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Date: 31 Jul 2003 21:38:31 -0000
Message-ID: <20030731213831.48105.qmail@minotaur.apache.org>
From: rdonkin@apache.org
To: jakarta-commons-cvs@apache.org
Subject: cvs commit:
 jakarta-commons/betwixt/src/java/org/apache/commons/betwixt/strategy
 DefaultObjectStringConverter.java

rdonkin     2003/07/31 14:38:31

  Added:       betwixt/src/java/org/apache/commons/betwixt/strategy
                        DefaultObjectStringConverter.java
  Log:
  Implementation of object <-> String conversion strategy
  
  Revision  Changes    Path
  1.1                  jakarta-commons/betwixt/src/java/org/apache/commons/betwixt/strategy/DefaultObjectStringConverter.java
  
  Index: DefaultObjectStringConverter.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-commons/betwixt/src/java/org/apache/commons/betwixt/strategy/DefaultObjectStringConverter.java,v 1.1 2003/07/31 21:38:31 rdonkin Exp $
   * $Revision: 1.1 $
   * $Date: 2003/07/31 21:38:31 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999-2002 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Commons", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   * 
   * $Id: DefaultObjectStringConverter.java,v 1.1 2003/07/31 21:38:31 rdonkin Exp $
   */
  package org.apache.commons.betwixt.strategy;
  
  import java.text.SimpleDateFormat;
  import java.text.ParseException;
  
  import org.apache.commons.beanutils.ConversionException;
  
  import org.apache.commons.betwixt.expression.Context;
  
  /** 
   * <p>Default string &lt;-&gt; object conversion strategy.</p>
   * <p>
   * This delegates to ConvertUtils except when the type is assignable from <code>java.util.Date</code>
   * but not from <code>java.sql.Date</code>.
   * In this case, the format used is (in SimpleDateFormat terms) <code>EEE MMM dd HH:mm:ss zzz yyyy</code>.
   * This is the same as the output of the toString method on java.util.Date.
   * </p>
   * <p>
   * This should preserve the existing symantic behaviour whilst allowing round tripping of dates
   * (given the default settings).
   * </p>
   */
  public class DefaultObjectStringConverter extends ConvertUtilsObjectStringConverter {
      
      /** Formats Dates to Strings and Strings to Dates */
      private final static SimpleDateFormat formatter = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy");
      
      /**
        * Converts an object to a string representation using ConvertUtils.
        * If the object is a java.util.Date and the type is java.util.Date but not java.sql.Date
        * then SimpleDateFormat formatting to <code>EEE MMM dd HH:mm:ss zzz yyyy</code>
        * will be used. 
        * (This is the same as java.util.Date toString would return.)
        *
        * @param object the object to be converted, possibly null
        * @param type the property class of the object, not null
        * @param flavour a string allow symantic differences in formatting to be communicated (ignored)
        * @return a String representation, not null
        */
      public String objectToString(Object object, Class type, String flavour, Context context) {
          if ( object != null ) {
              if ( object instanceof java.util.Date && isUtilDate( type ) ) {
                  
                  return formatter.format( (java.util.Date) object );
                  
              } else {
                  // use ConvertUtils implementation
                  return super.objectToString( object, type, flavour, context );
              }
          }
          return "";
      }
      
      /**
        * Converts an object to a string representation using ConvertUtils.
        * 
        * @param value the String to be converted, not null
        * @param the property class to be returned (if possible), not null
        * @param flavour a string allow symantic differences in formatting to be communicated (ignored)
        * @return an Object converted from the String, not null
        */
      public Object stringToObject(String value, Class type, String flavour, Context context) {
              if ( isUtilDate( type ) ) {
                  try
                  {
                      return formatter.parse( value );
                  }
                  catch ( ParseException ex )
                  { 
                      handleException( ex );
                      // this supports any subclasses that do not which to throw exceptions
                      // probably will result in a problem when the method will be invoked
                      // but never mind
                      return value;
                  }
              } else {
                  // use ConvertUtils implementation
                  return super.stringToObject( value, type, flavour, context );
              }
      }
      
      /** 
        * Allow subclasses to use a different exception handling strategy.
        * This class throws a <code>org.apache.commons.beanutils.ConversionException</code>
        * when conversion fails.
        * @param e the Exception to be handled
        * @throws org.apache.commons.beanutils.ConversionException when conversion fails
        */
      protected void handleException(Exception e) {
          throw new ConversionException( "String to object conversion failed: " + e.getMessage(), e );
      }
      
      /**
        * Is the given type a java.util.Date but not a java.sql.Date.
        */
      private boolean isUtilDate(Class type) {
          return ( java.util.Date.class.isAssignableFrom(type) 
               && !java.sql.Date.class.isAssignableFrom(type)
               && !java.sql.Time.class.isAssignableFrom(type) 
               && !java.sql.Timestamp.class.isAssignableFrom(type) );
      }
  }
  
  
  

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