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.ajax.form; import java.util.Locale; import org.apache.wicket.Application; import org.apache.wicket.Component; import org.apache.wicket.WicketRuntimeException; import org.apache.wicket.ajax.AjaxEventBehavior; import org.apache.wicket.ajax.AjaxRequestTarget; import org.apache.wicket.ajax.attributes.AjaxRequestAttributes; import org.apache.wicket.ajax.attributes.AjaxRequestAttributes.Method; import org.apache.wicket.markup.html.form.FormComponent; import org.apache.wicket.markup.html.form.validation.IFormValidator; import org.apache.wicket.util.lang.Args; import org.danekja.java.util.function.serializable.SerializableConsumer; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * A behavior that updates the hosting FormComponent via ajax when an event it is attached to is * triggered. This behavior encapsulates the entire form-processing workflow as relevant only to * this component so if validation is successful the component's model will be updated according to * the submitted value. * <p> * NOTE: This behavior does not validate any {@link IFormValidator}s attached to this form even * though they may reference the component being updated. * <p> * NOTE: This behavior does not work on Choices or Groups use the * {@link AjaxFormChoiceComponentUpdatingBehavior} for that. * * @since 1.2 * * @author Igor Vaynberg (ivaynberg) * @see #onUpdate(org.apache.wicket.ajax.AjaxRequestTarget) * @see #onError(org.apache.wicket.ajax.AjaxRequestTarget, RuntimeException) */ public abstract class AjaxFormComponentUpdatingBehavior extends AjaxEventBehavior { private static final Logger log = LoggerFactory.getLogger(AjaxFormComponentUpdatingBehavior.class); /** * */ private static final long serialVersionUID = 1L; /** * Construct. * * @param event * event to trigger this behavior */ public AjaxFormComponentUpdatingBehavior(final String event) { super(event); } /** * * @see org.apache.wicket.behavior.AbstractAjaxBehavior#onBind() */ @Override protected void onBind() { super.onBind(); Component component = getComponent(); if (!(component instanceof FormComponent)) { throw new WicketRuntimeException( "Behavior " + getClass().getName() + " can only be added to an instance of a FormComponent"); } checkComponent((FormComponent<?>) component); } /** * Check the component this behavior is bound to. * <p> * Logs a warning in development mode when an {@link AjaxFormChoiceComponentUpdatingBehavior} * should be used. * * @param component * bound component */ protected void checkComponent(FormComponent<?> component) { if (Application.get().usesDevelopmentConfig() && AjaxFormChoiceComponentUpdatingBehavior.appliesTo(component)) { log.warn(String.format( "AjaxFormComponentUpdatingBehavior is not supposed to be added in the form component at path: \"%s\". " + "Use the AjaxFormChoiceComponentUpdatingBehavior instead, that is meant for choices/groups that are not one component in the html but many", component.getPageRelativePath())); } } /** * * @return FormComponent */ protected final FormComponent<?> getFormComponent() { return (FormComponent<?>) getComponent(); } @Override protected void updateAjaxAttributes(AjaxRequestAttributes attributes) { super.updateAjaxAttributes(attributes); attributes.setMethod(Method.POST); } /** * * @see org.apache.wicket.ajax.AjaxEventBehavior#onEvent(org.apache.wicket.ajax.AjaxRequestTarget) */ @Override protected final void onEvent(final AjaxRequestTarget target) { final FormComponent<?> formComponent = getFormComponent(); if ("blur".equals(getEvent().toLowerCase(Locale.ROOT)) && disableFocusOnBlur()) { target.focusComponent(null); } try { formComponent.inputChanged(); formComponent.validate(); if (formComponent.isValid()) { if (getUpdateModel()) { formComponent.valid(); formComponent.updateModel(); } onUpdate(target); } else { formComponent.invalid(); onError(target, null); } } catch (RuntimeException e) { onError(target, e); } formComponent.updateAutoLabels(target); } /** * Gives the control to the application to decide whether the form component model should * be updated automatically or not. Make sure to call {@link org.apache.wicket.markup.html.form.FormComponent#valid()} * additionally in case the application want to update the model manually. * * @return true if the model of form component should be updated, false otherwise */ protected boolean getUpdateModel() { return true; } /** * Determines whether the focus will not be restored when the event is blur. By default this is * true, as we don't want to re-focus component on blur event. * * @return <code>true</code> if refocusing should be disabled, <code>false</code> otherwise */ protected boolean disableFocusOnBlur() { return true; } /** * Listener invoked on the ajax request. This listener is invoked after the component's model * has been updated. * <p> * Note: {@link #onError(AjaxRequestTarget, RuntimeException)} is called instead when processing * of the {@link FormComponent} failed with conversion or validation errors! * * @param target * the current request handler */ protected abstract void onUpdate(AjaxRequestTarget target); /** * Called to handle any error resulting from updating form component. Errors thrown from * {@link #onUpdate(org.apache.wicket.ajax.AjaxRequestTarget)} will not be caught here. * * The RuntimeException will be null if it was just a validation or conversion error of the * FormComponent * * @param target * the current request handler * @param e * the error that occurred during the update of the component */ protected void onError(AjaxRequestTarget target, RuntimeException e) { if (e != null) { throw e; } } /** * Creates an {@link AjaxFormComponentUpdatingBehavior} based on lambda expressions * * @param eventName * the event name * @param onUpdate * the {@code SerializableConsumer} which accepts the {@link AjaxRequestTarget} * @return the {@link AjaxFormComponentUpdatingBehavior} */ public static AjaxFormComponentUpdatingBehavior onUpdate(String eventName, SerializableConsumer<AjaxRequestTarget> onUpdate) { Args.notNull(onUpdate, "onUpdate"); return new AjaxFormComponentUpdatingBehavior(eventName) { private static final long serialVersionUID = 1L; @Override protected void onUpdate(AjaxRequestTarget target) { onUpdate.accept(target); } }; } }