Java tutorial
/* * Copyright 2010-2011 Amazon Technologies, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://aws.amazon.com/apache2.0 * * This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES * OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and * limitations under the License. */ package com.amazonaws.eclipse.core.ui.overview; import org.eclipse.jface.resource.ImageDescriptor; import org.eclipse.jface.resource.ImageRegistry; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Label; import org.eclipse.ui.forms.widgets.FormToolkit; import org.eclipse.ui.forms.widgets.TableWrapData; import com.amazonaws.eclipse.core.AwsToolkitCore; /** * Composite that uses gradients for the top and bottom borders. Subclasses are * expected to fill in the content through the header, main and footer * composites in this class. * <p> * This composite manages its own images so that they can be released as soon as * possible when this composite is disposed, so ensure that all instances are * properly disposed and that subclasses correctly call super.dispose() if they * override the dispose method. */ class GradientBoxComposite extends Composite { /** * Image registry so that any image resources are disposed of when this * object is disposed. Assumes only one GradientBoxComposite will be used, * so images aren't shared between multiple instances. */ private ImageRegistry imageRegistry = new ImageRegistry(); /** Form toolkit for creating the UI widgets */ private FormToolkit toolkit; /** The header composite, for subclasses to populate */ protected Composite headerComposite; /** The main composite, for subclasses to populate */ protected Composite mainComposite; /** The footer composite, for subclasses to populate */ protected Composite footerComposite; /** * Creates a new GradientBoxComposite widget within the specified parent and * using the specified form toolkit. * * @param parent * The composite to contain the new GradientBoxComposite. * @param toolkit * The form toolkit to use for creating the UI. */ public GradientBoxComposite(Composite parent, FormToolkit toolkit) { super(parent, SWT.NONE); this.toolkit = toolkit; initializeImageRegistry(); setLayout(LayoutUtils.newSlimTableWrapLayout(3)); createLabel("upper-left"); headerComposite = createHorizontalComposite("top"); createLabel("upper-right"); createVerticalComposite("left"); mainComposite = createHorizontalComposite(null); createVerticalComposite("right"); createLabel("lower-left"); footerComposite = createHorizontalComposite("bottom"); createLabel("lower-right"); } /* (non-Javadoc) * @see org.eclipse.swt.widgets.Widget#dispose() */ @Override public void dispose() { imageRegistry.dispose(); super.dispose(); } /* * Private Interface */ /** * Creates a new label with a specified image, and sizes the label so that * it is the same size as the image. * * @param imageKey * The key of the image to use in the new label. * @return The new label. */ private Label createLabel(String imageKey) { Image image = imageRegistry.get(imageKey); Label label = toolkit.createLabel(this, null); label.setImage(image); TableWrapData layoutData = new TableWrapData(TableWrapData.FILL); layoutData.heightHint = image.getImageData().height; layoutData.maxHeight = image.getImageData().height; layoutData.maxWidth = image.getImageData().width; label.setLayoutData(layoutData); return label; } /** * Creates a horizontal composite for this gradient box with the specified * background image tiled repeatedly in the horizontal direction. * * @param imageKey * The key of the image to use for the background. * @return The new composite. */ private Composite createHorizontalComposite(String imageKey) { Composite composite = toolkit.createComposite(this); TableWrapData layoutData = new TableWrapData(TableWrapData.FILL); if (imageKey != null) { composite.setBackgroundImage(imageRegistry.get(imageKey)); composite.setBackgroundMode(SWT.INHERIT_DEFAULT); layoutData.heightHint = imageRegistry.get(imageKey).getImageData().height; layoutData.maxWidth = imageRegistry.get(imageKey).getImageData().width; } composite.setLayoutData(layoutData); return composite; } /** * Creates a vertical composite for this gradient box with the specified * background image tiled repeatedly in the vertical direction. * * @param imageKey * The key of the image to use for the background. * @return The new composite. */ private Composite createVerticalComposite(String imageKey) { Composite composite = toolkit.createComposite(this); composite.setBackgroundImage(imageRegistry.get(imageKey)); composite.setBackgroundMode(SWT.INHERIT_DEFAULT); TableWrapData layoutData = new TableWrapData(TableWrapData.FILL, TableWrapData.FILL); layoutData.maxWidth = imageRegistry.get(imageKey).getImageData().width; layoutData.grabVertical = true; composite.setLayoutData(layoutData); return composite; } /** * Initializes the image resources used by this widget. */ private void initializeImageRegistry() { imageRegistry.put("upper-left", createImageDescriptor("icons/gradient-box/upper-left.png")); imageRegistry.put("top", createImageDescriptor("icons/gradient-box/top.png")); imageRegistry.put("upper-right", createImageDescriptor("icons/gradient-box/upper-right.png")); imageRegistry.put("left", createImageDescriptor("icons/gradient-box/left.png")); imageRegistry.put("right", createImageDescriptor("icons/gradient-box/right.png")); imageRegistry.put("lower-left", createImageDescriptor("icons/gradient-box/lower-left.png")); imageRegistry.put("bottom", createImageDescriptor("icons/gradient-box/bottom.png")); imageRegistry.put("lower-right", createImageDescriptor("icons/gradient-box/lower-right.png")); } /** * Creates an ImageDescriptor from this plugin for the specified path. * * @param imagePath * The path of the image to load. * @return The new image descriptor. */ private ImageDescriptor createImageDescriptor(String imagePath) { return ImageDescriptor.createFromURL(AwsToolkitCore.getDefault().getBundle().getEntry(imagePath)); } }