content: /*
   * Transform.java May 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 com.aliyun.odps.simpleframework.xml.transform;
  
  /**
   * A <code>Transform</code> represents a an object used to transform
   * an object to and from a string value. This is typically used when
   * either an <code>Attribute</code> or <code>Element</code> annotation
   * is used to mark the field of a type that does not contain any of
   * the XML annotations, and so does not represent an XML structure.
   * For example take the following annotation.
   * <pre>
   * 
   *    &#64;Text
   *    private Date date;
   *    
   * </pre> 
   * The above annotation marks an object from the Java class libraries
   * which does not contain any XML annotations. During serialization
   * and deserialization of such types a transform is used to process
   * the object such that it can be written and read to and from XML.
   * 
   * @author Niall Gallagher
   */
  public interface Transform<T> {
     
     /**
      * This method is used to convert the string value given to an
      * appropriate representation. This is used when an object is
      * being deserialized from the XML document and the value for
      * the string representation is required.
      * 
      * @param value this is the string representation of the value
      * 
      * @return this returns an appropriate instanced to be used
      */
      T read(String value) throws Exception;
      
      /**
       * This method is used to convert the provided value into an XML
       * usable format. This is used in the serialization process when
       * there is a need to convert a field value in to a string so 
       * that that value can be written as a valid XML entity.
       * 
       * @param value this is the value to be converted to a string
       * 
       * @return this is the string representation of the given value
       */
      String write(T value) throws Exception;
  }
  