DialogCellEditor.java

/*******************************************************************************
 * Copyright (c) 2000, 2007 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.openlca.app.components;

import java.text.MessageFormat;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.FocusListener;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.ui.forms.events.HyperlinkAdapter;
import org.eclipse.ui.forms.events.HyperlinkEvent;
import org.eclipse.ui.forms.widgets.Hyperlink;
import org.openlca.app.M;
import org.openlca.app.util.Colors;

/**
 * An abstract cell editor that uses a dialog. Dialog cell editors usually have
 * a label control on the left and a button on the right. Pressing the button
 * opens a dialog window (for example, a color dialog or a file dialog) to
 * change the cell editor's value. The cell editor's value is the value of the
 * dialog.
 * <p>
 * Subclasses may override the following methods:
 * <ul>
 * <li><code>createButton</code>: creates the cell editor's button control</li>
 * <li><code>createContents</code>: creates the cell editor's 'display value'
 * control</li>
 * <li><code>updateContents</code>: updates the cell editor's 'display value'
 * control after its value has changed</li>
 * <li><code>openDialogBox</code>: opens the dialog box when the end user
 * presses the button</li>
 * </ul>
 * </p>
 */
public abstract class DialogCellEditor extends CellEditor {

	/**
	 * Image registry key for three dot image (value
	 * <code>"cell_editor_dots_button_image"</code>).
	 */
	public static final String CELL_EDITOR_IMG_DOTS_BUTTON = "cell_editor_dots_button_image";

	/**
	 * The editor control.
	 */
	private Composite editor;

	/**
	 * The current contents.
	 */
	private Control contents;

	/**
	 * The label that gets reused by <code>updateLabel</code>.
	 */
	private Label defaultLabel;

	/**
	 * The button.
	 */
	private Hyperlink hyperlink;

	/**
	 * Listens for 'focusLost' events and fires the 'apply' event as long as the
	 * focus wasn't lost because the dialog was opened.
	 */
	private FocusListener buttonFocusListener;

	/**
	 * The value of this cell editor; initially <code>null</code>.
	 */
	private Object value = null;

	static {
		ImageRegistry reg = JFaceResources.getImageRegistry();
		reg.put(CELL_EDITOR_IMG_DOTS_BUTTON, ImageDescriptor.createFromFile(
				DialogCellEditor.class, "images/dots_button.gif"));
	}

	/**
	 * Internal class for laying out the dialog.
	 */
	private class DialogCellLayout extends Layout {
		@Override
		public void layout(Composite editor, boolean force) {
			Rectangle bounds = editor.getClientArea();
			Point size = hyperlink.computeSize(SWT.DEFAULT, SWT.DEFAULT, force);
			if (contents != null) {
				contents.setBounds(0, 0, bounds.width - size.x, bounds.height);
			}
			hyperlink
					.setBounds(bounds.width - size.x, 0, size.x, bounds.height);
		}

		@Override
		public Point computeSize(Composite editor, int wHint, int hHint,
				boolean force) {
			if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT) {
				return new Point(wHint, hHint);
			}
			Point contentsSize = contents.computeSize(SWT.DEFAULT, SWT.DEFAULT,
					force);
			Point buttonSize = hyperlink.computeSize(SWT.DEFAULT, SWT.DEFAULT,
					force);
			// Just return the button width to ensure the button is not clipped
			// if the label is long.
			// The label will just use whatever extra width there is
			Point result = new Point(buttonSize.x, Math.max(contentsSize.y,
					buttonSize.y));
			return result;
		}
	}

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

	/**
	 * Creates a new dialog cell editor with no control
	 * 
	 * @since 2.1
	 */
	public DialogCellEditor() {
		setStyle(defaultStyle);
	}

	/**
	 * Creates a new dialog cell editor parented under the given control. The
	 * cell editor value is <code>null</code> initially, and has no validator.
	 * 
	 * @param parent
	 *            the parent control
	 */
	protected DialogCellEditor(Composite parent) {
		this(parent, defaultStyle);
	}

	/**
	 * Creates a new dialog cell editor parented under the given control. The
	 * cell editor value is <code>null</code> initially, and has no validator.
	 * 
	 * @param parent
	 *            the parent control
	 * @param style
	 *            the style bits
	 * @since 2.1
	 */
	protected DialogCellEditor(Composite parent, int style) {
		super(parent, style);
	}

	protected Hyperlink createLink(Composite parent) {
		Hyperlink link = new Hyperlink(parent, SWT.NONE);
		link.setText(M.Edit);
		link.setBackground(Colors.white());
		link.setForeground(Colors.linkBlue());
		return link;
	}

	/**
	 * Creates the controls used to show the value of this cell editor.
	 * <p>
	 * The default implementation of this framework method creates a label
	 * widget, using the same font and background color as the parent control.
	 * </p>
	 * <p>
	 * Subclasses may reimplement. If you reimplement this method, you should
	 * also reimplement <code>updateContents</code>.
	 * </p>
	 * 
	 * @param cell
	 *            the control for this cell editor
	 * @return the underlying control
	 */
	protected Control createContents(Composite cell) {
		defaultLabel = new Label(cell, SWT.LEFT);
		defaultLabel.setFont(cell.getFont());
		defaultLabel.setBackground(cell.getBackground());
		return defaultLabel;
	}

	/*
	 * (non-Javadoc) Method declared on CellEditor.
	 */
	@Override
	protected Control createControl(Composite parent) {

