org.eclipse.core.runtime.preferences

Class AbstractPreferenceStorage

java.lang.Object

org.eclipse.core.runtime.preferences.AbstractPreferenceStorage

public abstract class AbstractPreferenceStorage
extends java.lang.Object

Abstract class which can be used to help provide an alternate storage mechanism for Eclipse preferences. Clients can over-ride this class and implement the appropriate methods to read/persist preferences.

Since:

3.5

Constructor Summary

Constructors

Constructor and Description
AbstractPreferenceStorage()

Method Summary

Modifier and Type	Method and Description
abstract java.lang.String[]	childrenNames(java.lang.String nodePath) Return a string array containing the names of the children for the node with the given path.
abstract java.util.Properties	load(java.lang.String nodePath) Return a java.util.Properties object containing the preference key/value pairs for the preference node with the specified path, and its children.
protected java.util.Properties	loadProperties(java.io.InputStream input) Helper method to load a java.util.Properties file from the given input stream.
abstract void	removed(java.lang.String nodePath) Callback to inform the client that the preference node with the specified path has been deleted and the client should react accordingly and make the appropriate changes to the storage.
abstract void	save(java.lang.String nodePath, java.util.Properties properties) Save the given java.util.Properties object which represents preference key/value pairs for the preference node represented by the given path.
protected void	saveProperties(java.io.OutputStream output, java.util.Properties properties) Helper method to save the given java.util.Properties object to the given output stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractPreferenceStorage

public AbstractPreferenceStorage()

Method Detail

load

public abstract java.util.Properties load(java.lang.String nodePath)
                                   throws BackingStoreException

Return a java.util.Properties object containing the preference key/value pairs for the preference node with the specified path, and its children.

The table keys consist of an optional child node path and separator, followed by the property key. The table values are the values of the properties.

     [childNodePath/]propertyKey=propertyValue
 

Note: Whether they are absolute or relative, the paths in the returned Properties object are always interpreted as relative to the node specified by nodePath.

Parameters:

nodePath - the absolute path of the preference node

Returns:

a java.util.Properties object or null

Throws:

BackingStoreException - if there was a problem loading the properties

save

public abstract void save(java.lang.String nodePath,
                          java.util.Properties properties)
                   throws BackingStoreException

Save the given java.util.Properties object which represents preference key/value pairs for the preference node represented by the given path.

Clients are reminded that if the given properties object is empty then the preference node has been removed and they should react accordingly (e.g. for instance by removing the file on disk)

Parameters:

nodePath - the absolute path of the preference node

properties - the java.util.Properties object to store

Throws:

BackingStoreException - if there was a problem saving the properties

loadProperties

protected java.util.Properties loadProperties(java.io.InputStream input)
                                       throws BackingStoreException

Helper method to load a java.util.Properties file from the given input stream. The stream will be closed on completion of the operation.

Parameters:

input - the stream to load from

Returns:

the java.util.Properties object loaded from the stream

Throws:

BackingStoreException - if there was a problem loading the file

saveProperties

protected void saveProperties(java.io.OutputStream output,
                              java.util.Properties properties)
                       throws BackingStoreException

Helper method to save the given java.util.Properties object to the given output stream. The stream will be closed at the end of the operation.

Parameters:

output - the stream to store the object to

properties - the object to store

Throws:

BackingStoreException - if there was a problem saving the object

childrenNames

public abstract java.lang.String[] childrenNames(java.lang.String nodePath)
                                          throws BackingStoreException

Return a string array containing the names of the children for the node with the given path. If there are no children then an empty array is returned. One example where this method is commonly called, is at the scope root when discovering the initial children.

Parameters:

nodePath - the path for the preference node

Returns:

the array of children names

Throws:

BackingStoreException - if there was a problem retrieving the child names

removed

public abstract void removed(java.lang.String nodePath)

Callback to inform the client that the preference node with the specified path has been deleted and the client should react accordingly and make the appropriate changes to the storage. (e.g. delete the file/information associated with that node)

Parameters:

nodePath - the absolute path of the preference node