance.

Returns:V: The new instance.

nonapi.io.github.classgraph.concurrency back to summary

public Class SingletonMap.NullSingletonException

Class Inheritance

extends Exception

java.lang.Object
java.lang.Throwable
java.lang.Exception
nonapi.io.github.classgraph.concurrency.SingletonMap.NullSingletonException

Thrown when SingletonMap#newInstance(Object, LogNode) returns null.

Field Summary

Modifier and Type	Field and Description
pack-priv static final long	serialVersionUID Hides java.lang.Exception.serialVersionUID. serialVersionUID.

Constructor Summary

Access	Constructor and Description
public < the key type K>	NullSingletonException(final K the key key) Constructor.

Field Detail

serialVersionUID	back to summary
pack-priv static final long serialVersionUID Hides java.lang.Exception.serialVersionUID. serialVersionUID.

serialVersionUID

back to summary

pack-priv static final long serialVersionUID

Hides java.lang.Exception.serialVersionUID.

serialVersionUID.

Constructor Detail

NullSingletonException	back to summary
public <K> NullSingletonException(final K key) Constructor. Parameters <K> the key type key:K the key

NullSingletonException

back to summary

public <K> NullSingletonException(final K key)

Constructor.

Parameters

<K>: the key type
key:K: the key

nonapi.io.github.classgraph.concurrency back to summary

private Class SingletonMap.SingletonHolder<V>

Class Inheritance

extends Object

java.lang.Object
nonapi.io.github.classgraph.concurrency.SingletonMap.SingletonHolder

Type Parameters

<V>: the singleton type

Wrapper to allow an object instance to be put into a ConcurrentHashMap using putIfAbsent() without requiring the instance to be initialized first, so that putIfAbsent can be performed without wrapping it with a synchronized lock, and so that initialization work is not wasted if an object is already in the map for the key.

Field Summary

Modifier and Type	Field and Description
private final CountDownLatch	initialized Whether or not the singleton has been initialized (the count will have reached 0 if so).
private volatile V	singleton The singleton.

Constructor Summary

Access	Constructor and Description
private	SingletonHolder()

Method Summary

Modifier and Type	Method and Description
pack-priv V	Returns: the singleton value. get() Get the singleton value.
pack-priv void	set(final V the singleton singleton) Set the singleton value, and decreases the countdown latch to 0.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

initialized	back to summary
private final CountDownLatch initialized Whether or not the singleton has been initialized (the count will have reached 0 if so).

singleton	back to summary
private volatile V singleton The singleton. Annotations @SuppressWarnings:null

Constructor Detail

SingletonHolder	back to summary
private SingletonHolder()

Method Detail

get	back to summary
pack-priv V get() throws InterruptedException Get the singleton value. Returns:V the singleton value. Exceptions InterruptedException: if the thread was interrupted while waiting for the value to be set.

get

back to summary

pack-priv V get() throws InterruptedException

Get the singleton value.

Returns:V

the singleton value.

Exceptions

InterruptedException:: if the thread was interrupted while waiting for the value to be set.

set	back to summary
pack-priv void set(final V singleton) throws IllegalArgumentException Set the singleton value, and decreases the countdown latch to 0. Parameters singleton:V the singleton Exceptions IllegalArgumentException: if this method is called more than once (indicating an internal inconsistency).

set

back to summary

pack-priv void set(final V singleton) throws IllegalArgumentException

Set the singleton value, and decreases the countdown latch to 0.

Parameters

singleton:V: the singleton

Exceptions

IllegalArgumentException:: if this method is called more than once (indicating an internal inconsistency).

public abstract Class SingletonMap<K, V, E extends Exception>

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

public Class SingletonMap.NewInstanceException

Field Summary

Constructor Summary

Field Detail

Constructor Detail

public Interface SingletonMap.NewInstanceFactory<V, E extends Exception>

Method Summary

Method Detail

public Class SingletonMap.NullSingletonException

Field Summary

Constructor Summary

Field Detail

Constructor Detail

private Class SingletonMap.SingletonHolder<V>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail