Struts example source code file (EnumTypeConverter.java)

This example Struts source code file (EnumTypeConverter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

class, class, defaulttypeconverter, deprecated, deprecated, enumtypeconverter, object, object, override, string, string, util

The Struts EnumTypeConverter.java source code

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * Licensed 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.opensymphony.xwork2.conversion.impl;

import java.util.Map;


/**
 * <code>EnumTypeConverter
 *
 * <!-- START SNIPPET: description -->
 * This class converts java 5 enums to String and from String[] to enum.
 * <p/>
 * One of Java 5's improvements is providing enumeration facility.
 * Up to now, there existed no enumerations. The only way to simulate was the so-called int Enum pattern:
 * {code}
 * public static final int SEASON_WINTER = 0;
 * public static final int SEASON_SPRING = 1;
 * public static final int SEASON_SUMMER = 2;
 * public static final int SEASON_FALL   = 3;
 * {code}
 * <p/>
 * Java 5.0 now provides the following construct:
 * {code}
 * public static enum Season { WINTER, SPRING, SUMMER, FALL };
 * {code}
 * <!-- END SNIPPET: description -->
 *
 * <!-- START SNIPPET: example -->
 * h3. Implementing Java 5 Enumeration Type Conversion
 * <p/>
 * 1. myAction-conversion.properties*
 * <p/>
 * Place a myAction-conversion.properties-file in the path of your Action.
 * Add the following entry to the properties-file:
 * {code}
 * nameOfYourField=fullyClassifiedNameOfYourConverter
 * {code}
 *  
 * <p/>
 * 2. myAction.java*
 * Your action contains the _enumeration_:
 * {code}
 * public enum Criticality {DEBUG, INFO, WARNING, ERROR, FATAL}
 * {code}
 *  
 * * Your action contains the _private field_:
 * {code}
 * private myEnum myFieldForEnum;
 * {code}
 *  
 * Your action contains _getters and setters_ for your field:
 * {code}
 * public myEnum getCriticality() {
 *         return myFieldForEnum;
 *     }
 *
 *     public void setCriticality(myEnum myFieldForEnum) {
 *         this.myFieldForEnum= myFieldForEnum;
 *     }
 * {code}
 * <p/>
 * 3. JSP*
 * <p/>
 *     In your jsp you can access an enumeration value just normal by using the known <ww:property>-Tag:
 * {code}
 * <ww:property value="myField"/>
 * {code}
 * <!-- END SNIPPET: example -->
 *
 * @author Tamara Cattivelli
 * @author <a href="mailto:hermanns@aixcept.de">Rainer Hermanns
 * @version $Id: EnumTypeConverter.java 894090 2009-12-27 18:18:29Z martinc $
 * @deprecated Since Struts 2.1.0 as enum support is now built into XWork
 */
@Deprecated public class EnumTypeConverter extends DefaultTypeConverter {

    /**
     * Converts the given object to a given type. How this is to be done is implemented in toClass. The OGNL context, o
     * and toClass are given. This method should be able to handle conversion in general without any context or object
     * specified.
     *
     * @param context - OGNL context under which the conversion is being done
     * @param o       - the object to be converted
     * @param toClass - the class that contains the code to convert to enumeration
     * @return Converted value of type declared in toClass or TypeConverter.NoConversionPossible to indicate that the
     *         conversion was not possible.
     */
    @Override
    public Object convertValue(Map<String, Object> context, Object o, Class toClass) {
        if (o instanceof String[]) {
            return convertFromString(((String[]) o)[0], toClass);
        } else if (o instanceof String) {
            return convertFromString((String) o, toClass);
        }

        return super.convertValue(context, o, toClass);
    }

    /**
     * Converts one or more String values to the specified class.
     * @param value - the String values to be converted, such as those submitted from an HTML form
     * @param toClass - the class to convert to
     * @return the converted object
     */
    public java.lang.Enum convertFromString(String value, Class toClass) {
        return Enum.valueOf(toClass, value);
    }

}