		Font font = parent.getFont();
		Color bg = parent.getBackground();

		editor = new Composite(parent, getStyle());
		editor.setFont(font);
		editor.setBackground(bg);
		editor.setLayout(new DialogCellLayout());

		contents = createContents(editor);
		updateContents(value);

		hyperlink = createLink(editor);
		hyperlink.setFont(font);

		hyperlink.addKeyListener(new KeyAdapter() {
			/*
			 * (non-Javadoc)
			 * 
			 * @see
			 * org.eclipse.swt.events.KeyListener#keyReleased(org.eclipse.swt
			 * .events.KeyEvent)
			 */
			@Override
			public void keyReleased(KeyEvent e) {
				if (e.character == '\u001b') { // Escape
					fireCancelEditor();
				}
			}
		});

		hyperlink.addFocusListener(getButtonFocusListener());

		hyperlink.addHyperlinkListener(new HyperlinkAdapter() {

			/*
			 * (non-Javadoc)
			 * 
			 * @see
			 * org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse
			 * .swt.events.SelectionEvent)
			 */
			@Override
			public void linkActivated(HyperlinkEvent e) {
				// Remove the button's focus listener since it's guaranteed
				// to lose focus when the dialog opens
				hyperlink.removeFocusListener(getButtonFocusListener());

				Object newValue = openDialogBox(editor);

				// Re-add the listener once the dialog closes
				hyperlink.addFocusListener(getButtonFocusListener());

				if (newValue != null) {
					boolean newValidState = isCorrect(newValue);
					if (newValidState) {
						markDirty();
						doSetValue(newValue);
					} else {
						// try to insert the current value into the error
						// message.
						setErrorMessage(MessageFormat.format(getErrorMessage(),
								new Object[] { newValue.toString() }));
					}
					fireApplyEditorValue();
				}
			}
		});

		setValueValid(true);

		return editor;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * Override in order to remove the button's focus listener if the celleditor
	 * is deactivating.
	 * 
	 * @see org.eclipse.jface.viewers.CellEditor#deactivate()
	 */
	@Override
	public void deactivate() {
		if (hyperlink != null && !hyperlink.isDisposed()) {
			hyperlink.removeFocusListener(getButtonFocusListener());
		}

		super.deactivate();
	}

	/*
	 * (non-Javadoc) Method declared on CellEditor.
	 */
	@Override
	protected Object doGetValue() {
		return value;
	}

	/*
	 * (non-Javadoc) Method declared on CellEditor. The focus is set to the cell
	 * editor's button.
	 */
	@Override
	protected void doSetFocus() {
		hyperlink.setFocus();

		// add a FocusListener to the button
		hyperlink.addFocusListener(getButtonFocusListener());
	}

	/**
	 * Return a listener for button focus.
	 * 
	 * @return FocusListener
	 */
	private FocusListener getButtonFocusListener() {
		if (buttonFocusListener == null) {
			buttonFocusListener = new FocusListener() {

				/*
				 * (non-Javadoc)
				 * 
				 * @see
				 * org.eclipse.swt.events.FocusListener#focusGained(org.eclipse
				 * .swt.events.FocusEvent)
				 */
				@Override
				public void focusGained(FocusEvent e) {
					// Do nothing
				}

				/*
				 * (non-Javadoc)
				 * 
				 * @see
				 * org.eclipse.swt.events.FocusListener#focusLost(org.eclipse
				 * .swt.events.FocusEvent)
				 */
				@Override
				public void focusLost(FocusEvent e) {
					DialogCellEditor.this.focusLost();
				}
			};
		}

		return buttonFocusListener;
	}

	/*
	 * (non-Javadoc) Method declared on CellEditor.
	 */
	@Override
	protected void doSetValue(Object value) {
		this.value = value;
		updateContents(value);
	}

	/**
	 * Returns the default label widget created by <code>createContents</code>.
	 * 
	 * @return the default label widget
	 */
	protected Label getDefaultLabel() {
		return defaultLabel;
	}

	/**
	 * Opens a dialog box under the given parent control and returns the
	 * dialog's value when it closes, or <code>null</code> if the dialog was
	 * canceled or no selection was made in the dialog.
	 * <p>
	 * This framework method must be implemented by concrete subclasses. It is
	 * called when the user has pressed the button and the dialog box must pop
	 * up.
	 * </p>
	 * 
	 * @param cellEditorWindow
	 *            the parent control cell editor's window so that a subclass can
	 *            adjust the dialog box accordingly
	 * @return the selected value, or <code>null</code> if the dialog was
	 *         canceled or no selection was made in the dialog
	 */
	protected abstract Object openDialogBox(Control cellEditorWindow);

	/**
	 * Updates the controls showing the value of this cell editor.
	 * <p>
	 * The default implementation of this framework method just converts the
	 * passed object to a string using <code>toString</code> and sets this as
	 * the text of the label widget.
	 * </p>
	 * <p>
	 * Subclasses may reimplement. If you reimplement this method, you should
	 * also reimplement <code>createContents</code>.
	 * </p>
	 * 
	 * @param value
	 *            the new value of this cell editor
	 */
	protected void updateContents(Object value) {
		if (defaultLabel == null) {
			return;
		}

		String text = "";
		if (value != null) {
			text = value.toString();
		}
		defaultLabel.setText(text);
	}
}