Storage (GWT Javadoc)

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## com.google.gwt.storage.client
Class Storage

    java.lang.Object
      com.google.gwt.storage.client.Storage

    public final class Storage

extends java.lang.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
`(package private) static StorageImpl` | `impl`

Method Summary
`static HandlerRegistration` | `addStorageEventHandler(StorageEvent.Handler handler)` Registers an event handler for StorageEvents.
`void` | `clear()` Removes all items in the Storage.
`java.lang.String` | `getItem(java.lang.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.
`java.lang.String` | `key(int index)` Returns the key at the specified index.
`void` | `removeItem(java.lang.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(java.lang.String key, java.lang.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 Detail

### impl

    static final StorageImpl impl

Method Detail

### 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 java.lang.String getItem(java.lang.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 java.lang.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(java.lang.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(java.lang.String key,
                        java.lang.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)

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