org.openide.loaders

Class DataObject

java.lang.Object

org.openide.loaders.DataObject

All Implemented Interfaces:

Serializable, Node.Cookie, HelpCtx.Provider, Lookup.Provider

Direct Known Subclasses:

MultiDataObject

public abstract class DataObject
extends Object
implements Node.Cookie, Serializable, HelpCtx.Provider, Lookup.Provider

Object that represents one or more file objects, with added behavior accessible though DataObject.getLookup() lookup pattern. Since version 6.0 this class implements Lookup.Provider.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	DataObject.Container Interface for objects that can contain other data objects.
static interface	DataObject.Factory Factory interface for converting file object to data objects.
static interface	DataObject.Registration Registers new file type into the system.
static interface	DataObject.Registrations May be used to allow multiple DataObject.Registration at one place.
static class	DataObject.Registry Registry of modified data objects.

Field Summary

Fields

Modifier and Type	Field and Description
static String	PROP_COOKIE Name of the property used during notification of changes in the set of cookies attached to this object.
static String	PROP_FILES Name of files property.
static String	PROP_HELP Name of the help context property.
static String	PROP_MODIFIED Name of the modified property.
static String	PROP_NAME Name of the name property.
static String	PROP_PRIMARY_FILE Name of primary file property.
static String	PROP_TEMPLATE Name of the template property.
static String	PROP_VALID Name of valid property.

Constructor Summary

Constructors

Constructor and Description
DataObject(FileObject pf, DataLoader loader) Create a new data object.

Method Summary

Modifier and Type	Method and Description
void	addPropertyChangeListener(PropertyChangeListener l) Add a property change listener.
void	addVetoableChangeListener(VetoableChangeListener l) Add a listener to vetoable changes.
DataObject	copy(DataFolder f) Copy this object to a folder.
DataObject	createFromTemplate(DataFolder f) Create a new object from template (with a name depending on the template).
DataObject	createFromTemplate(DataFolder f, String name) Create a new object from template.
DataObject	createFromTemplate(DataFolder f, String name, Map<String,? extends Object> parameters) More generic way how to instantiate a DataObject.
protected Node	createNodeDelegate() Provides node that should represent this data object.
DataShadow	createShadow(DataFolder f) Creates shadow for this object in specified folder.
void	delete() Delete this object.
protected void	dispose() Allows subclasses to discard the object.
Set<FileObject>	files() Get all contained files.
static DataObject	find(FileObject fo) Finds the data object for a specified file object.
protected void	firePropertyChange(String name, Object oldValue, Object newValue) Fires property change notification to all listeners registered via DataObject.addPropertyChangeListener(java.beans.PropertyChangeListener).
protected void	fireVetoableChange(String name, Object oldValue, Object newValue) Fires vetoable change notification.
<T extends Node.Cookie> T	getCookie(Class<T> c) Obtain a cookie from the data object.
protected <T extends Node.Cookie> T	getCookie(DataShadow shadow, Class<T> clazz) When a request for a cookie is done on a DataShadow of this DataObject this methods gets called (by default) so the DataObject knows which DataShadow is asking and extract some information from the shadow itself.
DataFolder	getFolder() Get the folder this data object is stored in.
abstract HelpCtx	getHelpCtx() Get help context for this object.
DataLoader	getLoader() Get the loader that created this data object.
Lookup	getLookup() Represents a context of the data object.
String	getName() Get the name of the data object.
Node	getNodeDelegate() Get the node delegate.
FileObject	getPrimaryFile() Get the primary file for this data object.
static DataObject.Registry	getRegistry() Get the registry containing all modified objects.
protected abstract DataObject	handleCopy(DataFolder f) Copy this object to a folder (implemented by subclasses).
protected DataObject	handleCopyRename(DataFolder f, String name, String ext) Copy and rename this object to a folder (implemented by subclasses).
protected abstract DataObject	handleCreateFromTemplate(DataFolder df, String name) Create a new data object from template (implemented in subclasses).
protected DataShadow	handleCreateShadow(DataFolder f) Creates shadow for this object in specified folder (overridable in subclasses).
protected abstract void	handleDelete() Delete this object (implemented by subclasses).
protected abstract FileObject	handleMove(DataFolder df) Move this object to another folder (implemented in subclasses).
protected abstract FileObject	handleRename(String name) Rename this object (implemented in subclasses).
abstract boolean	isCopyAllowed() Test whether the object may be copied.
abstract boolean	isDeleteAllowed() Test whether the object may be deleted.
boolean	isModified() Test whether the object is modified.
abstract boolean	isMoveAllowed() Test whether the object may be moved.
abstract boolean	isRenameAllowed() Test whether the object may be renamed.
boolean	isShadowAllowed() Test whether the object may create shadows.
boolean	isTemplate() Get the template status of this data object.
boolean	isValid() Test whether the data object is still valid and usable.
protected void	markFiles() Mark all contained files as belonging to this loader.
void	move(DataFolder df) Move this object to another folder.
void	removePropertyChangeListener(PropertyChangeListener l) Remove a property change listener.
void	removeVetoableChangeListener(VetoableChangeListener l) Add a listener to vetoable changes.
void	rename(String name) Rename this object.
void	setModified(boolean modif) Set whether the object is considered modified.
void	setTemplate(boolean newTempl) Set the template status of this data object.
void	setValid(boolean valid) Setter that allows to destroy this data object.
protected FileLock	takePrimaryFileLock() Obtains lock for primary file.
String	toString()
Object	writeReplace() The Serialization replacement for this object stores the primary file instead.

