JavaBeans Activation Framework API 1.2.0 · javax.activation.DataHandler

Modifier and Type	Field and Description
private CommandMap	currentCommandMap
private DataContentHandler	dataContentHandler
private DataSource	dataSource
private static final DataFlavor[]	emptyFlavors
private static DataContentHandlerFactory	factory
private DataContentHandler	factoryDCH
private DataSource	objDataSource
private Object	object
private String	objectMimeType
private DataContentHandlerFactory	oldFactory
private String	shortType
private DataFlavor[]	transferFlavors

Access	Constructor and Description
public	DataHandler(DataSource the DataSource ds) Create a `DataHandler` instance referencing the specified DataSource.
public	DataHandler(Object the Java Object obj, String the MIME type of the object mimeType) Create a `DataHandler` instance representing an object of this MIME type.
public	DataHandler(URL a URL object url) Create a `DataHandler` instance referencing a URL.

Method Summary

Modifier and Type	Method and Description
public CommandInfo[]	Returns: the CommandInfo objects representing all the commands getAllCommands() Return all the commands for this type of data.
private synchronized String	getBaseType() Use the MimeType class to extract the MIME type/subtype, ignoring the parameters.
public Object	Returns: the instantiated command object getBean(CommandInfo the CommandInfo corresponding to a command cmdinfo) A convenience method that takes a CommandInfo object and instantiates the corresponding command, usually a JavaBean component.
public CommandInfo	Returns: the CommandInfo corresponding to the command getCommand(String the command name cmdName) Get the command cmdName.
private synchronized CommandMap	getCommandMap() Return the CommandMap for this instance of DataHandler.
public Object	Returns: the content. getContent() Return the data in its preferred Object form.
public String	Returns: the MIME type getContentType() Return the MIME type of this object as retrieved from the source object.
private synchronized DataContentHandler	Returns: the requested DataContentHandler getDataContentHandler() Get the DataContentHandler for this DataHandler: If a DataContentHandlerFactory is set, use it.
public DataSource	Returns: a valid DataSource object for this DataHandler getDataSource() Return the DataSource associated with this instance of DataHandler.
public InputStream	Returns: the InputStream representing this data getInputStream() Get the InputStream for this object.
public String	Returns: the name of the object getName() Return the name of the data object.
public OutputStream	Returns: the OutputStream getOutputStream() Get an OutputStream for this DataHandler to allow overwriting the underlying data.
public CommandInfo[]	Returns: the CommandInfo objects representing the preferred commands getPreferredCommands() Return the preferred commands for this type of data.
public Object	Returns: the object getTransferData(DataFlavor the requested flavor for the data flavor) Implements java.awt.datatransfer.Transferable.getTransferData. Returns an object that represents the data to be transferred.
public synchronized DataFlavor[]	Returns: an array of data flavors in which this data can be transferred getTransferDataFlavors() Implements java.awt.datatransfer.Transferable.getTransferDataFlavors. Return the DataFlavors in which this data is available.
public boolean	Returns: true if the data flavor is supported isDataFlavorSupported(DataFlavor the requested flavor for the data flavor) Implements java.awt.datatransfer.Transferable.isDataFlavorSupported. Returns whether the specified data flavor is supported for this object.
public synchronized void	setCommandMap(CommandMap the CommandMap to use in this DataHandler commandMap) Set the CommandMap for use by this DataHandler.
public static synchronized void	setDataContentHandlerFactory(DataContentHandlerFactory the DataContentHandlerFactory newFactory) Sets the DataContentHandlerFactory.
public void	writeTo(OutputStream the OutputStream to write to os) Write the data to an `OutputStream`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

