/*
 * Text.java April 2007
 *
 * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
 *
 * 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 org.simpleframework.xml;

import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Retention;

/**
 * The <code>Text</code> annotation is used to represent a field or
 * method that appears as text within an XML element. Methods and
 * fields annotated with this must represent primitive values, which
 * means that the type is converted to and from an XML representation
 * using a <code>Transform</code> object. For example, the primitive 
 * types typically annotated could be strings, integers, or dates.  
 * <p>
 * One restriction on this annotation is that it can only appear once 
 * within a schema class, and it can not appear with the another XML 
 * element annotations, such as the <code>Element</code> annotation. 
 * It can however appear with any number of <code>Attribute</code> 
 * annotations.
 * <pre>
 * 
 *    <example one="value" two="value">
 *       Example text value       
 *    </example>
 * 
 * </pre>
 * Text values are used when an element containing attributes is
 * used to wrap a text value with no child elements. This can be
 * used in place of an element annotation to represent a primitive
 * which is wrapped in a surrounding XML element.
 * 
 * @author Niall Gallagher
 * 
 * @see org.simpleframework.xml.transform.Transformer
 */ 
@Retention(RetentionPolicy.RUNTIME)
public @interface Text {
   
   /**
    * This is used to provide a default value for the text data if
    * the annotated field or method is null. This ensures the the
    * serialization process writes the text data with a value even
    * if the value is null, and allows deserialization to determine
    * whether the value within the object was null or not.
    * 
    * @return this returns the default attribute value to use
    */
   String empty() default "";
   
   /**
    * This is used to determine whether the text is written within 
    * CDATA block or not. If this is set to true then the text is
    * written within a CDATA block, by default the text is output
    * as escaped XML. Typically this is used for large text values.
    * 
    * @return true if the data is to be wrapped in a CDATA block
    */
   boolean data() default false;
   
   /**
    * Determines whether the text value is required within the XML
    * document. Any field marked as not required may not have its
    * value set when the object is deserialized. If an object is to
    * be serialized only a null attribute will not appear in XML.
    * 
    * @return true if the element is required, false otherwise
    */
   boolean required() default true; 
}