org.eclipse.jface.util.LocalSelectionTransfer Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jface Show documentation

JFace is a UI toolkit with classes for handling many common UI programming tasks. JFace is window-system-independent in both its API and implementation, and is designed to work with SWT without hiding it. JFace includes the usual UI toolkit components of image and font registries, text, dialog, preference and wizard frameworks, and progress reporting for long running operations. Two of its more interesting features are actions and viewers. The action mechanism allows user commands to be defined independently from their exact whereabouts in the UI. Viewers are model based adapters for certain SWT widgets, simplifying the presentation of application data structured as lists, tables or trees.

The newest version!

/*******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.util;


import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.dnd.ByteArrayTransfer;
import org.eclipse.swt.dnd.TransferData;

/**
 * A LocalSelectionTransfer may be used for drag and drop operations
 * within the same instance of Eclipse.
 * The selection is made available directly for use in the DropTargetListener.
 * dropAccept method. The DropTargetEvent passed to dropAccept does not contain
 * the drop data. The selection may be used for validation purposes so that the
 * drop can be aborted if appropriate.
 *
 * This class is not intended to be subclassed.
 * 
 * @since 3.2
 */
public class LocalSelectionTransfer extends ByteArrayTransfer {

    // First attempt to create a UUID for the type name to make sure that
    // different Eclipse applications use different "types" of
    // LocalSelectionTransfer
    private static final String TYPE_NAME = "local-selection-transfer-format" + (new Long(System.currentTimeMillis())).toString(); //$NON-NLS-1$;

    private static final int TYPEID = registerType(TYPE_NAME);

    private static final LocalSelectionTransfer INSTANCE = new LocalSelectionTransfer();

    private ISelection selection;

    private long selectionSetTime;

    /**
     * Only the singleton instance of this class may be used. 
     */
    protected LocalSelectionTransfer() {
    	// do nothing
    }

    /**
     * Returns the singleton.
     * 
     * @return the singleton
     */
    public static LocalSelectionTransfer getTransfer() {
        return INSTANCE;
    }

    /**
     * Returns the local transfer data.
     * 
     * @return the local transfer data
     */
    public ISelection getSelection() {
        return selection;
    }

    /**
     * Tests whether native drop data matches this transfer type.
     * 
     * @param result result of converting the native drop data to Java
     * @return true if the native drop data does not match this transfer type.
     * 	false otherwise.
     */
    private boolean isInvalidNativeType(Object result) {
        return !(result instanceof byte[])
                || !TYPE_NAME.equals(new String((byte[]) result));
    }

    /**
     * Returns the type id used to identify this transfer.
     * 
     * @return the type id used to identify this transfer.
     */
    protected int[] getTypeIds() {
        return new int[] { TYPEID };
    }

    /**
     * Returns the type name used to identify this transfer.
     * 
     * @return the type name used to identify this transfer.
     */
    protected String[] getTypeNames() {
        return new String[] { TYPE_NAME };
    }

    /**
     * Overrides org.eclipse.swt.dnd.ByteArrayTransfer#javaToNative(Object,
     * TransferData).
     * Only encode the transfer type name since the selection is read and
     * written in the same process.
     * 
     * @see org.eclipse.swt.dnd.ByteArrayTransfer#javaToNative(java.lang.Object, org.eclipse.swt.dnd.TransferData)
     */
    public void javaToNative(Object object, TransferData transferData) {
        byte[] check = TYPE_NAME.getBytes();
        super.javaToNative(check, transferData);
    }

    /**
     * Overrides org.eclipse.swt.dnd.ByteArrayTransfer#nativeToJava(TransferData).
     * Test if the native drop data matches this transfer type.
     * 
     * @see org.eclipse.swt.dnd.ByteArrayTransfer#nativeToJava(TransferData)
     */
    public Object nativeToJava(TransferData transferData) {
        Object result = super.nativeToJava(transferData);
        if (isInvalidNativeType(result)) {
        	Policy.getLog().log(new Status(
                            IStatus.ERROR,
                            Policy.JFACE,
                            IStatus.ERROR,
                            JFaceResources.getString("LocalSelectionTransfer.errorMessage"), null)); //$NON-NLS-1$
        }
        return selection;
    }

    /**
     * Sets the transfer data for local use.
     * 
     * @param s the transfer data
     */
    public void setSelection(ISelection s) {
        selection = s;
    }

    /**
     * Returns the time when the selection operation
     * this transfer is associated with was started.
     * 
     * @return the time when the selection operation has started
     * 
     * @see org.eclipse.swt.events.TypedEvent#time
     */
    public long getSelectionSetTime() {
        return selectionSetTime;
    }

    /**
     * Sets the time when the selection operation this
     * transfer is associated with was started.
     * If assigning this from an SWT event, be sure to use
     * setSelectionTime(event.time & 0xFFFF)
     * 
     * @param time the time when the selection operation was started
     * 
     * @see org.eclipse.swt.events.TypedEvent#time
     */
    public void setSelectionSetTime(long time) {
        selectionSetTime = time;
    }
}