currentCommandMap	back to summary
private CommandMap currentCommandMap

dataContentHandler	back to summary
private DataContentHandler dataContentHandler

dataSource	back to summary
private DataSource dataSource

emptyFlavors	back to summary
private static final DataFlavor[] emptyFlavors

factory	back to summary
private static DataContentHandlerFactory factory

factoryDCH	back to summary
private DataContentHandler factoryDCH

objDataSource	back to summary
private DataSource objDataSource

object	back to summary
private Object object

objectMimeType	back to summary
private String objectMimeType

oldFactory	back to summary
private DataContentHandlerFactory oldFactory

shortType	back to summary
private String shortType

transferFlavors	back to summary
private DataFlavor[] transferFlavors

DataHandler	back to summary
public DataHandler(DataSource ds) Create a `DataHandler` instance referencing the specified DataSource. The data exists in a byte stream form. The DataSource will provide an InputStream to access the data. Parameters ds:DataSource the DataSource

DataHandler	back to summary
public DataHandler(Object obj, String mimeType) Create a `DataHandler` instance representing an object of this MIME type. This constructor is used when the application already has an in-memory representation of the data in the form of a Java Object. Parameters obj:Object the Java Object mimeType:String the MIME type of the object

DataHandler	back to summary
public DataHandler(URL url) Create a `DataHandler` instance referencing a URL. The DataHandler internally creates a `URLDataSource` instance to represent the URL. Parameters url:URL a URL object

Method Detail

getAllCommands back to summary

getAllCommands	back to summary
public CommandInfo[] getAllCommands() Return all the commands for this type of data. This method returns an array containing all commands for the type of data represented by this DataHandler. The MIME type for the underlying data represented by this DataHandler is used to call through to the `getAllCommands` method of the CommandMap associated with this DataHandler. Returns:CommandInfo[] the CommandInfo objects representing all the commands See Also `javax.activation.CommandMap#getAllCommands`

public CommandInfo[] getAllCommands()

Return all the commands for this type of data. This method returns an array containing all commands for the type of data represented by this DataHandler. The MIME type for the underlying data represented by this DataHandler is used to call through to the getAllCommands method of the CommandMap associated with this DataHandler.

Returns:CommandInfo[]: the CommandInfo objects representing all the commands
See Also: javax.activation.CommandMap#getAllCommands

getBaseType	back to summary
private synchronized String getBaseType() Use the MimeType class to extract the MIME type/subtype, ignoring the parameters. The type is cached.

getBean back to summary

getBean	back to summary
public Object getBean(CommandInfo cmdinfo) A convenience method that takes a CommandInfo object and instantiates the corresponding command, usually a JavaBean component. This method calls the CommandInfo's `getCommandObject` method with the `ClassLoader` used to load the `javax.activation.DataHandler` class itself. Parameters cmdinfo:CommandInfo the CommandInfo corresponding to a command Returns:Object the instantiated command object

public Object getBean(CommandInfo cmdinfo)

A convenience method that takes a CommandInfo object and instantiates the corresponding command, usually a JavaBean component.

This method calls the CommandInfo's getCommandObject method with the ClassLoader used to load the javax.activation.DataHandler class itself.

Parameters

cmdinfo:CommandInfo: the CommandInfo corresponding to a command

Returns:Object

the instantiated command object

getCommand back to summary

getCommand	back to summary
public CommandInfo getCommand(String cmdName) Get the command cmdName. Use the search semantics as defined by the CommandMap installed in this DataHandler. The MIME type for the underlying data represented by this DataHandler is used to call through to the `getCommand` method of the CommandMap associated with this DataHandler. Parameters cmdName:String the command name Returns:CommandInfo the CommandInfo corresponding to the command See Also `javax.activation.CommandMap#getCommand`

public CommandInfo getCommand(String cmdName)

Get the command cmdName. Use the search semantics as defined by the CommandMap installed in this DataHandler. The MIME type for the underlying data represented by this DataHandler is used to call through to the getCommand method of the CommandMap associated with this DataHandler.

