org.ocap.storage.StorageManager Maven / Gradle / Ivy
package org.ocap.storage;
import org.ocap.storage.StorageProxy;
import org.ocap.storage.StorageManagerListener;
/**
* This class represents the storage manager which keeps track of the storage
* devices attached to the system.
**/
public abstract class StorageManager
{
/**
* Protected default constructor.
**/
protected StorageManager()
{
}
/**
* Gets the singleton instance of the storage manager. The singleton MAY be
* implemented using application or implementation scope.
*
* @return The storage manager.
**/
public static StorageManager getInstance()
{
return null;
}
/**
* Gets the set of {@link StorageProxy} instances representing all
* of the currently attached or embedded storage devices.
*
* @return An array of StorageProxy objects. If no application
* accessible storage proxies are available, returns a 0 length array.
**/
public abstract StorageProxy [] getStorageProxies();
/**
* Adds a listener to receive StorageManagerEvents when a storage proxy
* is added, removed or changes state.
*
* @param listener The storage manager listener to be added.
*
* @throws IllegalArgumentException if the listener parameter is null.
**/
public abstract void addStorageManagerListener(StorageManagerListener listener);
/**
* Removes a listener so that it no longer receives
* StorageManagerEvents when storage proxies change.
* This method has no effect if the given listener had not been added.
*
* @param listener The storage manager listener to be removed.
*
* @throws IllegalArgumentException if the listener parameter is null.
**/
public abstract void removeStorageManagerListener(StorageManagerListener listener);
/**
* Gets the total amount of persistent storage under the location
* indicated by the dvb.persistent.root property and that is usable
* by all OCAP-J applications. This value SHALL remain constant.
*
* @return Amount of total persistent storage in bytes.
*/
public abstract long getTotalPersistentStorage();
/**
* Gets the available amount of persistent storage under the location
* indicated by the dvb.persistent.root property that is available to
* all OCAP-J applications. The value returned by this method can be
* incorrect as soon as this method returns and SHOULD be interpreted by
* applications as an approximation.
*
* @return Amount of available persistent storage in bytes.
*/
public abstract long getAvailablePersistentStorage();
/**
* Adds a listener for high water mark reached in available persistent
* storage indicated by the dvb.persistent.root property. This is a
* system wide indication. Listeners are informed when a percentage of
* the total persistent storage has been allocated for application use.
* Listeners are only informed when the high water mark is reached or
* exceeded.
*
* @param listener The listener to add.
* @param highWaterMark Percentage of the available persistent storage
* remaining when the listener is to be informed. For instance,
* if the total available persistent storage is 1MB and the high
* water mark is 75 then high water listeners will be informed when
* 750KB have been allocated for application use.
*
* @throws IllegalArgumentException if the listener parameter could not be
* added or is null.
*/
public abstract void addAvailableStorageListener(
AvailableStorageListener listener,
int highWaterMark);
/**
* Removes an available storage listener that was registered using the
* addAvailableStorageListener method. If the parameter
* is not currently registered this method does nothing successfully.
*
* @param listener The listener to remove.
*
* @throws IllegalArgumentException if the parameter is null.
*/
public abstract void removeAvailableStorageListener(
AvailableStorageListener listener);
}