Package org.eclipse.swt.dnd
Class Transfer
- java.lang.Object
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- org.eclipse.swt.dnd.Transfer
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- Direct Known Subclasses:
ByteArrayTransfer
public abstract class Transfer extends Object
Transferprovides a mechanism for converting between a java representation of data and a platform specific representation of data and vice versa. It is used in data transfer operations such as drag and drop and clipboard copy/paste.You should only need to become familiar with this class if you are implementing a Transfer subclass and you are unable to subclass the ByteArrayTransfer class.
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Constructor Summary
Constructors Constructor Description Transfer()
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description abstract TransferData[]getSupportedTypes()Returns a list of the platform specific data types that can be converted using this transfer agent.protected abstract int[]getTypeIds()Returns the platform specific ids of the data types that can be converted using this transfer agent.protected abstract String[]getTypeNames()Returns the platform specific names of the data types that can be converted using this transfer agent.abstract booleanisSupportedType(TransferData transferData)Returns true if theTransferDatadata type can be converted using this transfer agent, or false otherwise (including if transferData isnull).protected abstract voidjavaToNative(Object object, TransferData transferData)Converts a java representation of data to a platform specific representation of the data.protected abstract ObjectnativeToJava(TransferData transferData)Converts a platform specific representation of data to a java representation.static intregisterType(String formatName)Registers a name for a data type and returns the associated unique identifier.protected booleanvalidate(Object object)Test that the object is of the correct format for this Transfer class.
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Method Detail
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getSupportedTypes
public abstract TransferData[] getSupportedTypes()
Returns a list of the platform specific data types that can be converted using this transfer agent.Only the data type fields of the
TransferDataobjects are filled in.- Returns:
- a list of the data types that can be converted using this transfer agent
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isSupportedType
public abstract boolean isSupportedType(TransferData transferData)
Returns true if theTransferDatadata type can be converted using this transfer agent, or false otherwise (including if transferData isnull).- Parameters:
transferData- a platform specific description of a data type; only the data type fields of theTransferDataobject need to be filled in- Returns:
- true if the transferData data type can be converted using this transfer agent
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getTypeIds
protected abstract int[] getTypeIds()
Returns the platform specific ids of the data types that can be converted using this transfer agent.- Returns:
- the platform specific ids of the data types that can be converted using this transfer agent
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getTypeNames
protected abstract String[] getTypeNames()
Returns the platform specific names of the data types that can be converted using this transfer agent.- Returns:
- the platform specific names of the data types that can be converted using this transfer agent.
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javaToNative
protected abstract void javaToNative(Object object, TransferData transferData)
Converts a java representation of data to a platform specific representation of the data.On a successful conversion, the transferData.result field will be set as follows:
- Windows: COM.S_OK
- GTK: 1
If this transfer agent is unable to perform the conversion, the transferData.result field will be set to a failure value as follows:
- Windows: COM.DV_E_TYMED or COM.E_FAIL
- GTK: 0
- Parameters:
object- a java representation of the data to be converted; the type of Object that is passed in is dependent on theTransfersubclass.transferData- an empty TransferData object; this object will be filled in on return with the platform specific representation of the data- Throws:
SWTException-- ERROR_INVALID_DATA - if object does not contain data in a valid format or is
null
- ERROR_INVALID_DATA - if object does not contain data in a valid format or is
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nativeToJava
protected abstract Object nativeToJava(TransferData transferData)
Converts a platform specific representation of data to a java representation.- Parameters:
transferData- the platform specific representation of the data to be converted- Returns:
- a java representation of the converted data if the conversion was
successful; otherwise null. If transferData is
nullthennullis returned. The type of Object that is returned is dependent on theTransfersubclass.
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registerType
public static int registerType(String formatName)
Registers a name for a data type and returns the associated unique identifier.You may register the same type more than once, the same unique identifier will be returned if the type has been previously registered.
Note: On windows, do not call this method with pre-defined Clipboard Format types such as CF_TEXT or CF_BITMAP because the pre-defined identifier will not be returned
- Parameters:
formatName- the name of a data type- Returns:
- the unique identifier associated with this data type
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validate
protected boolean validate(Object object)
Test that the object is of the correct format for this Transfer class.- Parameters:
object- a java representation of the data to be converted- Returns:
- true if object is of the correct form for this transfer type
- Since:
- 3.1
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