Parameters

cmdName:String: the command name

Returns:CommandInfo

the CommandInfo corresponding to the command

getCommandMap	back to summary
private synchronized CommandMap getCommandMap() Return the CommandMap for this instance of DataHandler.

getContent back to summary

getContent	back to summary
public Object getContent() throws IOException Return the data in its preferred Object form. If the DataHandler was instantiated with an object, return the object. If the DataHandler was instantiated with a DataSource, this method uses a DataContentHandler to return the content object for the data represented by this DataHandler. If no `DataContentHandler` can be found for the the type of this data, the DataHandler returns an InputStream for the data. Returns:Object the content. Exceptions IOException: if an IOException occurs during this operation.

public Object getContent() throws IOException

Return the data in its preferred Object form.

If the DataHandler was instantiated with an object, return the object.

If the DataHandler was instantiated with a DataSource, this method uses a DataContentHandler to return the content object for the data represented by this DataHandler. If no DataContentHandler can be found for the the type of this data, the DataHandler returns an InputStream for the data.

Returns:Object

the content.

Exceptions

IOException:: if an IOException occurs during this operation.

getContentType	back to summary
public String getContentType() Return the MIME type of this object as retrieved from the source object. Note that this is the full type with parameters. Returns:String the MIME type

getContentType

back to summary

public String getContentType()

Return the MIME type of this object as retrieved from the source object. Note that this is the full type with parameters.

Returns:String: the MIME type

getDataContentHandler	back to summary
private synchronized DataContentHandler getDataContentHandler() Get the DataContentHandler for this DataHandler: If a DataContentHandlerFactory is set, use it. Otherwise look for an object to serve DCH in the following order: 1) if a factory is set, use it 2) if a CommandMap is set, use it 3) use the default CommandMap In any case, wrap the real DataContentHandler with one of our own to handle any missing cases, fill in defaults, and to ensure that we always have a non-null DataContentHandler. Returns:DataContentHandler the requested DataContentHandler

getDataContentHandler

back to summary

private synchronized DataContentHandler getDataContentHandler()

Get the DataContentHandler for this DataHandler:

If a DataContentHandlerFactory is set, use it. Otherwise look for an object to serve DCH in the following order:

1) if a factory is set, use it

2) if a CommandMap is set, use it

3) use the default CommandMap

In any case, wrap the real DataContentHandler with one of our own to handle any missing cases, fill in defaults, and to ensure that we always have a non-null DataContentHandler.

Returns:DataContentHandler: the requested DataContentHandler

getDataSource	back to summary
public DataSource getDataSource() Return the DataSource associated with this instance of DataHandler. For DataHandlers that have been instantiated with a DataSource, this method returns the DataSource that was used to create the DataHandler object. In other cases the DataHandler constructs a DataSource from the data used to construct the DataHandler. DataSources created for DataHandlers not instantiated with a DataSource are cached for performance reasons. Returns:DataSource a valid DataSource object for this DataHandler

getDataSource

back to summary

public DataSource getDataSource()

Return the DataSource associated with this instance of DataHandler.

For DataHandlers that have been instantiated with a DataSource, this method returns the DataSource that was used to create the DataHandler object. In other cases the DataHandler constructs a DataSource from the data used to construct the DataHandler. DataSources created for DataHandlers not instantiated with a DataSource are cached for performance reasons.

Returns:DataSource: a valid DataSource object for this DataHandler

getInputStream back to summary

getInputStream	back to summary
public InputStream getInputStream() throws IOException Get the InputStream for this object. For DataHandlers instantiated with a DataSource, the DataHandler calls the `DataSource.getInputStream` method and returns the result to the caller. For DataHandlers instantiated with an Object, the DataHandler first attempts to find a DataContentHandler for the Object. If the DataHandler can not find a DataContentHandler for this MIME type, it throws an UnsupportedDataTypeException. If it is successful, it creates a pipe and a thread. The thread uses the DataContentHandler's `writeTo` method to write the stream data into one end of the pipe. The other end of the pipe is returned to the caller. Because a thread is created to copy the data, IOExceptions that may occur during the copy can not be propagated back to the caller. The result is an empty stream. Returns:InputStream the InputStream representing this data Exceptions IOException: if an I/O error occurs See Also `javax.activation.DataContentHandler#writeTo`, `javax.activation.UnsupportedDataTypeException`

public InputStream getInputStream() throws IOException

Get the InputStream for this object.

