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 java.util.Collection; import org.apache.wicket.Component; import org.apache.wicket.IGenericComponent; import org.apache.wicket.WicketRuntimeException; import org.apache.wicket.markup.ComponentTag; import org.apache.wicket.markup.html.WebMarkupContainer; import org.apache.wicket.model.IModel; import org.apache.wicket.util.string.Strings; /** * Component representing a single checkbox choice in a * org.apache.wicket.markup.html.form.CheckGroup. * * Must be attached to an <input type="checkbox" ... > markup. * <p> * STATELESS NOTES: By default this component cannot be used inside a stateless form. If it is * desirable to use this inside a stateless form then * <ul> * <li> * override #getValue() and return some stateless value to uniquely identify this radio (eg relative * component path from group to this radio)</li> * <li> * override {@link #getStatelessHint()} and return <code>true</code></li> * </ul> * </p> * * @see org.apache.wicket.markup.html.form.CheckGroup * * @author Igor Vaynberg * * @param <T> * The model object type */ public class Check<T> extends LabeledWebMarkupContainer implements IGenericComponent<T, Check<T>> { private static final long serialVersionUID = 1L; private static final String ATTR_DISABLED = "disabled"; /** * page-scoped uuid of this check. this property must not be accessed directly, instead * {@link #getValue()} must be used */ private int uuid = -1; private final CheckGroup<T> group; /** * @see WebMarkupContainer#WebMarkupContainer(String) */ public Check(String id) { this(id, null, null); } /** * @param id * @param model * @see WebMarkupContainer#WebMarkupContainer(String, IModel) */ public Check(String id, IModel<T> model) { this(id, model, null); } /** * @param id * @param group * parent {@link CheckGroup} of this check * @see WebMarkupContainer#WebMarkupContainer(String) */ public Check(String id, CheckGroup<T> group) { this(id, null, group); } /** * @param id * @param model * @param group * parent {@link CheckGroup} of this check * @see WebMarkupContainer#WebMarkupContainer(String, IModel) */ public Check(String id, IModel<T> model, CheckGroup<T> group) { super(id, model); this.group = group; setOutputMarkupId(true); } /** * Form submission value used for the Html <code>value</code> attribute of the <code>input</code> tag. * <p> * If {@link Check}s are recreated on each render of their {@link CheckGroup}, this method should * be overridden to return a 'stable' value, otherwise its selection will be lost after a {@link Form} * was submitted and resulted in {@link Form#hasError()}. * * @return input value */ public String getValue() { if (uuid < 0) { uuid = getPage().getAutoIndex(); } return "check" + uuid; } @SuppressWarnings("unchecked") protected CheckGroup<T> getGroup() { CheckGroup<T> group = this.group; if (group == null) { group = findParent(CheckGroup.class); if (group == null) { throw new WicketRuntimeException( "Check component [" + getPath() + "] cannot find its parent CheckGroup"); } } return group; } /** * @see Component#onComponentTag(ComponentTag) * @param tag * the abstraction representing html tag of this component */ @Override protected void onComponentTag(final ComponentTag tag) { // Default handling for component tag super.onComponentTag(tag); // must be attached to <input type="checkbox" .../> tag checkComponentTag(tag, "input"); checkComponentTagAttribute(tag, "type", "checkbox"); CheckGroup<?> group = getGroup(); final String uuid = getValue(); // assign name and value tag.put("name", group.getInputName()); tag.put("value", uuid); // check if the model collection of the group contains the model object. // if it does check the check box. Collection<?> collection = (Collection<?>) group.getDefaultModelObject(); // check for npe in group's model object if (collection == null) { throw new WicketRuntimeException("CheckGroup [" + group.getPath() + "] contains a null model object, must be an object of type java.util.Collection"); } if (group.hasRawInput()) { final String raw = group.getRawInput(); if (!Strings.isEmpty(raw)) { final String[] values = raw.split(FormComponent.VALUE_SEPARATOR); for (String value : values) { if (uuid.equals(value)) { tag.put("checked", "checked"); } } } } else if (collection.contains(getDefaultModelObject())) { tag.put("checked", "checked"); } if (!isActionAuthorized(ENABLE) || !isEnabledInHierarchy() || !group.isEnabledInHierarchy()) { tag.put(ATTR_DISABLED, ATTR_DISABLED); } } /** * The value will be made available to the validator property by means of ${label}. It does not * have any specific meaning to Check itself. * * @param labelModel * @return this for chaining */ @Override public Check<T> setLabel(IModel<String> labelModel) { super.setLabel(labelModel); return this; } @Override protected boolean getStatelessHint() { // because this component uses uuid field it cannot be stateless return false; } }