ch.gbrain.gwtstorage.manager

Class StorageManager

java.lang.Object

ch.gbrain.gwtstorage.manager.StorageManager

public class StorageManager
extends Object

This class deals about writing and reading objects from Type StorageItem and as well loading application resource files (eg. video files) from the applications home base (server base). This is useful when running the App in the Web but as well in a Phonegap container as we could store the files locally (cache) when running in the phonegap container.

Constructor Summary

Constructors

Constructor and Description
StorageManager() Default constructor setting up the StorageManager all inclusive Logger and Phonegap references are setup locally
StorageManager(com.googlecode.gwtphonegap.client.PhoneGap phonegap, Logger logger) Constructor allowing to inject the Phonegap reference and a Logger

Method Summary

Methods

Modifier and Type	Method and Description
void	addResourceToCache(String relativeUrl, Integer version) Check first if the resource with the given url and version is already present, if not try to download the same in a sequential way asynchronously
Boolean	checkResourceVersion(StorageResource resource) Check if the version registered in the cache does match this resources version
void	clearResourceItems() Remove all ResourceItem related keys from the LocalStorage and as well related resource files, ClearCache
void	clearStorage() Clear all cached items - key/value pairs in the LocalStorage - Related files in the cache directory
void	clearStorageItems() Remove all StorageItem related keys from the LocalStorage, thus clear the cached json objects and references etc.
int	getAllCachedResourceItems(com.google.gwt.core.client.Callback<StorageInfo,com.googlecode.gwtphonegap.client.file.FileError> callback) Retrieve all ResourceItems related keys from the LocalStorage
String	getCacheDirectory()
boolean	getCacheEnabled()
com.google.gwt.storage.client.Storage	getLocalStorage() Retrieve a reference to the local Storage (Browsers HTML5 key-value store)
String	getRemoteAppBaseUrl()
String	getRemoteResourceUrl(String relativeUrl) Retrieve the url of the resource on the remote server based on the current runtime environement
String	getStorageUrl()
boolean	getWlanEnabled()
boolean	isResourceCachingPossible() Evaluates if Caching is possible at all on the given client device at the moment of evaluation.
boolean	readStorageItem(StorageItem item, boolean useCache, int expectedVersion, int validTime, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Retrieve the item from the storage.
boolean	readStorageItemFromLocalApplication(StorageItem item, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Read the item asynch from the applications own source server with the given credentials and base path eg.
boolean	readStorageItemFromLocalFile(StorageItem item, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Read the item from the Local File storage
boolean	readStorageItemFromLocalStorage(StorageItem item) Read the item from the local html5 storage.
boolean	readStorageItemFromRemoteApplication(StorageItem item, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Read the item asynch from the configured remote application base
boolean	readStorageItemFromUrl(String url, StorageItem item, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Read the JSON item asynch from the given url and the standard name of the item eg.
boolean	retrieveResourceUrl(String relativeUrl, Integer version, com.google.gwt.core.client.Callback<String,com.googlecode.gwtphonegap.client.file.FileError> callback) Evaluates in case of the runtime (browser/phonegap) the full url where a resource must be retrieved from.
void	setCacheDirectory(String cacheDirectory)
void	setCacheEnabled(boolean cacheEnabled)
void	setRemoteAppBaseUrl(String baseUrl)
void	setStorageUrl(String storageUrl)
void	setWlanEnabled(boolean wlanEnabled)
boolean	writeStorageItemToLocalFile(StorageItem item, com.google.gwt.core.client.Callback<StorageItem,StorageError> callback) Write the item to a local file
boolean	writeStorageItemToLocalStorage(StorageItem item) Write the given item to the local HTML5 storage.

Methods inherited from class java.lang.Object

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

Constructor Detail

StorageManager

public StorageManager()

Default constructor setting up the StorageManager all inclusive Logger and Phonegap references are setup locally

StorageManager

public StorageManager(com.googlecode.gwtphonegap.client.PhoneGap phonegap,
              Logger logger)

Constructor allowing to inject the Phonegap reference and a Logger

Parameters:

phonegap - Give the phonegap reference you have already. Give null if you want it to be treated here automatically.

logger - Give a logger reference or null if you want it to be treated here locally.

Method Detail

getRemoteAppBaseUrl

public String getRemoteAppBaseUrl()

setRemoteAppBaseUrl

public void setRemoteAppBaseUrl(String baseUrl)

getStorageUrl

public String getStorageUrl()

setStorageUrl

public void setStorageUrl(String storageUrl)

getCacheDirectory

public String getCacheDirectory()

setCacheDirectory

public void setCacheDirectory(String cacheDirectory)

setCacheEnabled

public void setCacheEnabled(boolean cacheEnabled)

getCacheEnabled

public boolean getCacheEnabled()

setWlanEnabled

public void setWlanEnabled(boolean wlanEnabled)

getWlanEnabled

public boolean getWlanEnabled()

isResourceCachingPossible

public boolean isResourceCachingPossible()

Evaluates if Caching is possible at all on the given client device at the moment of evaluation.

Returns:

True if we have access to the local file system and therefore are able to provide a local resource caching.

getLocalStorage

public com.google.gwt.storage.client.Storage getLocalStorage()

Retrieve a reference to the local Storage (Browsers HTML5 key-value store)

Returns:

The local storage or null if not supported

writeStorageItemToLocalStorage

public boolean writeStorageItemToLocalStorage(StorageItem item)

Write the given item to the local HTML5 storage.

