Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License 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 org.apache.wicket.markup.html.form; import org.apache.wicket.IRequestListener; import org.apache.wicket.markup.ComponentTag; import org.apache.wicket.markup.html.image.resource.LocalizedImageResource; import org.apache.wicket.model.IModel; import org.apache.wicket.model.Model; import org.apache.wicket.request.mapper.parameter.PageParameters; import org.apache.wicket.request.resource.IResource; import org.apache.wicket.request.resource.ResourceReference; /** * <input type="image"> component - like {@link Button} only with an image. * <p> * For details of how ImageButtons load, generate and manage images, see * {@link LocalizedImageResource}. * * @author Jonathan Locke */ public class ImageButton extends Button implements IRequestListener { private static final long serialVersionUID = 1L; /** The image resource this image component references */ private final LocalizedImageResource localizedImageResource = new LocalizedImageResource(this); /** * Constructs an image button from an image <code>ResourceReference</code>. That resource * reference will bind its resource to the current SharedResources. * * If you are using non sticky session clustering and the resource reference is pointing to a * <code>Resource</code> that isn't guaranteed to be on every server, for example a dynamic * image or resources that aren't added with a <code>IInitializer</code> at application startup. * Then if only that resource is requested from another server, without the rendering of the * page, the image won't be there and will result in a broken link. * * @param id * See Component * @param resourceReference * The shared image resource */ public ImageButton(final String id, final ResourceReference resourceReference) { this(id, resourceReference, null); } /** * Constructs an image button from an image <code>ResourceReference</code>. That resource * reference will bind its resource to the current SharedResources. * * If you are using non sticky session clustering and the resource reference is pointing to a * <code>Resource</code> that isn't guaranteed to be on every server, for example a dynamic * image or resources that aren't added with a <code>IInitializer</code> at application startup. * Then if only that resource is requested from another server, without the rendering of the * page, the image won't be there and will result in a broken link. * * @param id * See Component * @param resourceReference * The shared image resource * @param resourceParameters * The resource parameters */ public ImageButton(final String id, final ResourceReference resourceReference, PageParameters resourceParameters) { super(id); setImageResourceReference(resourceReference, resourceParameters); } /** * Constructs an image directly from an image resource. * * This one doesn't have the 'non sticky session clustering' problem that the * <code>ResourceReference</code> constructor has. But this will result in a non 'stable' url * and the url will have request parameters. * * @param id * See Component * * @param imageResource * The image resource */ public ImageButton(final String id, final IResource imageResource) { super(id); setImageResource(imageResource); } /** * @param id * @param model * @see org.apache.wicket.Component#Component(String, IModel) */ public ImageButton(final String id, final IModel<String> model) { super(id, model); } /** * @param id * See Component * @param string * Name of image * @see org.apache.wicket.Component#Component(String, IModel) */ public ImageButton(final String id, final String string) { this(id, new Model<String>(string)); } @Override public boolean rendersPage() { return false; } /** * @see org.apache.wicket.IResourceListener#onResourceRequested() */ @Override public void onRequest() { localizedImageResource.onResourceRequested(null); } /** * @param imageResource * The new ImageResource to set. */ public void setImageResource(final IResource imageResource) { localizedImageResource.setResource(imageResource); } /** * @param resourceReference * The shared ImageResource to set. */ public void setImageResourceReference(final ResourceReference resourceReference) { localizedImageResource.setResourceReference(resourceReference); } /** * @param resourceReference * The shared ImageResource to set. * @param parameters * Set the resource parameters for the resource. */ public void setImageResourceReference(final ResourceReference resourceReference, final PageParameters parameters) { localizedImageResource.setResourceReference(resourceReference, parameters); } /** * @see org.apache.wicket.Component#setDefaultModel(org.apache.wicket.model.IModel) */ @Override public ImageButton setDefaultModel(IModel<?> model) { // Null out the image resource, so we reload it (otherwise we'll be // stuck with the old model. localizedImageResource.setResourceReference(null); localizedImageResource.setResource(null); return (ImageButton) super.setDefaultModel(model); } /** * @return Resource returned from subclass */ protected IResource getImageResource() { return localizedImageResource.getResource(); } /** * @return ResourceReference returned from subclass */ protected ResourceReference getImageResourceReference() { return localizedImageResource.getResourceReference(); } /** * Processes the component tag. * * @param tag * Tag to modify * @see org.apache.wicket.Component#onComponentTag(ComponentTag) */ @Override protected final void onComponentTag(final ComponentTag tag) { checkComponentTag(tag, "input"); checkComponentTagAttribute(tag, "type", "image"); final IResource resource = getImageResource(); if (resource != null) { localizedImageResource.setResource(resource); } final ResourceReference resourceReference = getImageResourceReference(); if (resourceReference != null) { localizedImageResource.setResourceReference(resourceReference); } localizedImageResource.setSrcAttribute(tag); super.onComponentTag(tag); } /** * @see org.apache.wicket.markup.html.form.Button#getStatelessHint() */ @Override protected boolean getStatelessHint() { return getImageResource() == null && localizedImageResource.isStateless(); } }