Package org.eclipse.swt.dnd

Class Transfer

  • Direct Known Subclasses:
    ByteArrayTransfer, ClientFileTransfer
    public abstract class Transfer
extends java.lang.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.

    Since:
    1.3
    See Also:
    ByteArrayTransfer

    • Constructor Summary

      Constructors 
      Constructor Description
      Transfer()  

    • 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 java.lang.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).
      abstract void javaToNative​(java.lang.Object object, TransferData transferData)
      Converts a java representation of data to a platform specific representation of the data.
      abstract java.lang.Object nativeToJava​(TransferData transferData)
      Converts a platform specific representation of data to a java representation.
      static int registerType​(java.lang.String formatName)
      Registers a name for a data type and returns the associated unique identifier.
      protected boolean validate​(java.lang.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 Detail

      • Transfer

        public Transfer()

    • Method Detail

      • 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 java.lang.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

        public abstract void javaToNative​(java.lang.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 to 1. If this transfer agent is unable to perform the conversion, the transferData.result field will be set to a failure value of 0.

        IMPORTANT: This method is not part of the RWT public API. It is marked public only so that it can be shared within the packages provided by RWT. It should never be accessed from application code.

        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

        public abstract java.lang.Object nativeToJava​(TransferData transferData)
        Converts a platform specific representation of data to a java representation.

        IMPORTANT: This method is not part of the RWT public API. It is marked public only so that it can be shared within the packages provided by RWT. It should never be accessed from application code.

        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​(java.lang.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.

        Parameters:
        formatName - the name of a data type
        Returns:
        the unique identifier associated with this data type

      • validate

        protected boolean validate​(java.lang.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