For DataHandlers instantiated with a DataSource, the DataHandler calls the DataSource.getInputStream method and returns the result to the caller.

For DataHandlers instantiated with an Object, the DataHandler first attempts to find a DataContentHandler for the Object. If the DataHandler can not find a DataContentHandler for this MIME type, it throws an UnsupportedDataTypeException. If it is successful, it creates a pipe and a thread. The thread uses the DataContentHandler's writeTo method to write the stream data into one end of the pipe. The other end of the pipe is returned to the caller. Because a thread is created to copy the data, IOExceptions that may occur during the copy can not be propagated back to the caller. The result is an empty stream.

Returns:InputStream

the InputStream representing this data

Exceptions

IOException:: if an I/O error occurs

getName back to summary

getName	back to summary
public String getName() Return the name of the data object. If this DataHandler was created with a DataSource, this method calls through to the `DataSource.getName` method, otherwise it returns null. Returns:String the name of the object

public String getName()

Return the name of the data object. If this DataHandler was created with a DataSource, this method calls through to the DataSource.getName method, otherwise it returns null.

Returns:String: the name of the object

getOutputStream back to summary

getOutputStream	back to summary
public OutputStream getOutputStream() throws IOException Get an OutputStream for this DataHandler to allow overwriting the underlying data. If the DataHandler was created with a DataSource, the DataSource's `getOutputStream` method is called. Otherwise, `null` is returned. Returns:OutputStream the OutputStream Exceptions IOException: for failures creating the OutputStream See Also `javax.activation.DataSource#getOutputStream`, `javax.activation.URLDataSource`

public OutputStream getOutputStream() throws IOException

Get an OutputStream for this DataHandler to allow overwriting the underlying data. If the DataHandler was created with a DataSource, the DataSource's getOutputStream method is called. Otherwise, null is returned.

Returns:OutputStream

the OutputStream

Exceptions

IOException:: for failures creating the OutputStream

getPreferredCommands back to summary

getPreferredCommands	back to summary
public CommandInfo[] getPreferredCommands() Return the preferred commands for this type of data. This method calls the `getPreferredCommands` method in the CommandMap associated with this instance of DataHandler. This method returns an array that represents a subset of available commands. In cases where multiple commands for the MIME type represented by this DataHandler are present, the installed CommandMap chooses the appropriate commands. Returns:CommandInfo[] the CommandInfo objects representing the preferred commands See Also `javax.activation.CommandMap#getPreferredCommands`

public CommandInfo[] getPreferredCommands()

Return the preferred commands for this type of data. This method calls the getPreferredCommands method in the CommandMap associated with this instance of DataHandler. This method returns an array that represents a subset of available commands. In cases where multiple commands for the MIME type represented by this DataHandler are present, the installed CommandMap chooses the appropriate commands.

Returns:CommandInfo[]: the CommandInfo objects representing the preferred commands
See Also: javax.activation.CommandMap#getPreferredCommands

getTransferData back to summary

getTransferData	back to summary
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException Implements java.awt.datatransfer.Transferable.getTransferData. Returns an object that represents the data to be transferred. The class of the object returned is defined by the representation class of the data flavor. For DataHandler's created with DataSources or URLs: The DataHandler attempts to locate a DataContentHandler for this MIME type. If one is found, the passed in DataFlavor and the type of the data are passed to its `getTransferData` method. If the DataHandler fails to locate a DataContentHandler and the flavor specifies this object's MIME type and the `java.io.InputStream` class, this object's InputStream is returned. Otherwise it throws an UnsupportedFlavorException. For DataHandler's created with Objects: The DataHandler attempts to locate a DataContentHandler for this MIME type. If one is found, the passed in DataFlavor and the type of the data are passed to its getTransferData method. If the DataHandler fails to locate a DataContentHandler and the flavor specifies this object's MIME type and its class, this DataHandler's referenced object is returned. Otherwise it throws an UnsupportedFlavorException. Parameters flavor:DataFlavor the requested flavor for the data Returns:Object the object Exceptions UnsupportedFlavorException: if the data could not be converted to the requested flavor IOException: if an I/O error occurs See Also `javax.activation.ActivationDataFlavor`

