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 com.locke.library.web.visitors.error; import java.io.Serializable; import org.apache.wicket.AttributeModifier; import org.apache.wicket.Component; import org.apache.wicket.Component.IVisitor; import org.apache.wicket.model.AbstractReadOnlyModel; public class ShowError implements IVisitor<Component>, Serializable { private static final long serialVersionUID = 7699039094418323127L; private final String errorCssClass; public ShowError(final String errorCssClass) { this.errorCssClass = errorCssClass; } public Object component(final Component component) { component.add(new AttributeModifier("class", true, new AbstractReadOnlyModel<String>() { private static final long serialVersionUID = 5439355914401726391L; @Override public String getObject() { return component.hasErrorMessage() ? errorCssClass : ""; } })); return CONTINUE_TRAVERSAL; } }