Parameters:

item - The object to be serialized and stored under the ID within the local storage

Returns:

true if the write operation succeeded

readStorageItemFromLocalStorage

public boolean readStorageItemFromLocalStorage(StorageItem item)

Read the item from the local html5 storage.

Parameters:

item - The item to be read from the local storage with the given ID as key.

Returns:

false if the read operation failed or nothing is found.

clearStorageItems

public void clearStorageItems()

Remove all StorageItem related keys from the LocalStorage, thus clear the cached json objects and references etc.

writeStorageItemToLocalFile

public boolean writeStorageItemToLocalFile(StorageItem item,
                                  com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Write the item to a local file

Parameters:

item - The StorageItem to be stored to the file system within the defined cache directory

callback - Is called once the asynch action completed or failed.

Returns:

false if the asynchronous action invocation failed.

readStorageItemFromLocalFile

public boolean readStorageItemFromLocalFile(StorageItem item,
                                   com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Read the item from the Local File storage

Parameters:

item - The StorageItem (or inherited objects) to be read from the local cache file system location.

callback - Is called once the asynch action completed or failed

Returns:

false if the asynchronous action invocation failed.

readStorageItem

public boolean readStorageItem(StorageItem item,
                      boolean useCache,
                      int expectedVersion,
                      int validTime,
                      com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Retrieve the item from the storage. First try local storage, if the version and the validTime are valid, it is returned. Else it tries to retrieve it from the remote backend. If found, it is cached locally for fast access.

Parameters:

item - The item to be read by ID from 1. the cache, 2. localAppPath 3. remoteAppPath in this priority order

useCache - If true, the system will first try to retrieve the value from the local cache before it reads the same from the applications path

validTime - The maximum age in seconds of the cache to be accepted as a valid item value, if elapsed it will try to read from the applications path / If <= 0 don't care

expectedVersion - The versionNumber which must be available in the cache to be a valid cache item. If <=0 don't care.

readStorageItemFromLocalApplication

public boolean readStorageItemFromLocalApplication(StorageItem item,
                                          com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Read the item asynch from the applications own source server with the given credentials and base path eg. /storage/v1/ch.gbrain.testapp.model.items-1.json Note: We just give the local relative url which means: - If running as local application (eg. started locally in Browser) it will load from local base - If running as web application it will load from the servers base - If running as Phonegap app it will load from the local installed base

Parameters:

item -

callback - is called once the asynch action completed or failed

Returns:

false if the asynchronous action invocation failed.

readStorageItemFromRemoteApplication

public boolean readStorageItemFromRemoteApplication(StorageItem item,
                                           com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Read the item asynch from the configured remote application base

Parameters:

item -

callback - is called once the asynch action completed or failed

Returns:

false if the asynchronous action invocation failed.

readStorageItemFromUrl

public boolean readStorageItemFromUrl(String url,
                             StorageItem item,
                             com.google.gwt.core.client.Callback<StorageItem,StorageError> callback)

Read the JSON item asynch from the given url and the standard name of the item eg. ch.gbrain.testapp.model.items-1.json

Parameters:

url - The url to read from eg. for local application relative path "storage/v1/" eg. for remote location "http://host.domain.ch/testapp/storage/v1/"

item -

callback - is called once the asynch action completed or failed

Returns:

false if the asynchronous action invocation failed.

getRemoteResourceUrl

public String getRemoteResourceUrl(String relativeUrl)

Retrieve the url of the resource on the remote server based on the current runtime environement

Parameters:

relativeUrl - relative url of the resource according the app base

Returns:

The url pointing to the resource dependent on if it is running in Phonegap container or Webbrowser

retrieveResourceUrl

public boolean retrieveResourceUrl(String relativeUrl,
                          Integer version,
                          com.google.gwt.core.client.Callback<String,com.googlecode.gwtphonegap.client.file.FileError> callback)

Evaluates in case of the runtime (browser/phonegap) the full url where a resource must be retrieved from. In case of Phonegap, it will check if we have the resource already locally stored in the cache and return a url pointing to this one instead.

Parameters:

relativeUrl - of the resource as it is available in the application itself.

version - Check if the version of the stored resource equals. Not checked if version=0

Returns:

The full url where the resource must be retrieved from (either points to the home server of the application as configured or it points to the found local cached resource file.

checkResourceVersion

public Boolean checkResourceVersion(StorageResource resource)

Check if the version registered in the cache does match this resources version

Returns:

true if the version matches the cache, false if not. If there was no cache yet, returns null

clearResourceItems

public void clearResourceItems()

Remove all ResourceItem related keys from the LocalStorage and as well related resource files, ClearCache

addResourceToCache

public void addResourceToCache(String relativeUrl,
                      Integer version)

Check first if the resource with the given url and version is already present, if not try to download the same in a sequential way asynchronously

Parameters:

relativeUrl -

version -

clearStorage

public void clearStorage()

Clear all cached items - key/value pairs in the LocalStorage - Related files in the cache directory

getAllCachedResourceItems

public int getAllCachedResourceItems(com.google.gwt.core.client.Callback<StorageInfo,com.googlecode.gwtphonegap.client.file.FileError> callback)

Retrieve all ResourceItems related keys from the LocalStorage

Returns:

The number of resources which will be evaluated and for which callbacks have to be expected