/*******************************************************************************
* Copyright (c) 2000, 2008 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.preference;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.core.runtime.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;
/**
* An abstract field editor that manages a list of input values.
* The editor displays a list containing the values, buttons for
* adding and removing values, and Up and Down buttons to adjust
* the order of elements in the list.
* <p>
* Subclasses must implement the <code>parseString</code>,
* <code>createList</code>, and <code>getNewInputObject</code>
* framework methods.
* </p>
*/
public abstract class ListEditor extends FieldEditor {
/**
* The list widget; <code>null</code> if none
* (before creation or after disposal).
*/
private List list;
/**
* The button box containing the Add, Remove, Up, and Down buttons;
* <code>null</code> if none (before creation or after disposal).
*/
private Composite buttonBox;
/**
* The Add button.
*/
private Button addButton;
/**
* The Remove button.
*/
private Button removeButton;
/**
* The Up button.
*/
private Button upButton;
/**
* The Down button.
*/
private Button downButton;
/**
* The selection listener.
*/
private SelectionListener selectionListener;
/**
* Creates a new list field editor
*/
protected ListEditor() {
}
/**
* Creates a list field editor.
*
* @param name the name of the preference this field editor works on
* @param labelText the label text of the field editor
* @param parent the parent of the field editor's control
*/
protected ListEditor(String name, String labelText, Composite parent) {
init(name, labelText);
createControl(parent);
}
/**
* Notifies that the Add button has been pressed.
*/
private void addPressed() {
setPresentsDefaultValue(false);
String input = getNewInputObject();
if (input != null) {
int index = list.getSelectionIndex();
if (index >= 0) {
list.add(input, index + 1);
} else {
list.add(input, 0);
}
selectionChanged();
}
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
protected void adjustForNumColumns(int numColumns) {
Control control = getLabelControl();
((GridData) control.getLayoutData()).horizontalSpan = numColumns;
((GridData) list.getLayoutData()).horizontalSpan = numColumns - 1;
}
/**
* Creates the Add, Remove, Up, and Down button in the given button box.
*
* @param box the box for the buttons
*/
private void createButtons(Composite box) {
addButton = createPushButton(box, "ListEditor.add");//$NON-NLS-1$
removeButton = createPushButton(box, "ListEditor.remove");//$NON-NLS-1$
upButton = createPushButton(box, "ListEditor.up");//$NON-NLS-1$
downButton = createPushButton(box, "ListEditor.down");//$NON-NLS-1$
}
/**
* Combines the given list of items into a single string.
* This method is the converse of <code>parseString</code>.
* <p>
* Subclasses must implement this method.
* </p>
*
* @param items the list of items
* @return the combined string
* @see #parseString
*/
protected abstract String createList(String[] items);
/**
* Helper method to create a push button.
*
* @param parent the parent control
* @param key the resource name used to supply the button's label text
* @return Button
*/
private Button createPushButton(Composite parent, String key) {
Button button = new Button(parent, SWT.PUSH);
button.setText(JFaceResources.getString(key));
button.setFont(parent.getFont());
GridData data = new GridData(GridData.FILL_HORIZONTAL);
int widthHint = convertHorizontalDLUsToPixels(button,
IDialogConstants.BUTTON_WIDTH);
data.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT,
SWT.DEFAULT, true).x);
button.setLayoutData(data);
button.addSelectionListener(getSelectionListener());
return button;
}
/**
* Creates a selection listener.
*/
public void createSelectionListener() {
selectionListener = new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
Widget widget = event.widget;
if (widget == addButton) {
addPressed();
} else if (widget == removeButton) {
removePressed();
} else if (widget == upButton) {
upPressed();
} else if (widget == downButton) {
downPressed();
} else if (widget == list) {
selectionChanged();
}
}
};
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
protected void doFillIntoGrid(Composite parent, int numColumns) {
Control control = getLabelControl(parent);
GridData gd = new GridData();
gd.horizontalSpan = numColumns;
control.setLayoutData(gd);
list = getListControl(parent);
gd = new GridData(GridData.FILL_HORIZONTAL);
gd.verticalAlignment = GridData.FILL;
gd.horizontalSpan = numColumns - 1;
gd.grabExcessHorizontalSpace = true;
list.setLayoutData(gd);
buttonBox = getButtonBoxControl(parent);
gd = new GridData();
gd.verticalAlignment = GridData.BEGINNING;
buttonBox.setLayoutData(gd);
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
protected void doLoad() {
if (list != null) {
String s = getPreferenceStore().getString(getPreferenceName());
String[] array = parseString(s);
for (int i = 0; i < array.length; i++) {
list.add(array[i]);
}
}
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
protected void doLoadDefault() {
if (list != null) {
list.removeAll();
String s = getPreferenceStore().getDefaultString(
getPreferenceName());
String[] array = parseString(s);
for (int i = 0; i < array.length; i++) {
list.add(array[i]);
}
}
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
protected void doStore() {
String s = createList(list.getItems());
if (s != null) {
getPreferenceStore().setValue(getPreferenceName(), s);
}
}
/**
* Notifies that the Down button has been pressed.
