DataLoaderPool (Datasystems API)

java.lang.Object
- org.openide.loaders.DataLoaderPool

All Implemented Interfaces:

Serializable
```
public abstract class DataLoaderPool
extends Object
implements Serializable
```
Pool of data loaders. Provides access to set of registered loaders in the system. They are used to find valid data objects for given files.
The default instance can be retrieved using lookup.

See Also:

Serialized Form

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`DataLoaderPool()` Create new loader pool.
`protected`	`DataLoaderPool(DataLoader loader)` Create new loader pool and set preferred loader.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addChangeListener(ChangeListener chl)` Add a new listener to the listener list.
`void`	`addOperationListener(OperationListener l)` Add a listener for operations on data objects.
`Enumeration<DataLoader>`	`allLoaders()` Get an enumeration of all loaders, including the preferred and system loaders.
`static OperationListener`	`createWeakOperationListener(OperationListener l, Object s)` Factory to create weak OperationListener
`static <T extends DataObject> DataObject.Factory`	`factory(Class<T> dataObjectClass, String mimeType, Image image)` Factory method to create default implementation of a factory for data objects.
`DataObject`	`findDataObject(FileObject fo)` Find a data object for this file object (not for normal users of the APIs).
`DataObject`	`findDataObject(FileObject fo, DataLoader.RecognizedFiles r)` Find a data object for this file object, considering already-recognized files (not for normal users of the APIs).
`protected void`	`fireChangeEvent(ChangeEvent che)` Fire change event to all listeners.
`DataLoader`	`firstProducerOf(Class<? extends DataObject> clazz)` Finds the first producer of a representation class.
`static DataLoaderPool`	`getDefault()` Getter for the default pool of loaders used in the system.
`static DataLoader`	`getPreferredLoader(FileObject fo)` Get the preferred loader for a file.
`protected abstract Enumeration<? extends DataLoader>`	`loaders()` Get an enumeration of data loaders.
`Enumeration<DataLoader>`	`producersOf(Class<? extends DataObject> clazz)` Get an enumeration of all producers of a representation class.
`void`	`removeChangeListener(ChangeListener chl)` Remove a listener from the listener list.
`void`	`removeOperationListener(OperationListener l)` Remove a listener for operations on data objects.
`static void`	`setPreferredLoader(FileObject fo, DataLoader loader)` Utility method to mark a file as belonging to a loader.
`DataLoader[]`	`toArray()` Get an array of loaders that are currently registered.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DataLoaderPool
```
protected DataLoaderPool()
```
    Create new loader pool.
  - DataLoaderPool
```
protected DataLoaderPool(DataLoader loader)
```
    Create new loader pool and set preferred loader. The preferred loader will be asked before any other to recognize files (also before the system loader).
    
    Parameters:
    
    loader - the preferred loader
- Method Detail
  - getDefault
```
public static DataLoaderPool getDefault()
```
    Getter for the default pool of loaders used in the system. By default it looks it up using Lookup, if not found it provides default one that does lookup individual loaders using Lookup.
    
    Returns:
    
    instance of system DataLoaderPool
    
    Since:
    
    5.1
  - loaders
```
protected abstract Enumeration<? extends DataLoader> loaders()
```
    Get an enumeration of data loaders. Must be overridden in subclasses to provide a list of additional loaders. The list should not include the preferred loader.
    
    Returns:
    
    enumeration of loaders
  - addChangeListener
```
public final void addChangeListener(ChangeListener chl)
```
    Add a new listener to the listener list. A listener is notified of any change which was made to the loader pool (add, remove, or reorder).
    
    Parameters:
    
    chl - new listener
  - removeChangeListener
```
public final void removeChangeListener(ChangeListener chl)
```
    Remove a listener from the listener list.
    
    Parameters:
    
    chl - listener to remove
  - fireChangeEvent
```
protected final void fireChangeEvent(ChangeEvent che)
```
    Fire change event to all listeners. Asynchronously.
    
    Parameters:
    
    che - change event
  - createWeakOperationListener
```
public static OperationListener createWeakOperationListener(OperationListener l,
                                                            Object s)
```
    Factory to create weak OperationListener
    
    Parameters:
    
    l - listener
    
    s - the source the new listener will be attached to
  - addOperationListener
```
public final void addOperationListener(OperationListener l)
```
    Add a listener for operations on data objects.
    
    Parameters:
    
    l - the listener
  - removeOperationListener
```
public final void removeOperationListener(OperationListener l)
```
    Remove a listener for operations on data objects.
    
    Parameters:
    
    l - the listener
  - allLoaders
```
public final Enumeration<DataLoader> allLoaders()
```
    Get an enumeration of all loaders, including the preferred and system loaders. This should be the list of loaders as actually used by the system. Typically it will consist of, in this order:
    1. The preferred loader, if any.
    2. The system loaders, such as may be used for folders, shadows, etc.
    3. Module-specified loaders.
    4. The loader for instance data objects.
    5. Default loaders, which may handle files not otherwise recognizable.
    Applications should not rely on the exact contents of the pool, rather the fact that this contains all the loaders which are capable of recognizing files in the order in which they are called.
    Returns:
    
    enumeration of loaders
  - toArray
```
public DataLoader[] toArray()
```
    Get an array of loaders that are currently registered. Does not include special system loaders, etc.
    
