org.eclipse.jface.preference.PreferenceNode Maven / Gradle / Ivy
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/*******************************************************************************
* Copyright (c) 2000, 2018 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
*******************************************************************************/
package org.eclipse.jface.preference;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
/**
* A concrete implementation of a node in a preference dialog tree. This class
* also supports lazy creation of the node's preference page.
*/
public class PreferenceNode implements IPreferenceNode {
/**
* Preference page, or null if not yet loaded.
*/
private IPreferencePage page;
/**
* The list of subnodes (immediate children) of this node (element type:
* IPreferenceNode).
*/
private List subNodes;
/**
* Name of a class that implements IPreferencePage, or
* null if none.
*/
private String classname;
/**
* The id of this node.
*/
private String id;
/**
* Text label for this node. Note that this field is only used prior to the
* creation of the preference page.
*/
private String label;
/**
* Image descriptor for this node, or null if none.
*/
private ImageDescriptor imageDescriptor;
/**
* Cached image, or null if none.
*/
private Image image;
/**
* Creates a new preference node with the given id. The new node has no
* subnodes.
*
* @param id
* the node id
*/
public PreferenceNode(String id) {
Assert.isNotNull(id);
this.id = id;
}
/**
* Creates a preference node with the given id, label, and image, and
* lazily-loaded preference page. The preference node assumes (sole)
* responsibility for disposing of the image; this will happen when the node
* is disposed.
*
* @param id
* the node id
* @param label
* the label used to display the node in the preference dialog's
* tree
* @param image
* the image displayed left of the label in the preference
* dialog's tree, or null if none
* @param className
* the class name of the preference page; this class must
* implement IPreferencePage
*/
public PreferenceNode(String id, String label, ImageDescriptor image,
String className) {
this(id);
this.imageDescriptor = image;
Assert.isNotNull(label);
this.label = label;
this.classname = className;
}
/**
* Creates a preference node with the given id and preference page. The
* title of the preference page is used for the node label. The node will
* not have an image.
*
* @param id
* the node id
* @param preferencePage
* the preference page
*/
public PreferenceNode(String id, IPreferencePage preferencePage) {
this(id);
Assert.isNotNull(preferencePage);
page = preferencePage;
}
@Override
public void add(IPreferenceNode node) {
if (subNodes == null) {
subNodes = new ArrayList<>();
}
subNodes.add(node);
}
/**
* Creates a new instance of the given class className.
*
* @return new Object or null in case of failures.
*/
private Object createObject(String className) {
Assert.isNotNull(className);
try {
Class cl = Class.forName(className);
return cl.getDeclaredConstructor().newInstance();
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | NoSuchMethodError
| IllegalArgumentException | InvocationTargetException | NoSuchMethodException | SecurityException e) {
return null;
}
}
@Override
public void createPage() {
page = (IPreferencePage) createObject(classname);
if (getLabelImage() != null) {
page.setImageDescriptor(imageDescriptor);
}
page.setTitle(label);
}
@Override
public void disposeResources() {
if (image != null) {
image.dispose();
image = null;
}
if (page != null) {
page.dispose();
page = null;
}
}
@Override
public IPreferenceNode findSubNode(String id) {
Assert.isNotNull(id);
Assert.isTrue(id.length() > 0);
if (subNodes == null) {
return null;
}
int size = subNodes.size();
for (int i = 0; i < size; i++) {
IPreferenceNode node = subNodes.get(i);
if (id.equals(node.getId())) {
return node;
}
}
return null;
}
@Override
public String getId() {
return this.id;
}
/**
* Returns the image descriptor for this node.
*
* @return the image descriptor
*/
protected ImageDescriptor getImageDescriptor() {
return imageDescriptor;
}
@Override
public Image getLabelImage() {
if (image == null && imageDescriptor != null) {
image = imageDescriptor.createImage();
}
return image;
}
@Override
public String getLabelText() {
if (page != null) {
return page.getTitle();
}
return label;
}
@Override
public IPreferencePage getPage() {
return page;
}
@Override
public IPreferenceNode[] getSubNodes() {
if (subNodes == null) {
return new IPreferenceNode[0];
}
return subNodes
.toArray(new IPreferenceNode[subNodes.size()]);
}
@Override
public IPreferenceNode remove(String id) {
IPreferenceNode node = findSubNode(id);
if (node != null) {
remove(node);
}
return node;
}
@Override
public boolean remove(IPreferenceNode node) {
if (subNodes == null) {
return false;
}
return subNodes.remove(node);
}
/**
* Set the current page to be newPage.
*
* @param newPage page to set
*/
public void setPage(IPreferencePage newPage) {
page = newPage;
}
}