Methods inherited from class java.lang.Object

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

Field Detail

PROP_TEMPLATE

public static final String PROP_TEMPLATE

Name of the template property.

See Also:

Constant Field Values

PROP_NAME

public static final String PROP_NAME

Name of the name property.

See Also:

Constant Field Values

PROP_HELP

public static final String PROP_HELP

Name of the help context property.

See Also:

Constant Field Values

PROP_MODIFIED

public static final String PROP_MODIFIED

Name of the modified property.

See Also:

Constant Field Values

PROP_COOKIE

public static final String PROP_COOKIE

Name of the property used during notification of changes in the set of cookies attached to this object.

See Also:

Constant Field Values

PROP_VALID

public static final String PROP_VALID

Name of valid property. Allows listening to deletion or disposal of the data object.

See Also:

Constant Field Values

PROP_PRIMARY_FILE

public static final String PROP_PRIMARY_FILE

Name of primary file property. Primary file is changed when the object is moved

See Also:

Constant Field Values

PROP_FILES

public static final String PROP_FILES

Name of files property. Allows listening to set of files handled by this object.

See Also:

Constant Field Values

Constructor Detail

DataObject

public DataObject(FileObject pf,
                  DataLoader loader)
           throws DataObjectExistsException

Create a new data object.

Parameters:

pf - primary file object for this data object

loader - loader that created the data object

Throws:

DataObjectExistsException - if there is already a data object for this primary file

Method Detail

dispose

protected void dispose()

Allows subclasses to discard the object. When an object is discarded, it is released from the list of objects registered in the system. Then the contents of the parent folder (if it still exists) are rescanned, which may result in the creation of a new data object for the primary file.

The normal use of this method is to change the type of a data object. Because this would usually only be invoked from the original data object, it is protected.

setValid

public void setValid(boolean valid)
              throws PropertyVetoException

Setter that allows to destroy this data object. Because such operation can be dangerous and not always possible (if the data object is opened in editor) it can be vetoed. Either by this data object or by any vetoable listener attached to this object (like editor support)

Parameters:

valid - should be false

Throws:

PropertyVetoException - if the invalidation has been vetoed

isValid

public final boolean isValid()

Test whether the data object is still valid and usable.

The object can become invalid when it is deleted, its files are deleted, or DataObject.dispose() is called.

