/*******************************************************************************
* Copyright (c) 2008 Oracle. 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:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.ui.internal.widgets;
import com.ibm.icu.text.Collator;
import java.util.Arrays;
import java.util.Comparator;
import org.eclipse.jface.viewers.ComboViewer;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jpt.ui.WidgetFactory;
import org.eclipse.jpt.ui.internal.JptUiMessages;
import org.eclipse.jpt.ui.internal.util.SWTUtil;
import org.eclipse.jpt.utility.model.Model;
import org.eclipse.jpt.utility.model.value.PropertyValueModel;
import org.eclipse.osgi.util.NLS;
import org.eclipse.swt.widgets.Composite;
/**
* This pane simply shows a combo where its data is populating through
* {@link #choices()} and a default value can also be added.
* <p>
* Here the layout of this pane:
* <pre>
* -----------------------------------------------------------------------------
* | ------------------------------------------------------------------------- |
* | | I |v| |
* | ------------------------------------------------------------------------- |
* -----------------------------------------------------------------------------</pre>
*
* @version 2.0
* @since 1.0
*/
@SuppressWarnings("nls")
abstract class EnumComboViewer<T extends Model, V> extends Pane<T>
{
/**
* The main widget of this pane.
*/
private ComboViewer comboViewer;
/**
* A constant used to represent the <code>null</code> value.
*/
public static final String NULL_VALUE = "null";
/**
* Creates a new <code>EnumComboViewer</code>.
*
* @param parentPane The parent container of this one
* @param parent The parent container
* @param widgetFactory The factory used to create various widgets
*/
EnumComboViewer(Pane<? extends T> parentPane,
Composite parent) {
super(parentPane, parent);
}
/**
* Creates a new <code>EnumComboViewer</code>.
*
* @param parentPane The parent container of this one
* @param parent The parent container
* @param widgetFactory The factory used to create various widgets
*/
EnumComboViewer(Pane<?> parentPane,
PropertyValueModel<? extends T> subjectHolder,
Composite parent) {
super(parentPane, subjectHolder, parent);
}
/**
* Creates a new <code>EnumComboViewer</code>.
*
* @param subjectHolder The holder of this pane's subject
* @param parent The parent container
* @param widgetFactory The factory used to create various widgets
*/
EnumComboViewer(PropertyValueModel<? extends T> subjectHolder,
Composite parent,
WidgetFactory widgetFactory) {
super(subjectHolder, parent, widgetFactory);
}
/**
* Creates the list of choices and add an extra element that represents the
* default value.
*
* @return The combo's choices including the default value
*/
private Object[] buildChoices() {
V[] choices = getChoices();
if (sortChoices()) {
Arrays.sort(choices, buildComparator());
}
Object[] extendedChoices = new Object[choices.length + 1];
System.arraycopy(choices, 0, extendedChoices, 1, choices.length);
extendedChoices[0] = NULL_VALUE;
return extendedChoices;
}
/**
* Return true to sort the choices in alphabetical order
* @return
*/
protected boolean sortChoices() {
return true;
}
/**
* Creates the <code>ComboViewer</code> with the right combo widgets.
*
* @param container The container of the combo
* @return A new <code>ComboViewer</code> containing the right combo widget
*/
abstract ComboViewer addComboViewer(Composite container);
private Comparator<Object> buildComparator() {
return new Comparator<Object>() {
final LabelProvider labelProvider = buildLabelProvider();
public int compare(Object value1, Object value2) {
String displayString1 = labelProvider.getText(value1);
String displayString2 = labelProvider.getText(value2);
return Collator.getInstance().compare(displayString1, displayString2);
}
};
}
/**
* Retrieves the localized string from the given NLS class by creating the
* key. That key is the concatenation of the composite's short class name
* with the toString() of the given value separated by an underscore.
*
* @param nlsClass The NLS class used to retrieve the localized text
* @param compositeClass The class used for creating the key, its short class
* name is the beginning of the key
* @param value The value used to append its toString() to the generated key
* @return The localized text associated with the value
*/
protected final String buildDisplayString(Class<?> nlsClass,
Class<?> compositeClass,
Object value) {
return SWTUtil.buildDisplayString(nlsClass, compositeClass, value);
}
/**
* Retrieves the localized string from the given NLS class by creating the
* key. That key is the concatenation of the composite's short class name
* with the toString() of the given value separated by an underscore.
