DiscriminatedImage.java :  » OSGi » antilia » com » antilia » web » roundpane » Java Open Source

/**
 * This software is provided as IS by Antilia-Soft SL.
 * Copyright 2006-2007.
 */
package com.antilia.web.roundpane;

import org.apache.wicket.Resource;
import org.apache.wicket.ResourceReference;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.image.Image;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.value.ValueMap;

/**
 *  A subclass of {@link Image} that adds noise (a discriminator) to the url every request
 * to prevent the browser from caching the image of different "styles".
 * 
 * @author Ernesto Reinaldo Barreiro (reiern70@gmail.com)
 */
public abstract class DiscriminatedImage extends Image
{
  /**
   * 
   */
  private static final long serialVersionUID = 1L;

  /**
   * Construct.
   * 
   * @see Image#Image(String, IModel)
   * 
   * @param id
   * @param model
   */
  public DiscriminatedImage(String id, IModel<?> model)
  {
    super(id, model);
  }

  /**
   * Construct.
   * 
   * @see Image#Image(String, Resource)
   * 
   * @param id
   * @param imageResource
   */
  public DiscriminatedImage(String id, Resource imageResource)
  {
    super(id, imageResource);
  }

  /**
   * Construct.
   * 
   * @see Image#Image(String, ResourceReference, ValueMap)
   * 
   * @param id
   * @param resourceReference
   * @param resourceParameters
   */
  public DiscriminatedImage(String id, ResourceReference resourceReference,
      ValueMap resourceParameters)
  {
    super(id, resourceReference, resourceParameters);
  }

  /**
   * Construct.
   * 
   * @see Image#Image(String, ResourceReference)
   * 
   * @param id
   * @param resourceReference
   */
  public DiscriminatedImage(String id, ResourceReference resourceReference)
  {
    super(id, resourceReference);
  }

  /**
   * Construct.
   * 
   * @see Image#Image(String, String)
   * 
   * 
   * @param id
   * @param string
   */
  public DiscriminatedImage(String id, String string)
  {
    super(id, string);
  }

  /**
   * Construct.
   * 
   * @see Image#Image(String)
   * 
   * @param id
   */
  public DiscriminatedImage(String id)
  {
    super(id);
  }

  protected abstract String getDiscriminator();
  
  /**
   * @see org.apache.wicket.markup.html.image.Image#onComponentTag(org.apache.wicket.markup.ComponentTag)
   */
  protected void onComponentTag(ComponentTag tag)
  {
    super.onComponentTag(tag);

    String url = tag.getAttributes().getString("src");
    url = url + ((url.indexOf("?") >= 0) ? "&" : "?");
    url = url + "wicket:antiCache=" + getDiscriminator();
    
    tag.put("src", url);
  }

}