When the validity of the object changes a property change event is fired, so anyone can listen and be notified when the object is deleted/disposed.

getLoader

public final DataLoader getLoader()

Get the loader that created this data object.

Returns:

the data loader

markFiles

protected final void markFiles()
                        throws IOException

Mark all contained files as belonging to this loader. If the files are rescanned (e.g. after a disposal), the current data loader will be given preference.

Throws:

IOException

files

public Set<FileObject> files()

Get all contained files. These file objects should ideally have had the important flag set appropriately.

The default implementation returns a set consisting only of the primary file.

Returns:

set of files

getNodeDelegate

public final Node getNodeDelegate()

Get the node delegate. Either creates it (if it does not already exist) or returns a previously created instance of it.

Returns:

the node delegate (without parent) for this data object

See Also:

Datasystems API - Node Delegates

createNodeDelegate

protected Node createNodeDelegate()

Provides node that should represent this data object.

The default implementation creates an instance of DataNode. Most subclasses will override this method to provide a DataNode (usually subclassed).

This method is called only once per data object.

It is strongly recommended that the resulting node will, when asked for the cookie DataObject.class, return this same data object.

It is also recommended that the node:

1. Base its name on DataObject.getName().
2. Base its display name additionally on DataNode.getShowFileExtensions().
3. Tune its display name and icon according to FileSystem.Status.

Returns:

the node delegate (without parent) for this data object

See Also:

Datasystems API - Creating a node delegate

takePrimaryFileLock

protected FileLock takePrimaryFileLock()
                                throws IOException

Obtains lock for primary file.

Returns:

the lock

Throws:

IOException - if taking the lock fails

setTemplate

public final void setTemplate(boolean newTempl)
                       throws IOException

Set the template status of this data object.

Parameters:

newTempl - true if the object should be a template

Throws:

IOException - if setting the template state fails

isTemplate

public final boolean isTemplate()

Get the template status of this data object.

Returns:

true if it is a template

isDeleteAllowed

public abstract boolean isDeleteAllowed()

Test whether the object may be deleted.

Returns:

true if it may

isCopyAllowed

public abstract boolean isCopyAllowed()

Test whether the object may be copied.

Returns:

true if it may

isMoveAllowed

public abstract boolean isMoveAllowed()

Test whether the object may be moved.

Returns:

true if it may

isShadowAllowed

public boolean isShadowAllowed()

Test whether the object may create shadows.

The default implementation returns true.

Returns:

true if it may

isRenameAllowed

public abstract boolean isRenameAllowed()

Test whether the object may be renamed.

Returns:

true if it may

isModified

public boolean isModified()

Test whether the object is modified.

Returns:

true if it is modified

setModified

public void setModified(boolean modif)

Set whether the object is considered modified. Also fires a change event. If the new value is true, the data object is added into a registry of opened data objects. If the new value is false, the data object is removed from the registry.

getHelpCtx

public abstract HelpCtx getHelpCtx()

Get help context for this object.

Specified by:

getHelpCtx in interface HelpCtx.Provider

Returns:

the help context

getPrimaryFile

public final FileObject getPrimaryFile()

Get the primary file for this data object. For example, Java source uses *.java and *.class files but the primary one is always *.java. Please note that two data objects are equivalent if they use the same primary file.

Warning: do not call Node.getHandle() or DefaultHandle.createHandle(org.openide.nodes.Node) in this method.

Returns:

the primary file

find

public static DataObject find(FileObject fo)
                       throws DataObjectNotFoundException

Finds the data object for a specified file object.

Parameters:

fo - file object

Returns:

the data object for that file

Throws:

DataObjectNotFoundException - if the file does not have a data object

getRegistry

public static DataObject.Registry getRegistry()

Get the registry containing all modified objects.

Returns:

the registry

getName

public String getName()

Get the name of the data object.

The default implementation uses the name of the primary file.

