org.eclipse.rap.rwt.service
Interface SettingStore

All Superinterfaces:

ISettingStore

All Known Implementing Classes:

FileSettingStore

public interface SettingStore
extends ISettingStore

A setting store is a persistent store for user-specific settings (i.e. key/value pairs). The data in this store is kept beyond the scope of a single session.

A setting store instance is always associated with the current user session. Any settings being put into the store (via setAttribute(String, String)) are considered persisted from that point on.

To retrieve data stored in a previous session, a client can invoke the method loadById(String) with the ID of the session to load into the store. This will load any data stored under that id into the current setting store.

The framework will assign a new setting store to each new UI session, based on the current session id. After the user has authenticated, application developers can use the loadById(String) method to initialize the store with persisted data stored under that id during a previous session. Obviously, any data that is set into the store from that point on, will also be persisted under the current id and will also be available in the future.

Custom setting store implementations are supported, those must provide a corresponding SettingStoreFactory.

Since:

2.0

See Also:

FileSettingStore

Method Summary

void	addSettingStoreListener(SettingStoreListener listener) Attaches the given listener to this setting store.
java.lang.String	getAttribute(java.lang.String name) Returns the attribute stored under the specified name in this setting store.
java.util.Enumeration<java.lang.String>	getAttributeNames() Returns an Enumeration of strings with the names of all attributes in this setting store.
java.lang.String	getId() Returns the unique identifier of this setting store.
void	loadById(java.lang.String id) Replaces the contents of this setting store with the persisted contents associated with the given ID.
void	removeAttribute(java.lang.String name) Removes the attribute stored under the specified name from this setting store.
void	removeSettingStoreListener(SettingStoreListener listener) Removes the given listener from this setting store.
void	setAttribute(java.lang.String name, java.lang.String value) Stores a given attribute in this setting store, using the name specified.

Method Detail

getAttribute

java.lang.String getAttribute(java.lang.String name)

Returns the attribute stored under the specified name in this setting store.

Specified by:

getAttribute in interface ISettingStore

Parameters:

name - a non-null String specifying the name of the attribute

Returns:

the attribute stored under the given name or null if no attribute is stored under that name

getAttributeNames

java.util.Enumeration<java.lang.String> getAttributeNames()

Returns an Enumeration of strings with the names of all attributes in this setting store.

Specified by:

getAttributeNames in interface ISettingStore

Returns:

an enumeration with the attribute names in this setting store, never null

setAttribute

void setAttribute(java.lang.String name,
                  java.lang.String value)
                  throws java.io.IOException

Stores a given attribute in this setting store, using the name specified. If an attribute with the same name is already stored in this setting store, the previous value is replaced. The attribute is considered persisted when after this method completes.

If the value is null, this has the same effect as calling removeAttribute(String).

SettingStoreListeners attached to this instance will be notified after an attribute has been stored.

Specified by:

setAttribute in interface ISettingStore

Parameters:

name - the name of the attribute, must not be null or empty

value - the attribute to store, may be null

Throws:

java.io.IOException - if the load operation failed to complete normally

removeAttribute

void removeAttribute(java.lang.String name)
                     throws java.io.IOException

Removes the attribute stored under the specified name from this setting store. If no attribute is stored under the specified name, this method does nothing.

SettingStoreListeners attached to this instance will be notified after an attribute has been removed.

Specified by:

removeAttribute in interface ISettingStore

Parameters:

name - the name of the attribute to remove, must not be null

Throws:

java.io.IOException - if the remove operation failed to complete normally

loadById

void loadById(java.lang.String id)
              throws java.io.IOException

Replaces the contents of this setting store with the persisted contents associated with the given ID.

The attributes of this setting store will remain associated with the old id, but will be removed from this store instance. SettingStoreListeners attached to this store will receive a notification for each removed attribute.

During the load operation this store will be filled with the attributes associated with the new ID. SettingStoreListeners attached to this store will receive a notification for each added attribute.

After the load operation this store will only hold attributes associated with the new id value.

Specified by:

loadById in interface ISettingStore

Parameters:

id - the ID of the settings to load, must not be null or empty

Throws:

java.io.IOException - if the load operation failed to complete normally

java.lang.IllegalArgumentException - if the given id is empty

getId

java.lang.String getId()

Returns the unique identifier of this setting store.

Specified by:

getId in interface ISettingStore

Returns:

a non-empty string, never null

addSettingStoreListener

void addSettingStoreListener(SettingStoreListener listener)

Attaches the given listener to this setting store. Listeners will be notified of changes in the store. If the listener has already been added to this store, this method does nothing.

Specified by:

addSettingStoreListener in interface ISettingStore

Parameters:

listener - the listener to add, must not be null

removeSettingStoreListener

void removeSettingStoreListener(SettingStoreListener listener)

Removes the given listener from this setting store. If the listener has not been added, this method does nothing.

Specified by:

removeSettingStoreListener in interface ISettingStore

Parameters:

listener - the listener to remove, must not be null