com.spotify.helios.servicescommon

Class PersistentAtomicReference<T>

java.lang.Object

com.spotify.helios.servicescommon.PersistentAtomicReference<T>

public class PersistentAtomicReference<T>
extends Object

A class that is similar to AtomicReference but is backed by a file, so can be persisted across a server restart. Assumes the underlying type can be serialized by Jackson.

Strangely, this is not actually atomic in the AtomicReference way; i.e. not threadsafe, nor does it do CAS.

Method Summary

Modifier and Type	Method and Description
static <T> PersistentAtomicReference<T>	create(Path filename, com.fasterxml.jackson.databind.JavaType javaType, com.google.common.base.Supplier<? extends T> initialValue)
static <T> PersistentAtomicReference<T>	create(Path filename, com.fasterxml.jackson.core.type.TypeReference<T> typeReference, com.google.common.base.Supplier<? extends T> initialValue)
static <T> PersistentAtomicReference<T>	create(String filename, com.fasterxml.jackson.databind.JavaType javaType, com.google.common.base.Supplier<? extends T> initialValue)
static <T> PersistentAtomicReference<T>	create(String filename, com.fasterxml.jackson.core.type.TypeReference<T> typeReference, com.google.common.base.Supplier<? extends T> initialValue)
T	get() Returns the value stored.
void	set(T newValue) Set the reference to newValue.
void	setUnchecked(T newValue) Set the reference to newValue, and wraps IOExceptions in RuntimeExceptions.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

set

public void set(T newValue)
         throws IOException,
                InterruptedException

Set the reference to newValue.

Parameters:

newValue - The value to set.

Throws:

IOException - If an error occurs working with the file on disk.

InterruptedException - If the thread is interrupted.

setUnchecked

public void setUnchecked(T newValue)
                  throws InterruptedException

Set the reference to newValue, and wraps IOExceptions in RuntimeExceptions.

Parameters:

newValue - The value to set.

Throws:

InterruptedException - If the thread is interrupted.

get

public T get()

Returns the value stored.

Returns:

The value.

create

public static <T> PersistentAtomicReference<T> create(Path filename,
                                                      com.fasterxml.jackson.core.type.TypeReference<T> typeReference,
                                                      com.google.common.base.Supplier<? extends T> initialValue)
                                               throws IOException,
                                                      InterruptedException

Throws:

IOException

InterruptedException

create

public static <T> PersistentAtomicReference<T> create(String filename,
                                                      com.fasterxml.jackson.core.type.TypeReference<T> typeReference,
                                                      com.google.common.base.Supplier<? extends T> initialValue)
                                               throws IOException,
                                                      InterruptedException

Throws:

IOException

InterruptedException

create

public static <T> PersistentAtomicReference<T> create(Path filename,
                                                      com.fasterxml.jackson.databind.JavaType javaType,
                                                      com.google.common.base.Supplier<? extends T> initialValue)
                                               throws IOException,
                                                      InterruptedException

Throws:

IOException

InterruptedException

create

public static <T> PersistentAtomicReference<T> create(String filename,
                                                      com.fasterxml.jackson.databind.JavaType javaType,
                                                      com.google.common.base.Supplier<? extends T> initialValue)
                                               throws IOException,
                                                      InterruptedException

Throws:

IOException

InterruptedException

toString

public String toString()

Overrides:

toString in class Object