org.apache.flink.statefun.sdk.state

Class PersistedAppendingBuffer<E>

java.lang.Object

org.apache.flink.statefun.sdk.state.PersistedAppendingBuffer<E>

Type Parameters:

E - type of the buffer elements.

public final class PersistedAppendingBuffer<E>
extends java.lang.Object

A PersistedAppendingBuffer is an append-only buffer registered within StatefulFunctions and is persisted and maintained by the system for fault-tolerance. Persisted elements in the buffer may only be updated with bulk replacements.

Created persisted buffers must be registered by using the Persisted annotation. Please see the class-level Javadoc of StatefulFunction for an example on how to do that.

See Also:

StatefulFunction

Method Summary

Modifier and Type	Method and Description
void	append(E element) Appends an element to the persisted buffer.
void	appendAll(java.util.List<E> elements) Adds all elements of a list to the persisted buffer.
void	clear() Clears all elements in the persisted buffer.
java.lang.Class<E>	elementType() Returns the type of the persisted buffer elements.
Expiration	expiration()
java.lang.String	name() Returns the unique name of the persisted buffer.
static <E> PersistedAppendingBuffer<E>	of(java.lang.String name, java.lang.Class<E> elementType) Creates a PersistedAppendingBuffer instance that may be used to access persisted state managed by the system.
static <E> PersistedAppendingBuffer<E>	of(java.lang.String name, java.lang.Class<E> elementType, Expiration expiration) Creates a PersistedAppendingBuffer instance that may be used to access persisted state managed by the system.
void	replaceWith(java.util.List<E> elements) Replace the elements in the persisted buffer with the provided list of elements.
java.lang.String	toString()
java.lang.Iterable<E>	view() Gets an unmodifiable view of the elements of the persisted buffer, as an Iterable.

Methods inherited from class java.lang.Object

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

Method Detail

of

public static <E> PersistedAppendingBuffer<E> of(java.lang.String name,
                                                 java.lang.Class<E> elementType)

Creates a PersistedAppendingBuffer instance that may be used to access persisted state managed by the system. Access to the persisted buffer is identified by an unique name and type of the elements. These may not change across multiple executions of the application.

Type Parameters:

E - the type of the elements.

Parameters:

name - the unique name of the persisted buffer state

elementType - the type of the elements of this PersistedAppendingBuffer.

Returns:

a PersistedAppendingBuffer instance.

of

public static <E> PersistedAppendingBuffer<E> of(java.lang.String name,
                                                 java.lang.Class<E> elementType,
                                                 Expiration expiration)

Creates a PersistedAppendingBuffer instance that may be used to access persisted state managed by the system. Access to the persisted buffer is identified by an unique name and type of the elements. These may not change across multiple executions of the application.

Type Parameters:

E - the type of the elements.

Parameters:

name - the unique name of the persisted buffer state

elementType - the type of the elements of this PersistedAppendingBuffer.

expiration - state expiration configuration.

Returns:

a PersistedAppendingBuffer instance.

name

public java.lang.String name()

Returns the unique name of the persisted buffer.

Returns:

unique name of the persisted buffer.

elementType

public java.lang.Class<E> elementType()

Returns the type of the persisted buffer elements.

Returns:

the type of the persisted buffer elements.

expiration

public Expiration expiration()

append

public void append(@Nonnull
                   E element)

Appends an element to the persisted buffer.

Parameters:

element - the element to add to the persisted buffer.

appendAll

public void appendAll(@Nonnull
                      java.util.List<E> elements)

Adds all elements of a list to the persisted buffer.

If an empty list is passed in, then this method has no effect and the persisted buffer remains the same.

Parameters:

elements - a list of elements to add to the persisted buffer.

replaceWith

public void replaceWith(@Nonnull
                        java.util.List<E> elements)

Replace the elements in the persisted buffer with the provided list of elements.

If an empty list is passed in, this method will have the same effect as clear().

Parameters:

elements - list of elements to replace the elements in the persisted buffer with.

view

@Nonnull
public java.lang.Iterable<E> view()

Gets an unmodifiable view of the elements of the persisted buffer, as an Iterable.

Returns:

an unmodifiable view, as an Iterable, of the elements of the persisted buffer.

clear

public void clear()

Clears all elements in the persisted buffer.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object