org.apache.struts.validator.LazyValidatorForm Maven / Gradle / Ivy
/*
* $Id: LazyValidatorForm.java 471754 2006-11-06 14:55:09Z husted $
*
* 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.struts.validator;
import org.apache.commons.beanutils.DynaBean;
import org.apache.commons.beanutils.LazyDynaBean;
import java.util.List;
import java.util.Map;
/**
* Struts Lazy ActionForm which wraps a
* LazyDynaBean.
*
* There isn't really that much to this implementation as most of the
* lazy behaviour is in LazyDynaBean and wrapping
* the LazyDynaBean is handled in the parent
* BeanValidatorForm. The only thing it really does is populate
* indexed properties which are a List type with a
* LazyDynaBean in the get(name, index) method.
*
* Lazy DynaBeans provide several types of lazy
* behaviour:
*
*
*
* - lazy property addition - properties which do not exist
* are automatically added.
*
* - lazy List facilities - automatically grows a
*
List or Array to accomodate the index value being
* set.
*
* - lazy List creation - automatic creation of a
*
List or Array for indexed properties, if
* it doesn't exist. - lazy Map creation - automatic
* creation of a
Map for mapped properties, if it doesn't
* exist.
*
*
*
* Using this lazy ActionForm means that you don't have
* to define the ActionForm's properties in the struts-config.xml.
* However, a word of warning, everything in the Request gets populated into
* this ActionForm circumventing the normal firewall
* function of Struts forms. Therefore you should only take out of this
* form properties you expect to be there rather than blindly populating all
* the properties into the business tier.
*
* Having said that it is not necessary to pre-define properties in the
* struts-config.xml, it is useful to sometimes do so for
* mapped or indexed properties. For example, if you want to use
* a different Map implementation from the default
* HashMap or an array for indexed properties, rather than the
* default List type:
*
*
* <form-bean name="myForm" type="org.apache.struts.validator.LazyValidatorForm">
* <form-property name="myMap" type="java.util.TreeMap" />
* <form-property name="myBeans" type="org.apache.commons.beanutils.LazyDynaBean[]"
* />
* </form-bean>
*
*
* Another reason for defining indexed properties in the
* struts-config.xml is that if you are validating indexed
* properties using the Validator and none are submitted then the indexed
* property will be null which causes validator to fail.
* Pre-defining them in the struts-config.xml will result in a
* zero-length indexed property (array or List) being instantiated, avoiding
* an issue with validator in that circumstance.
*
* This implementation validates using the ActionForm name. If you
* require a version that validates according to the path then it can
* be easily created in the following manner:
*
*
* public class MyLazyForm extends LazyValidatorForm {
*
* public MyLazyForm () {
* super();
* setPathValidation(true);
* }
*
* }
*
*
* Rather than using this class, another alternative is to either use a
* LazyDynaBean or custom version of LazyDynaBean
* directly. Struts now automatically wraps objects which are not
* ActionForms in a BeanValidatorForm. For
* example:
*
*
* <form-bean name="myForm" type="org.apache.commons.beanutils.LazyDynaBean">
* <form-property name="myBeans" type="org.apache.commons.beanutils.LazyDynaBean[]"
* />
* </form-bean>
*
*
* @version $Rev: 471754 $ $Date: 2005-05-07 12:11:38 -0400 (Sat, 07 May 2005)
* $
* @see Commons
* BeanUtils JavaDoc
* @since Struts 1.2.6
*/
public class LazyValidatorForm extends BeanValidatorForm {
// ------------------- Constructors ----------------------------------
/**
* Default Constructor which creates a LazyDynaBean to
* back this form.
*/
public LazyValidatorForm() {
super(new LazyDynaBean());
}
/**
*/
public LazyValidatorForm(DynaBean bean) {
super(bean);
}
// ------------------- DynaBean methods ----------------------------------
/**
* Return an indexed property value.
*
* If the "indexed" property is a List type then any
* missing values are populated with a bean (created in the
* newIndexedBean(name) method - in this implementation this
* is a LazyDynaBean type.
*/
public Object get(String name, int index) {
int size = size(name);
// Get the indexed property
Object value = dynaBean.get(name, index);
// Create missing beans for Lists
if (value == null) {
Object indexedValue = dynaBean.get(name);
if (List.class.isAssignableFrom(indexedValue.getClass())) {
for (int i = size; i <= index; i++) {
value = newIndexedBean(name);
set(name, i, value);
}
}
}
return value;
}
// ------------------- Public methods ----------------------------------
/**
* Return the Map containing the property values.
*
* Provided so that properties can be access using JSTL.
*/
public Map getMap() {
return ((LazyDynaBean) dynaBean).getMap();
}
// ------------------- Protected methods ----------------------------------
/**
* Creates new DynaBean instances to populate an 'indexed'
* property of beans - defaults to LazyDynaBean type.
*
* Override this method if you require a different type of
* DynaBean.
*/
protected DynaBean newIndexedBean(String name) {
return new LazyDynaBean();
}
}