celleditor.java

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/*******************************************************************************
 * Copyright (c) 2000, 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.viewers;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.util.Assert;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.jface.util.SafeRunnable;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * Abstract base class for cell editors. Implements property change listener handling,
 * and SWT window management.
 * <p>
 * Subclasses implement particular kinds of cell editors. This package contains various
 * specialized cell editors:
 * <ul>
 *   <li><code>TextCellEditor</code> - for simple text strings</li>
 *   <li><code>ColorCellEditor</code> - for colors</li>
 *   <li><code>ComboBoxCellEditor</code> - value selected from drop-down combo box</li>
 *   <li><code>CheckboxCellEditor</code> - boolean valued checkbox</li>
 *   <li><code>DialogCellEditor</code> - value from arbitrary dialog</li>
 * </ul>
 * </p>
 */
public abstract class CellEditor {

    /**
     * List of cell editor listeners (element type: <code>ICellEditorListener</code>).
     */
    private ListenerList listeners = new ListenerList();

    /**
     * List of cell editor property change listeners 
     * (element type: <code>IPropertyChangeListener</code>).
     */
    private ListenerList propertyChangeListeners = new ListenerList();

    /**
     * Indicates whether this cell editor's current value is valid.
     */
    private boolean valid = false;

    /**
     * Optional cell editor validator; <code>null</code> if none.
     */
    private ICellEditorValidator validator = null;

    /**
     * The error message string to display for invalid values;
     * <code>null</code> if none (that is, the value is valid).
     */
    private String errorMessage = null;

    /**
     * Indicates whether this cell editor has been changed recently.
     */
    private boolean dirty = false;

    /**
     * This cell editor's control, or <code>null</code>
     * if not created yet.
     */
    private Control control = null;

    /**
     * Default cell editor style
     */
    private static final int defaultStyle = SWT.NONE;

    /**
     * This cell editor's style
     */
    private int style = defaultStyle;

    /** 
     * Struct-like layout data for cell editors, with reasonable defaults
     * for all fields.
     */
    public static class LayoutData {
        /**
         * Horizontal alignment; <code>SWT.LEFT</code> by default.
         */
        public int horizontalAlignment = SWT.LEFT;

        /**
         * Indicates control grabs additional space; <code>true</code> by default.
         */
        public boolean grabHorizontal = true;

        /**
         * Minimum width in pixels; <code>50</code> pixels by default.
         */
        public int minimumWidth = 50;
    }

    /**
     * Property name for the copy action
     */
    public static final String COPY = "copy"; //$NON-NLS-1$

    /**
     * Property name for the cut action
     */
    public static final String CUT = "cut"; //$NON-NLS-1$

    /**
     * Property name for the delete action
     */
    public static final String DELETE = "delete"; //$NON-NLS-1$

    /**
     * Property name for the find action
     */
    public static final String FIND = "find"; //$NON-NLS-1$

    /**
     * Property name for the paste action
     */
    public static final String PASTE = "paste"; //$NON-NLS-1$

    /**
     * Property name for the redo action
     */
    public static final String REDO = "redo"; //$NON-NLS-1$

    /**
     * Property name for the select all action
     */
    public static final String SELECT_ALL = "selectall"; //$NON-NLS-1$

    /**
     * Property name for the undo action
     */
    public static final String UNDO = "undo"; //$NON-NLS-1$

    /**
     * Creates a new cell editor with no control 
     * The cell editor has no cell validator.
     * @since 2.1
     */
    protected CellEditor() {
    }

    /**
     * Creates a new cell editor under the given parent control.
     * The cell editor has no cell validator.
     *
     * @param parent the parent control
     */
    protected CellEditor(Composite parent) {
        this(parent, defaultStyle);
    }

    /**
     * Creates a new cell editor under the given parent control.
     * The cell editor has no cell validator.
     *
     * @param parent the parent control
     * @param style the style bits
     * @since 2.1
     */
    protected CellEditor(Composite parent, int style) {
        this.style = style;
        create(parent);
    }

    /**
     * Activates this cell editor.
     * <p>
     * The default implementation of this framework method
     * does nothing. Subclasses may reimplement.
     * </p>
     */
    public void activate() {
    }

    /**
     * Adds a listener to this cell editor.
     * Has no effect if an identical listener is already registered.
     *
     * @param listener a cell editor listener
     */
    public void addListener(ICellEditorListener listener) {
        listeners.add(listener);
    }

    /**
     * Adds a property change listener to this cell editor.
     * Has no effect if an identical property change listener 
     * is already registered.
     *
     * @param listener a property change listener
     */
    public void addPropertyChangeListener(IPropertyChangeListener listener) {
        propertyChangeListeners.add(listener);
    }

    /**
     * Creates the control for this cell editor under the given parent control.
     * <p>
     * This framework method must be implemented by concrete
     * subclasses.
     * </p>
     *
     * @param parent the parent control
     * @return the new control, or <code>null</code> if this cell editor has no control
     */
    protected abstract Control createControl(Composite parent);

