org.glassfish.jersey.examples.feedcombiner.store

Interface InMemoryDataStore

All Known Subinterfaces:

ObservableDataStore

All Known Implementing Classes:

ReadWriteLockDataStore

public interface InMemoryDataStore

A simple in-memory store for serializable values based on key.

All instances of this interface and their methods are thread-safe.

Author:

Petr Bouda (petr.bouda at oracle.com)

Method Summary

Modifier and Type	Method and Description
<T extends Serializable> T	get(String key, Class<T> type) Retrieve data from the data store.
void	load(InputStream in) Load content of the data store from an input stream.
<T extends Serializable> Serializable	put(String key, T data) Store new data or replace existing data stored under a key with the new data.
void	save(OutputStream out) Save current content of the data store to an output stream.

Method Detail

put

<T extends Serializable> Serializable put(String key,
                                          T data)

Store new data or replace existing data stored under a key with the new data.

The method throws an exception if the key is null.

Parameters:

key - a unique identifier of the location where the data should be stored or replaced. Must not be null.

data - new data to be stored under the given key. May be null, in which case the data will be removed from the store.

Returns:

null if there are no data stored under the given key or any replaced data previously stored under the key.

Throws:

NullPointerException - in case the key is null.

get

<T extends Serializable> T get(String key,
                               Class<T> type)

Retrieve data from the data store.

The method retrieves the data stored under a unique key from the data store and returns the data cast into the Java type specified by type parameter.

Parameters:

key - a unique identifier of the location from which the stored data should be retrieved. Must not be null.

type - expected Java type of the data being retrieved. Must not be null.

Returns:

retrieved data or null if there are no data stored under the given key.

Throws:

NullPointerException - in case the key or type is null.

ClassCastException - in case the data stored under the given key cannot be cast to the Java type represented by type parameter.

save

void save(OutputStream out)
   throws IOException

Save current content of the data store to an output stream.

The operation is guaranteed to produce a consistent snapshot of the data store inner state.

Parameters:

out - output stream where the content of the data store is saved. The method does not close the stream.

Throws:

IOException - in case the save operation failed.

load

void load(InputStream in)
   throws IOException

Load content of the data store from an input stream.

Any content previously stored in the data store will be discarded and replaced with the content loaded from the input stream.

Parameters:

in - input stream from which the content of the data store is loaded. The method does not close the stream.

Throws:

IOException - in case the load operation failed.