public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException

Implements java.awt.datatransfer.Transferable.getTransferData.

Returns an object that represents the data to be transferred. The class of the object returned is defined by the representation class of the data flavor.

For DataHandler's created with DataSources or URLs:

The DataHandler attempts to locate a DataContentHandler for this MIME type. If one is found, the passed in DataFlavor and the type of the data are passed to its getTransferData method. If the DataHandler fails to locate a DataContentHandler and the flavor specifies this object's MIME type and the java.io.InputStream class, this object's InputStream is returned. Otherwise it throws an UnsupportedFlavorException.

For DataHandler's created with Objects:

The DataHandler attempts to locate a DataContentHandler for this MIME type. If one is found, the passed in DataFlavor and the type of the data are passed to its getTransferData method. If the DataHandler fails to locate a DataContentHandler and the flavor specifies this object's MIME type and its class, this DataHandler's referenced object is returned. Otherwise it throws an UnsupportedFlavorException.

Parameters

flavor:DataFlavor: the requested flavor for the data

Returns:Object

the object

Exceptions

UnsupportedFlavorException:: if the data could not be converted to the requested flavor
IOException:: if an I/O error occurs

See Also

javax.activation.ActivationDataFlavor

getTransferDataFlavors back to summary

getTransferDataFlavors	back to summary
public synchronized DataFlavor[] getTransferDataFlavors() Implements java.awt.datatransfer.Transferable.getTransferDataFlavors. Return the DataFlavors in which this data is available. Returns an array of DataFlavor objects indicating the flavors the data can be provided in. The array is usually ordered according to preference for providing the data, from most richly descriptive to least richly descriptive. The DataHandler attempts to find a DataContentHandler that corresponds to the MIME type of the data. If one is located, the DataHandler calls the DataContentHandler's `getTransferDataFlavors` method. If a DataContentHandler can not be located, and if the DataHandler was created with a DataSource (or URL), one DataFlavor is returned that represents this object's MIME type and the `java.io.InputStream` class. If the DataHandler was created with an object and a MIME type, getTransferDataFlavors returns one DataFlavor that represents this object's MIME type and the object's class. Returns:DataFlavor[] an array of data flavors in which this data can be transferred See Also `javax.activation.DataContentHandler#getTransferDataFlavors`

public synchronized DataFlavor[] getTransferDataFlavors()

Implements java.awt.datatransfer.Transferable.getTransferDataFlavors.

Return the DataFlavors in which this data is available.

Returns an array of DataFlavor objects indicating the flavors the data can be provided in. The array is usually ordered according to preference for providing the data, from most richly descriptive to least richly descriptive.

The DataHandler attempts to find a DataContentHandler that corresponds to the MIME type of the data. If one is located, the DataHandler calls the DataContentHandler's getTransferDataFlavors method.

If a DataContentHandler can not be located, and if the DataHandler was created with a DataSource (or URL), one DataFlavor is returned that represents this object's MIME type and the java.io.InputStream class. If the DataHandler was created with an object and a MIME type, getTransferDataFlavors returns one DataFlavor that represents this object's MIME type and the object's class.