    Returns:
    
    array of loaders
    
    See Also:
    
    DataLoaderPool.loaders()
  - firstProducerOf
```
public final DataLoader firstProducerOf(Class<? extends DataObject> clazz)
```
    Finds the first producer of a representation class. Scans through the list of all loaders and returns the first one whose representation class is a superclass of clazz.
    
    Parameters:
    
    clazz - class to find producer for
    
    Returns:
    
    data loader or null if there is no loader that can produce the class
  - producersOf
```
public final Enumeration<DataLoader> producersOf(Class<? extends DataObject> clazz)
```
    Get an enumeration of all producers of a representation class.
    
    Parameters:
    
    clazz - class to find producers for
    
    Returns:
    
    enumeration of loaders
    
    See Also:
    
    DataLoaderPool.firstProducerOf(java.lang.Class<? extends org.openide.loaders.DataObject>)
  - findDataObject
```
public DataObject findDataObject(FileObject fo)
                          throws IOException
```
    Find a data object for this file object (not for normal users of the APIs). DO NOT USE THIS as a normal user of the APIs! Unless you really know what you are doing, use DataObject.find(org.openide.filesystems.FileObject) instead. This call will throw an exception if it already exists, and it is normally only for use by the loader infrastructure.
    All loaders are asked to recognize it according to their priority.
    
    Parameters:
    
    fo - file object to recognize
    
    Returns:
    
    the data object for this object or null if no loader recognizes this file
    
    Throws:
    
    DataObjectExistsException - if the object for this primary file already exists
    
    IOException - if the data object is recognized but an error occurs during instantiation
    
    See Also:
    
    DataLoaderPool.findDataObject(FileObject, DataLoader.RecognizedFiles)
  - findDataObject
```
public DataObject findDataObject(FileObject fo,
                                 DataLoader.RecognizedFiles r)
                          throws IOException
```
    Find a data object for this file object, considering already-recognized files (not for normal users of the APIs). DO NOT USE THIS as a normal user of the APIs! Unless you really know what you are doing, use DataObject.find(org.openide.filesystems.FileObject) instead. This call will throw an exception if it already exists, and it is normally only for use by the loader infrastructure.
    First of all looks at the file extended attribute NetBeansDataLoader; if it is set and it contains the class name of a valid DataLoader, that loader is given preference. For all loaders used, the first to return non-null from DataLoader.findDataObject(org.openide.filesystems.FileObject, java.util.Set<? super org.openide.filesystems.FileObject>) is used.
    
    Parameters:
    
    fo - file object to recognize
    
    r - recognized files buffer
    
    Returns:
    
    the data object for this object
    
    Throws:
    
    DataObjectExistsException - if the object for this primary file already exists
    
    IOException - if the data object is recognized but an error occurs during instantiation
  - setPreferredLoader
```
public static void setPreferredLoader(FileObject fo,
                                      DataLoader loader)
                               throws IOException
```
    Utility method to mark a file as belonging to a loader. When the file is to be recognized this loader will be used first.
    
    Parameters:
    
    fo - file to mark
    
    loader - the loader to assign to the file or null if previous association should be cleared
    
    Throws:
    
    IOException - if setting the file's attribute failed
  - getPreferredLoader
```
public static DataLoader getPreferredLoader(FileObject fo)
```
    Get the preferred loader for a file.
    
    Parameters:
    
    fo - the file to get loader from
    
    Returns:
    
    the loader or null if there is no particular preferred loader
  - factory
```
public static <T extends DataObject> DataObject.Factory factory(Class<T> dataObjectClass,
                                                                String mimeType,
                                                                Image image)
```
    Factory method to create default implementation of a factory for data objects. It takes the class of the DataObject and is ready to call its constructor. The constructor needs to take two arguments: FileObject and MultiFileLoader. It can throw IOException as is usual among DataObject constructors.
    You can also invoke this method from a layer by following definition:
```
 <file name="nameofyourfile.instance">
   <attr name="instanceCreate" methodvalue="org.openide.loaders.DataLoaderPool.factory"/>
   <attr name="dataObjectClass" stringvalue="org.your.pkg.YourDataObject"/>
   <attr name="mimeType" stringvalue="yourmime/type"/>
   <attr name="iconBase" stringvalue="org/your/pkg/YourDataObject.png"/>
 </file>
 
```
    Parameters:
    
    dataObjectClass - the class of the data object to create. Must have appropriate constructor.
    
    mimeType - the mime type associated with the object, used for example to create the right actions for the object's node
    
    image - icon to use by default for nodes representing data objects created with this factory
    
    Returns:
    
    factory to be registered in Loaders/mime/type/Factories in some module layer file
    
    Since:
    
    7.1

Class DataLoaderPool

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DataLoaderPool

DataLoaderPool

Method Detail

getDefault

loaders

addChangeListener

removeChangeListener

fireChangeEvent

createWeakOperationListener

addOperationListener

removeOperationListener

allLoaders

toArray

firstProducerOf

producersOf

findDataObject

findDataObject

setPreferredLoader

getPreferredLoader

factory