    /**
     * Creates the control for this cell editor under the given parent control.
     * 
     * @param parent the parent control
     * @since 2.1
     */
    public void create(Composite parent) {
        Assert.isTrue(control == null);
        control = createControl(parent);
        // See 1GD5CA6: ITPUI:ALL - TaskView.setSelection does not work
        // Control is created with getVisible()==true by default.
        // This causes composite.setFocus() to work incorrectly.
        // The cell editor's control grabs focus instead, even if it is not active.
        // Make the control invisible here by default.
        deactivate();
    }

    /**
     * Hides this cell editor's control. Does nothing if this 
     * cell editor is not visible.
     */
    public void deactivate() {
        if (control != null && !control.isDisposed()) {
			control.setVisible(false);
		}
    }

    /**
     * Disposes of this cell editor and frees any associated SWT resources.
     */
    public void dispose() {
        if (control != null && !control.isDisposed()) {
            control.dispose();
        }
        control = null;
    }

    /**
     * Returns this cell editor's value.
     * <p>
     * This framework method must be implemented by concrete subclasses.
     * </p>
     *
     * @return the value of this cell editor
     * @see #getValue
     */
    protected abstract Object doGetValue();

    /**
     * Sets the focus to the cell editor's control.
     * <p>
     * This framework method must be implemented by concrete subclasses.
     * </p>
     *
     * @see #setFocus
     */
    protected abstract void doSetFocus();

    /**
     * Sets this cell editor's value.
     * <p>
     * This framework method must be implemented by concrete subclasses.
     * </p>
     *
     * @param value the value of this cell editor
     * @see #setValue
     */
    protected abstract void doSetValue(Object value);

    /**
     * Notifies all registered cell editor listeners of an apply event.
     * Only listeners registered at the time this method is called are notified.
     *
     * @see ICellEditorListener#applyEditorValue
     */
    protected void fireApplyEditorValue() {
        Object[] array = listeners.getListeners();
        for (int i = 0; i < array.length; i++) {
            final ICellEditorListener l = (ICellEditorListener) array[i];
            SafeRunnable.run(new SafeRunnable() {
                public void run() {
                    l.applyEditorValue();
                }
            });
        }
    }

    /**
     * Notifies all registered cell editor listeners that editing has been
     * canceled.
     *
     * @see ICellEditorListener#cancelEditor
     */
    protected void fireCancelEditor() {
        Object[] array = listeners.getListeners();
        for (int i = 0; i < array.length; i++) {
            final ICellEditorListener l = (ICellEditorListener) array[i];
            SafeRunnable.run(new SafeRunnable() {
                public void run() {
                    l.cancelEditor();
                }
            });
        }
    }

    /**
     * Notifies all registered cell editor listeners of a value change.
     *
     * @param oldValidState the valid state before the end user changed the value
     * @param newValidState the current valid state
     * @see ICellEditorListener#editorValueChanged
     */
    protected void fireEditorValueChanged(final boolean oldValidState,
            final boolean newValidState) {
        Object[] array = listeners.getListeners();
        for (int i = 0; i < array.length; i++) {
            final ICellEditorListener l = (ICellEditorListener) array[i];
            SafeRunnable.run(new SafeRunnable() {
                public void run() {
                    l.editorValueChanged(oldValidState, newValidState);
                }
            });
        }
    }

    /**
     * Notifies all registered property listeners
     * of an enablement change.
     *
     * @param actionId the id indicating what action's enablement has changed.
     */
    protected void fireEnablementChanged(final String actionId) {
        Object[] array = propertyChangeListeners.getListeners();
        for (int i = 0; i < array.length; i++) {
            final IPropertyChangeListener l = (IPropertyChangeListener) array[i];
            SafeRunnable.run(new SafeRunnable() {
                public void run() {
                    l.propertyChange(new PropertyChangeEvent(this, actionId,
                            null, null));
                }
            });
        }
    }

    /**
     * Sets the style bits for this cell editor.
     * 
     * @param style the SWT style bits for this cell editor
     * @since 2.1
     */
    public void setStyle(int style) {
        this.style = style;
    }

    /**
     * Returns the style bits for this cell editor.
     *
     * @return the style for this cell editor
     * @since 2.1
     */
    public int getStyle() {
        return style;
    }

    /**
     * Returns the control used to implement this cell editor.
     *
     * @return the control, or <code>null</code> if this cell editor has no control
     */
    public Control getControl() {
        return control;
    }

    /**
     * Returns the current error message for this cell editor.
     * 
     * @return the error message if the cell editor is in an invalid state,
     *  and <code>null</code> if the cell editor is valid
     */
    public String getErrorMessage() {
        return errorMessage;
    }

    /**
     * Returns a layout data object for this cell editor.
     * This is called each time the cell editor is activated
     * and controls the layout of the SWT table editor.
     * <p>
     * The default implementation of this method sets the 
     * minimum width to the control's preferred width.
     * Subclasses may extend or reimplement.
     * </p>
     *
     * @return the layout data object 
     */
    public LayoutData getLayoutData() {
        LayoutData result = new LayoutData();
        Control control = getControl();
        if (control != null) {
            result.minimumWidth = control.computeSize(SWT.DEFAULT, SWT.DEFAULT,
                    true).x;
        }
        return result;
    }