Package com.google.gwt.storage.client

Class Storage

java.lang.Object

com.google.gwt.storage.client.Storage

public final class Storage
extends Object

Implements the HTML5 Storage interface.

You can obtain a Storage by either invoking getLocalStorageIfSupported() or getSessionStorageIfSupported().

Experimental API: This API is still under development and is subject to change.

If Web Storage is NOT supported in the browser, these methods return null.

Note: Storage events into other windows are not supported.

This may not be supported on all browsers.

See Also:

• W3C Web Storage - Storage
• Safari Client-Side Storage and Offline Applications Programming Guide - Key-Value Storage
• Quirksmode.org - HTML5 Compatibility - Storage
• Wiki - Quickstart Guide

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final StorageImpl	impl

Method Summary

Modifier and Type	Method	Description
static HandlerRegistration	addStorageEventHandler(StorageEvent.Handler handler)	Registers an event handler for StorageEvents.
void	clear()	Removes all items in the Storage.
String	getItem(String key)	Returns the item in the Storage associated with the specified key.
int	getLength()	Returns the number of items in this Storage.
static Storage	getLocalStorageIfSupported()	Returns a Local Storage.
static Storage	getSessionStorageIfSupported()	Returns a Session Storage.
static boolean	isLocalStorageSupported()	Returns true if the localStorage part of the Storage API is supported on the running platform.
static boolean	isSessionStorageSupported()	Returns true if the sessionStorage part of the Storage API is supported on the running platform.
static boolean	isSupported()	Returns true if the Storage API (both localStorage and sessionStorage) is supported on the running platform.
String	key(int index)	Returns the key at the specified index.
void	removeItem(String key)	Removes the item in the Storage associated with the specified key.
static void	removeStorageEventHandler(StorageEvent.Handler handler)	De-registers an event handler for StorageEvents.
void	setItem(String key, String data)	Sets the value in the Storage associated with the specified key to the specified data.

Methods inherited from class java.lang.Object

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

Field Details

impl

static final StorageImpl impl

Method Details

addStorageEventHandler

public static HandlerRegistration addStorageEventHandler(StorageEvent.Handler handler)

Registers an event handler for StorageEvents.

Parameters:

handler -

Returns:

HandlerRegistration used to remove this handler

See Also:

• W3C Web Storage - the storage event

getLocalStorageIfSupported

public static Storage getLocalStorageIfSupported()

Returns a Local Storage.

The returned storage is associated with the origin of the Document.

Returns:

the localStorage instance, or null if Web Storage is NOT supported.

See Also:

• W3C Web Storage - localStorage

getSessionStorageIfSupported

public static Storage getSessionStorageIfSupported()

Returns a Session Storage.

The returned storage is associated with the current top-level browsing context.

Returns:

the sessionStorage instance, or null if Web Storage is NOT supported.

See Also:

• W3C Web Storage - sessionStorage

isLocalStorageSupported

public static boolean isLocalStorageSupported()

Returns true if the localStorage part of the Storage API is supported on the running platform.

isSessionStorageSupported

public static boolean isSessionStorageSupported()

Returns true if the sessionStorage part of the Storage API is supported on the running platform.

isSupported

public static boolean isSupported()

Returns true if the Storage API (both localStorage and sessionStorage) is supported on the running platform.

removeStorageEventHandler

public static void removeStorageEventHandler(StorageEvent.Handler handler)

De-registers an event handler for StorageEvents.

Parameters:

handler -

See Also:

• W3C Web Storage - the storage event

clear

public void clear()

Removes all items in the Storage.

See Also:

• W3C Web Storage - Storage.clear()

getItem

public String getItem(String key)

Returns the item in the Storage associated with the specified key.

Parameters:

key - the key to a value in the Storage

Returns:

the value associated with the given key

See Also:

• W3C Web Storage - Storage.getItem(k)

getLength

public int getLength()

Returns the number of items in this Storage.

Returns:

number of items in this Storage

See Also:

• W3C Web Storage - Storage.length()

key

public String key(int index)

Returns the key at the specified index.

Parameters:

index - the index of the key

Returns:

the key at the specified index in this Storage

See Also:

• W3C Web Storage - Storage.key(n)

removeItem

public void removeItem(String key)

Removes the item in the Storage associated with the specified key.

Parameters:

key - the key to a value in the Storage

See Also:

• W3C Web Storage - Storage.removeItem(k)

setItem

public void setItem(String key,
 String data)

Sets the value in the Storage associated with the specified key to the specified data. Note: The empty string may not be used as a key.

Parameters:

key - the key to a value in the Storage

data - the value associated with the key

See Also:

• W3C Web Storage - Storage.setItem(k,v)