*
* @param nlsClass The NLS class used to retrieve the localized text
* @param composite The object used to retrieve the short class name that is
* the beginning of the key
* @param value The value used to append its toString() to the generated key
* @return The localized text associated with the value
*/
protected final String buildDisplayString(Class<?> nlsClass,
Object composite,
Object value) {
return SWTUtil.buildDisplayString(nlsClass, composite, value);
}
/**
* Creates the display string for the given element. If the element is the
* virtual <code>null</code> value then its display string will be "Default"
* appended by the actual default value, if it exists.
*
* @param value The value to convert into a human readable string
* @return The string representation of the given element
*/
@SuppressWarnings("unchecked")
private String buildDisplayString(Object value) {
if (value == NULL_VALUE) {
V defaultValue = (getSubject() != null) ? getDefaultValue() : null;
if (defaultValue != null) {
String displayString = displayString(defaultValue);
return NLS.bind(JptUiMessages.EnumComboViewer_defaultWithDefault, displayString);
}
return nullDisplayString();
}
return displayString((V) value);
}
final LabelProvider buildLabelProvider() {
return new LabelProvider() {
@Override
public String getText(Object element) {
return buildDisplayString(element);
}
};
}
private ISelection buildSelection() {
Object value = (getSubject() != null) ? getValue() : null;
if (value == null) {
value = NULL_VALUE;
}
return new StructuredSelection(value);
}
private ISelectionChangedListener buildSelectionChangedListener() {
return new ISelectionChangedListener() {
public void selectionChanged(SelectionChangedEvent e) {
if (!isPopulating()) {
StructuredSelection selection = (StructuredSelection) e.getSelection();
valueChanged(selection.getFirstElement());
}
}
};
}
/**
* Returns the possible choices to show in the viewer.
*
* @return The items to show in the combos
*/
protected abstract V[] getChoices();
/**
* Returns the default value, this method is not called if the subject is
* <code>null</code>.
*
* @return The value that is declared as being the default when it is not
* defined or <code>null</code> if there is no default value
*/
protected abstract V getDefaultValue();
/**
* Returns the displayable string for the given value.
*
* @param value The value to translate into a human readable string
* @return The localized text representing the given value
*/
protected abstract String displayString(V value);
/**
* Returns the displayable string for a null value.
*/
protected String nullDisplayString() {
return null; //I would rather display nothing than "Default()"
}
/*
* (non-Javadoc)
*/
@Override
protected void doPopulate() {
super.doPopulate();
this.populateCombo();
}
/**
* Returns
*
* @return
*/
final ComboViewer getComboViewer() {
return comboViewer;
}
/**
* Retrieves the subject's value. The subject is never <code>null</code>.
*
* @return The subject' value, which can be <code>null</code>
*/
protected abstract V getValue();
/*
* (non-Javadoc)
*/
@Override
protected final void initializeLayout(Composite container) {
this.comboViewer = this.addComboViewer(container);
this.comboViewer.addSelectionChangedListener(buildSelectionChangedListener());
}
/**
* Populates the combo by re-adding all the items.
*/
private void populateCombo() {
removeAll();
comboViewer.add(buildChoices());
updateSelection();
}
/*
* (non-Javadoc)
*/
@Override
protected void propertyChanged(String propertyName) {
super.propertyChanged(propertyName);
this.populateCombo();
}
/**
* Removes all the items from the combo.
*/
abstract void removeAll();
/**
* Requests the given new value be set on the subject.
*
* @param value The new value to be set
*/
protected abstract void setValue(V value);
/**
* Updates the cursor, which is required to show the entire selected item
* within the combo's area.
*/
abstract void updateCursor();
/**
* Updates the combo's selected item.
*/
private void updateSelection() {
comboViewer.setSelection(buildSelection());
updateCursor();
}
/**
* The selection changes, notify the subclass to set the value.
*
* @param value The new selected item
*/
@SuppressWarnings("unchecked")
private void valueChanged(Object value) {
// Convert the default "null" value to a real null
if (value == NULL_VALUE) {
value = null;
}
setPopulating(true);
try {
setValue((V) value);
}
finally {
setPopulating(false);
}
}
}