Returns:DataFlavor[]: an array of data flavors in which this data can be transferred
See Also: javax.activation.DataContentHandler#getTransferDataFlavors

isDataFlavorSupported back to summary

isDataFlavorSupported	back to summary
public boolean isDataFlavorSupported(DataFlavor flavor) Implements java.awt.datatransfer.Transferable.isDataFlavorSupported. Returns whether the specified data flavor is supported for this object. This method iterates through the DataFlavors returned from `getTransferDataFlavors`, comparing each with the specified flavor. Parameters flavor:DataFlavor the requested flavor for the data Returns:boolean true if the data flavor is supported See Also `javax.activation.DataHandler#getTransferDataFlavors`

public boolean isDataFlavorSupported(DataFlavor flavor)

Implements java.awt.datatransfer.Transferable.isDataFlavorSupported.

Returns whether the specified data flavor is supported for this object.

This method iterates through the DataFlavors returned from getTransferDataFlavors, comparing each with the specified flavor.

Parameters

flavor:DataFlavor: the requested flavor for the data

Returns:boolean

true if the data flavor is supported

setCommandMap back to summary

setCommandMap	back to summary
public synchronized void setCommandMap(CommandMap commandMap) Set the CommandMap for use by this DataHandler. Setting it to `null` causes the CommandMap to revert to the CommandMap returned by the `CommandMap.getDefaultCommandMap` method. Changing the CommandMap, or setting it to `null`, clears out any data cached from the previous CommandMap. Parameters commandMap:CommandMap the CommandMap to use in this DataHandler See Also `javax.activation.CommandMap#setDefaultCommandMap`

public synchronized void setCommandMap(CommandMap commandMap)

Set the CommandMap for use by this DataHandler. Setting it to null causes the CommandMap to revert to the CommandMap returned by the CommandMap.getDefaultCommandMap method. Changing the CommandMap, or setting it to null, clears out any data cached from the previous CommandMap.

Parameters

commandMap:CommandMap: the CommandMap to use in this DataHandler

setDataContentHandlerFactory back to summary

setDataContentHandlerFactory	back to summary
public static synchronized void setDataContentHandlerFactory(DataContentHandlerFactory newFactory) Sets the DataContentHandlerFactory. The DataContentHandlerFactory is called first to find DataContentHandlers. The DataContentHandlerFactory can only be set once. If the DataContentHandlerFactory has already been set, this method throws an Error. Parameters newFactory:DataContentHandlerFactory the DataContentHandlerFactory Exceptions Error: if the factory has already been defined. See Also `javax.activation.DataContentHandlerFactory`

public static synchronized void setDataContentHandlerFactory(DataContentHandlerFactory newFactory)

Sets the DataContentHandlerFactory. The DataContentHandlerFactory is called first to find DataContentHandlers. The DataContentHandlerFactory can only be set once.

If the DataContentHandlerFactory has already been set, this method throws an Error.

Parameters

newFactory:DataContentHandlerFactory: the DataContentHandlerFactory

Exceptions

Error:: if the factory has already been defined.

writeTo back to summary

writeTo	back to summary
public void writeTo(OutputStream os) throws IOException Write the data to an `OutputStream`. If the DataHandler was created with a DataSource, writeTo retrieves the InputStream and copies the bytes from the InputStream to the OutputStream passed in. If the DataHandler was created with an object, writeTo retrieves the DataContentHandler for the object's type. If the DataContentHandler was found, it calls the `writeTo` method on the `DataContentHandler`. Parameters os:OutputStream the OutputStream to write to Exceptions IOException: if an I/O error occurs

public void writeTo(OutputStream os) throws IOException

Write the data to an OutputStream.

If the DataHandler was created with a DataSource, writeTo retrieves the InputStream and copies the bytes from the InputStream to the OutputStream passed in.

If the DataHandler was created with an object, writeTo retrieves the DataContentHandler for the object's type. If the DataContentHandler was found, it calls the writeTo method on the DataContentHandler.

Parameters

os:OutputStream: the OutputStream to write to

Exceptions

IOException:: if an I/O error occurs

public Class DataHandler

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