// Copyright 2006 Daniel Gredler

 //

 // 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 net.sf.beanform.prop;

 import net.sf.beanform.util.StringCache;

 import org.apache.hivemind.ApplicationRuntimeException;

 import org.apache.tapestry.services.DataSqueezer;

 import org.apache.tapestry.util.io.SqueezeAdaptor;

 /**

  * Squeezes {@link BeanProperty} objects into and out of HTML and URLs.

  *

  * Since many class names, property names and validator strings will be serialized

  * to the client, but the number of distinct class names, property names and validator

  * strings using this squeezer will usually be small, this implementation keeps small

  * static caches of these strings and their corresponding "abbreviations", which are what

  * is actually sent to the clients. This is extremely important, as URLs are generally

  * <a href="http://support.microsoft.com/default.aspx?scid=KB;en-us;q208427">limited</a>

  * to about 2,000 characters.

  *

  * @author Daniel Gredler

  */

 public class BeanPropertySqueezer implements SqueezeAdaptor {

     private final static StringCache CLASSNAME_CACHE = new StringCache( 100 );

     private final static StringCache PROPERTY_CACHE = new StringCache( 100 );

     private final static StringCache VALIDATOR_CACHE = new StringCache( 100 );

     private final static StringCache INPUT_CACHE = new StringCache( 10 );

     private final static String PREFIX = "BP";

     private final static String DIVIDER = "_";

     public String getPrefix() {

         return PREFIX;

     }

     public Class getDataClass() {

         return BeanProperty.class;

     }

     public String squeeze( DataSqueezer squeezer, Object data ) {

         BeanProperty prop = (BeanProperty) data;

         String c = CLASSNAME_CACHE.getShortVersion( prop.getOwnerClass().getName() );

         String p = PROPERTY_CACHE.getShortVersion( prop.getName() );

         String v = VALIDATOR_CACHE.getShortVersion( prop.getValidators() );

         String i = INPUT_CACHE.getShortVersion( prop.getInput() );

         return PREFIX + DIVIDER + c + DIVIDER + p + DIVIDER + v + DIVIDER + i;

     }

     public Object unsqueeze( DataSqueezer squeezer, String string ) {

         String[] s = string.split( DIVIDER );

         String c = CLASSNAME_CACHE.getRealVersion( s[ 1 ] );

         String p = PROPERTY_CACHE.getRealVersion( s[ 2 ] );

         String v = VALIDATOR_CACHE.getRealVersion( s[ 3 ] );

         String i = INPUT_CACHE.getRealVersion( s[ 4 ] );

         try {

             Class clazz = Class.forName( c );

             BeanProperty prop = new BeanProperty( clazz, p, v, i );

             return prop;

         }

         catch( ClassNotFoundException e ) {

             String msg = BeanPropertyMessages.unsqueezeClassNotFound( string, c );

             throw new ApplicationRuntimeException( msg, e );

         }

     }

 }