Returns:

the name

toString

public String toString()

Overrides:

toString in class Object

getFolder

public final DataFolder getFolder()

Get the folder this data object is stored in.

Returns:

the folder; null if the primary file is the root of its filesystem

copy

public final DataObject copy(DataFolder f)
                      throws IOException

Copy this object to a folder. The copy of the object is required to be deletable and movable.

An event is fired, and atomicity is implemented.

Parameters:

f - the folder to copy the object to

Returns:

the new object

Throws:

IOException - if something went wrong

handleCopy

protected abstract DataObject handleCopy(DataFolder f)
                                  throws IOException

Copy this object to a folder (implemented by subclasses).

Parameters:

f - target folder

Returns:

the new data object

Throws:

IOException - if an error occures

handleCopyRename

protected DataObject handleCopyRename(DataFolder f,
                                      String name,
                                      String ext)
                               throws IOException

Copy and rename this object to a folder (implemented by subclasses).

Parameters:

f - target folder

name - new file name

ext - new file extension

Returns:

the new data object

Throws:

IOException - if an error occures or the file cannot be copied/renamed

Since:

6.3

delete

public final void delete()
                  throws IOException

Delete this object.

Events are fired and atomicity is implemented.

Throws:

IOException - if an error occures

handleDelete

protected abstract void handleDelete()
                              throws IOException

Delete this object (implemented by subclasses).

Throws:

IOException - if an error occures

rename

public final void rename(String name)
                  throws IOException

Rename this object.

Events are fired and atomicity is implemented.

Parameters:

name - the new name

Throws:

IOException - if an error occurs

handleRename

protected abstract FileObject handleRename(String name)
                                    throws IOException

Rename this object (implemented in subclasses).

Parameters:

name - name to rename the object to

Returns:

new primary file of the object

Throws:

IOException - if an error occures

move

public final void move(DataFolder df)
                throws IOException

Move this object to another folder.

An event is fired and atomicity is implemented.

Parameters:

df - folder to move object to

Throws:

IOException - if an error occurs

handleMove

protected abstract FileObject handleMove(DataFolder df)
                                  throws IOException

Move this object to another folder (implemented in subclasses).

Parameters:

df - target data folder

Returns:

new primary file of the object

Throws:

IOException - if an error occures

handleCreateShadow

protected DataShadow handleCreateShadow(DataFolder f)
                                 throws IOException

Creates shadow for this object in specified folder (overridable in subclasses).

The default implementation creates a reference data shadow and pastes it into the specified folder.

Parameters:

f - the folder to create a shortcut in

Returns:

the shadow

Throws:

IOException

createShadow

public final DataShadow createShadow(DataFolder f)
                              throws IOException

Creates shadow for this object in specified folder.

An event is fired and atomicity is implemented.

Parameters:

f - the folder to create shortcut in

Returns:

the shadow

Throws:

IOException

createFromTemplate

public final DataObject createFromTemplate(DataFolder f)
                                    throws IOException

Create a new object from template (with a name depending on the template).

Parameters:

f - folder to create object in

Returns:

new data object based on this one

Throws:

IOException - if an error occured

See Also:

DataObject.createFromTemplate(DataFolder,String)

createFromTemplate

public final DataObject createFromTemplate(DataFolder f,
                                           String name)
                                    throws IOException

Create a new object from template. Asks DataObject.handleCreateFromTemplate(org.openide.loaders.DataFolder, java.lang.String).

Parameters:

f - folder to create object in

name - name of object that should be created, or null if the name should be same as that of the template (or otherwise mechanically generated)

Returns:

the new data object

Throws:

IOException - if an error occured

createFromTemplate

public final DataObject createFromTemplate(DataFolder f,
                                           String name,
                                           Map<String,? extends Object> parameters)
                                    throws IOException

More generic way how to instantiate a DataObject. One can not only specify its name, but also pass a map of parameters that can influence the copying of the stream.

