Package org.eclipse.swt.dnd

Class Transfer

java.lang.Object
org.eclipse.swt.dnd.Transfer
Direct Known Subclasses:
ByteArrayTransfer
public abstract class Transfer extends Object
Transfer provides 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.

See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    Transfer()
     

  • Method Summary

    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 boolean
    isSupportedType(TransferData transferData)
    Returns true if the TransferData data type can be converted using this transfer agent, or false otherwise (including if transferData is null).
    protected abstract void
    javaToNative(Object object, TransferData transferData)
    Converts a java representation of data to a platform specific representation of the data.
    protected abstract Object
    nativeToJava(TransferData transferData)
    Converts a platform specific representation of data to a java representation.
    static int
    registerType(String formatName)
    Registers a name for a data type and returns the associated unique identifier.
    protected boolean
    validate(Object object)
    Test that the object is of the correct format for this Transfer class.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Transfer

      public Transfer()

  • Method Details

    • 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 TransferData objects are filled in.

      Returns:
      a list of the data types that can be converted using this transfer agent

    • isSupportedType

      public abstract boolean isSupportedType(TransferData transferData)
      Returns true if the TransferData data type can be converted using this transfer agent, or false otherwise (including if transferData is null).
      Parameters:
      transferData - a platform specific description of a data type; only the data type fields of the TransferData object need to be filled in
      Returns:
      true if the transferData data type can be converted using this transfer agent

    • 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

    • 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.

    • 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 the Transfer subclass.
      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

    • 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 null then null is returned. The type of Object that is returned is dependent on the Transfer subclass.

    • 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

    • 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