Java tutorial
/* * $Id$ * * 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.struts2.components; import com.opensymphony.xwork2.util.ValueStack; import org.apache.commons.lang3.StringUtils; import org.apache.struts2.util.ContainUtil; import org.apache.struts2.util.MakeIterator; import org.apache.struts2.views.annotations.StrutsTagAttribute; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.lang.reflect.Array; import java.util.Collection; import java.util.Map; /** * <p> * DoubleListUIBean is the standard superclass of all Struts list handling components. * </p> * * * <!-- START SNIPPET: javadoc --> * <p> * Note that the listkey and listvalue attribute will default to "key" and "value" * respectively only when the list attribute is evaluated to a Map or its descendant. * Everything else will result in listkey and listvalue to be null and not used. * </p> * <!-- END SNIPPET: javadoc --> */ public abstract class ListUIBean extends UIBean { protected Object list; protected String listKey; protected String listValueKey; protected String listValue; protected String listLabelKey; protected String listCssClass; protected String listCssStyle; protected String listTitle; // indicate if an exception is to be thrown when value attribute is null protected boolean throwExceptionOnNullValueAttribute = false; protected ListUIBean(ValueStack stack, HttpServletRequest request, HttpServletResponse response) { super(stack, request, response); } public void evaluateExtraParams() { Object value = null; if (list == null) { list = parameters.get("list"); } if (list instanceof String) { value = findValue((String) list); } else if (list instanceof Collection) { value = list; } else if (MakeIterator.isIterable(list)) { value = MakeIterator.convert(list); } if (value == null) { if (throwExceptionOnNullValueAttribute) { // will throw an exception if not found value = findValue((list == null) ? (String) list : list.toString(), "list", "The requested list key '" + list + "' could not be resolved as a collection/array/map/enumeration/iterator type. " + "Example: people or people.{name}"); } else { // ww-1010, allows value with null value to be compatible with ww // 2.1.7 behaviour value = findValue((list == null) ? (String) list : list.toString()); } } if (value instanceof Collection) { addParameter("list", value); } else { addParameter("list", MakeIterator.convert(value)); } if (value instanceof Collection) { addParameter("listSize", ((Collection) value).size()); } else if (value instanceof Map) { addParameter("listSize", ((Map) value).size()); } else if (value != null && value.getClass().isArray()) { addParameter("listSize", Array.getLength(value)); } if (listKey != null) { listKey = stripExpressionIfAltSyntax(listKey); addParameter("listKey", listKey); } else if (value instanceof Map) { addParameter("listKey", "key"); } if (listValueKey != null) { listValueKey = stripExpressionIfAltSyntax(listValueKey); addParameter("listValueKey", listValueKey); } if (listValue != null) { listValue = stripExpressionIfAltSyntax(listValue); addParameter("listValue", listValue); } else if (value instanceof Map) { addParameter("listValue", "value"); } if (listLabelKey != null) { listLabelKey = stripExpressionIfAltSyntax(listLabelKey); addParameter("listLabelKey", listLabelKey); } if (StringUtils.isNotBlank(listCssClass)) { addParameter("listCssClass", listCssClass); } if (StringUtils.isNotBlank(listCssStyle)) { addParameter("listCssStyle", listCssStyle); } if (StringUtils.isNotBlank(listTitle)) { addParameter("listTitle", listTitle); } } public boolean contains(Object obj1, Object obj2) { return ContainUtil.contains(obj1, obj2); } protected Class getValueClassType() { return null; // don't convert nameValue to anything, we need the raw value } @StrutsTagAttribute(description = "Iterable source to populate from. If the list is a Map (key, value), the Map key will become the option 'value'" + " parameter and the Map value will become the option body.", required = true) public void setList(Object list) { this.list = list; } @StrutsTagAttribute(description = "Property of list objects to get field value from") public void setListKey(String listKey) { this.listKey = listKey; } @StrutsTagAttribute(description = "Property of list objects to get field value label from") public void setListValueKey(String listValueKey) { this.listValueKey = listValueKey; } @StrutsTagAttribute(description = "Property of list objects to get field content from") public void setListValue(String listValue) { this.listValue = listValue; } @StrutsTagAttribute(description = "Property of list objects to be used to lookup for localised version of field label") public void setListLabelKey(String listLabelKey) { this.listLabelKey = listLabelKey; } @StrutsTagAttribute(description = "Property of list objects to get css class from") public void setListCssClass(String listCssClass) { this.listCssClass = listCssClass; } @StrutsTagAttribute(description = "Property of list objects to get css style from") public void setListCssStyle(String listCssStyle) { this.listCssStyle = listCssStyle; } @StrutsTagAttribute(description = "Property of list objects to get title from") public void setListTitle(String listTitle) { this.listTitle = listTitle; } public void setThrowExceptionOnNullValueAttribute(boolean throwExceptionOnNullValueAttribute) { this.throwExceptionOnNullValueAttribute = throwExceptionOnNullValueAttribute; } }