org.eclipse.jface.viewers.EditingSupport.java Source code

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Here is the source code for org.eclipse.jface.viewers.EditingSupport.java

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/*******************************************************************************
 * Copyright (c) 2006, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
 *                                         fix in bug 151295,167325,201905
 *******************************************************************************/

package org.eclipse.jface.viewers;

import org.eclipse.core.runtime.Assert;

/**
 * EditingSupport is the abstract superclass of the support for cell editing.
 *
 * @since 3.3
 *
 */
public abstract class EditingSupport {

    private ColumnViewer viewer;

    /**
     * @param viewer
     *            a new viewer
     */
    public EditingSupport(ColumnViewer viewer) {
        Assert.isNotNull(viewer, "Viewer is not allowed to be null"); //$NON-NLS-1$
        this.viewer = viewer;
    }

    /**
     * The editor to be shown
     *
     * @param element
     *            the model element
     * @return the CellEditor
     */
    protected abstract CellEditor getCellEditor(Object element);

    /**
     * Is the cell editable
     *
     * @param element
     *            the model element
     * @return true if editable
     */
    protected abstract boolean canEdit(Object element);

    /**
     * Get the value to set to the editor
     *
     * @param element
     *            the model element
     * @return the value shown
     */
    protected abstract Object getValue(Object element);

    /**
     * Sets the new value on the given element. Note that implementers need to
     * ensure that <code>getViewer().update(element, null)</code> or similar
     * methods are called, either directly or through some kind of listener
     * mechanism on the implementer's model, to cause the new value to appear in
     * the viewer.
     *
     * <p>
     * <b>Subclasses should overwrite.</b>
     * </p>
     *
     * @param element
     *            the model element
     * @param value
     *            the new value
     */
    protected abstract void setValue(Object element, Object value);

    /**
     * @return the viewer this editing support works for
     */
    public ColumnViewer getViewer() {
        return viewer;
    }

    /**
     * Initialize the editor. Frameworks like Databinding can hook in here and provide
     * a customized implementation. <p><b>Standard customers should not overwrite this method but {@link #getValue(Object)}</b></p>
     *
     * @param cellEditor
     *            the cell editor
     * @param cell
     *            the cell the editor is working for
     */
    protected void initializeCellEditorValue(CellEditor cellEditor, ViewerCell cell) {
        Object value = getValue(cell.getElement());
        cellEditor.setValue(value);
    }

    /**
     * Save the value of the cell editor back to the model. Frameworks like Databinding can hook in here and provide
     * a customized implementation. <p><b>Standard customers should not overwrite this method but {@link #setValue(Object, Object)} </b></p>
     * @param cellEditor
     *            the cell-editor
     * @param cell
     *            the cell the editor is working for
     */
    protected void saveCellEditorValue(CellEditor cellEditor, ViewerCell cell) {
        Object value = cellEditor.getValue();
        setValue(cell.getElement(), value);
    }

    boolean isLegacySupport() {
        return false;
    }
}