*/
private void downPressed() {
swap(false);
}
/**
* Returns this field editor's button box containing the Add, Remove,
* Up, and Down button.
*
* @param parent the parent control
* @return the button box
*/
public Composite getButtonBoxControl(Composite parent) {
if (buttonBox == null) {
buttonBox = new Composite(parent, SWT.NULL);
GridLayout layout = new GridLayout();
layout.marginWidth = 0;
buttonBox.setLayout(layout);
createButtons(buttonBox);
buttonBox.addDisposeListener(new DisposeListener() {
public void widgetDisposed(DisposeEvent event) {
addButton = null;
removeButton = null;
upButton = null;
downButton = null;
buttonBox = null;
}
});
} else {
checkParent(buttonBox, parent);
}
selectionChanged();
return buttonBox;
}
/**
* Returns this field editor's list control.
*
* @param parent the parent control
* @return the list control
*/
public List getListControl(Composite parent) {
if (list == null) {
list = new List(parent, SWT.BORDER | SWT.SINGLE | SWT.V_SCROLL
| SWT.H_SCROLL);
list.setFont(parent.getFont());
list.addSelectionListener(getSelectionListener());
list.addDisposeListener(new DisposeListener() {
public void widgetDisposed(DisposeEvent event) {
list = null;
}
});
} else {
checkParent(list, parent);
}
return list;
}
/**
* Creates and returns a new item for the list.
* <p>
* Subclasses must implement this method.
* </p>
*
* @return a new item
*/
protected abstract String getNewInputObject();
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
public int getNumberOfControls() {
return 2;
}
/**
* Returns this field editor's selection listener.
* The listener is created if nessessary.
*
* @return the selection listener
*/
private SelectionListener getSelectionListener() {
if (selectionListener == null) {
createSelectionListener();
}
return selectionListener;
}
/**
* Returns this field editor's shell.
* <p>
* This method is internal to the framework; subclassers should not call
* this method.
* </p>
*
* @return the shell
*/
protected Shell getShell() {
if (addButton == null) {
return null;
}
return addButton.getShell();
}
/**
* Splits the given string into a list of strings.
* This method is the converse of <code>createList</code>.
* <p>
* Subclasses must implement this method.
* </p>
*
* @param stringList the string
* @return an array of <code>String</code>
* @see #createList
*/
protected abstract String[] parseString(String stringList);
/**
* Notifies that the Remove button has been pressed.
*/
private void removePressed() {
setPresentsDefaultValue(false);
int index = list.getSelectionIndex();
if (index >= 0) {
list.remove(index);
selectionChanged();
}
}
/**
* Invoked when the selection in the list has changed.
*
* <p>
* The default implementation of this method utilizes the selection index
* and the size of the list to toggle the enablement of the up, down and
* remove buttons.
* </p>
*
* <p>
* Sublcasses may override.
* </p>
*
* @since 3.5
*/
protected void selectionChanged() {
int index = list.getSelectionIndex();
int size = list.getItemCount();
removeButton.setEnabled(index >= 0);
upButton.setEnabled(size > 1 && index > 0);
downButton.setEnabled(size > 1 && index >= 0 && index < size - 1);
}
/* (non-Javadoc)
* Method declared on FieldEditor.
*/
public void setFocus() {
if (list != null) {
list.setFocus();
}
}
/**
* Moves the currently selected item up or down.
*
* @param up <code>true</code> if the item should move up,
* and <code>false</code> if it should move down
*/
private void swap(boolean up) {
setPresentsDefaultValue(false);
int index = list.getSelectionIndex();
int target = up ? index - 1 : index + 1;
if (index >= 0) {
String[] selection = list.getSelection();
Assert.isTrue(selection.length == 1);
list.remove(index);
list.add(selection[0], target);
list.setSelection(target);
}
selectionChanged();
}
/**
* Notifies that the Up button has been pressed.
*/
private void upPressed() {
swap(true);
}
/*
* @see FieldEditor.setEnabled(boolean,Composite).
*/
public void setEnabled(boolean enabled, Composite parent) {
super.setEnabled(enabled, parent);
getListControl(parent).setEnabled(enabled);
addButton.setEnabled(enabled);
removeButton.setEnabled(enabled);
upButton.setEnabled(enabled);
downButton.setEnabled(enabled);
}
/**
* Return the Add button.
*
* @return the button
* @since 3.5
*/
protected Button getAddButton() {
return addButton;
}
/**
* Return the Remove button.
*
* @return the button
* @since 3.5
*/
protected Button getRemoveButton() {
return removeButton;
}
/**
* Return the Up button.
*
* @return the button
* @since 3.5
*/
protected Button getUpButton() {
return upButton;
}
/**
* Return the Down button.
*
* @return the button
* @since 3.5
*/
protected Button getDownButton() {
return downButton;
}
/**
* Return the List.
*
* @return the list
* @since 3.5
*/
protected List getList() {
return list;
}
}