Parameters:

f - folder to create object in

name - name of object that should be created, or null if the name should be same as that of the template (or otherwise mechanically generated)

parameters - map of named objects that are going to be used when creating the new object

Returns:

the new data object

Throws:

IOException - if an error occured

Since:

6.1

handleCreateFromTemplate

protected abstract DataObject handleCreateFromTemplate(DataFolder df,
                                                       String name)
                                                throws IOException

Create a new data object from template (implemented in subclasses). This method should copy the content of the template to the destination folder and assign a new name to the new object.

Parameters:

df - data folder to create object in

name - name to give to the new object (or null if the name should be chosen according to the template)

Returns:

the new data object

Throws:

IOException - if an error occured

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener l)

Add a property change listener.

Parameters:

l - the listener to add

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener l)

Remove a property change listener.

Parameters:

l - the listener to remove

firePropertyChange

protected final void firePropertyChange(String name,
                                        Object oldValue,
                                        Object newValue)

Fires property change notification to all listeners registered via DataObject.addPropertyChangeListener(java.beans.PropertyChangeListener).

Parameters:

name - of property

oldValue - old value

newValue - new value

addVetoableChangeListener

public void addVetoableChangeListener(VetoableChangeListener l)

Add a listener to vetoable changes.

Parameters:

l - the listener to add

See Also:

DataObject.PROP_VALID

removeVetoableChangeListener

public void removeVetoableChangeListener(VetoableChangeListener l)

Add a listener to vetoable changes.

Parameters:

l - the listener to remove

See Also:

DataObject.PROP_VALID

fireVetoableChange

protected final void fireVetoableChange(String name,
                                        Object oldValue,
                                        Object newValue)
                                 throws PropertyVetoException

Fires vetoable change notification.

Parameters:

name - of property

oldValue - old value

newValue - new value

Throws:

PropertyVetoException - if the change has been vetoed

getCookie

public <T extends Node.Cookie> T getCookie(Class<T> c)

Obtain a cookie from the data object. May be overridden by subclasses to extend the behaviour of data objects.

The default implementation tests if this object is of the requested class and if so, returns it.

Warning: the DataObject.getCookie(java.lang.Class<T>) method and DataObject.getLookup() method are ment to be interchangable - e.g. if you override one of them be sure to override also the other and try as much as possible to keep the same content in each of them. The default implementation tries to do that as much as possible.

Parameters:

c - class of requested cookie

Returns:

a cookie or null if such cookies are not supported

getLookup

public Lookup getLookup()

Represents a context of the data object. This method is a more general replacement for DataObject.getCookie(java.lang.Class<T>) and should preferably be used instead of the old method. The default implementation inside a data object returns the getNodeDelegate().getLookup() - which is the most compatible behaviour with previous versions. However this code has significant potential to deadlocks. That is why the preferred advice is to override the method to:

 class MyDataObject extends MultiDataObject {
   public @Override Lookup getLookup() {
     return getCookieSet().getLookup();
   }
 }
 

Warning: the DataObject.getCookie(java.lang.Class<T>) method and DataObject.getLookup() method are ment to be interchangable - e.g. if you override one of them be sure to override also the other and try as much as possible to keep the same content in each of them. The default implementation tries to do that as much as possible.

Specified by:

getLookup in interface Lookup.Provider

Returns:

lookup representing this data object and its content

Since:

6.0

getCookie

protected <T extends Node.Cookie> T getCookie(DataShadow shadow,
                                              Class<T> clazz)

When a request for a cookie is done on a DataShadow of this DataObject this methods gets called (by default) so the DataObject knows which DataShadow is asking and extract some information from the shadow itself.

Subclasses can override this method with better logic, but the default implementation just delegates to getCookie (Class).

Parameters:

clazz - class to search for

shadow - the shadow for which is asking

Returns:

the cookie or null

Since:

1.16

writeReplace

public Object writeReplace()

The Serialization replacement for this object stores the primary file instead.

Returns:

a replacement