/**
    * Copyright By Grandsoft Company Limited.  
    * 2013-8-10 上午11:52:36
    */
   package gboat2.base.core.web.md;
   
   import gboat2.base.bridge.debug.DefaultDebugHook;
   import gboat2.base.core.util.JsonVelocityUtil;
   import gboat2.base.core.web.MetadataException;
  
  import java.net.URL;
  
  import net.sf.json.JSONObject;
  
  import org.osgi.framework.Bundle;
  
  /**
   * 
   * 元数据文件扩展处理
   * @author lysming
   * @since jdk1.6
   * @date 2013-8-10
   *  
   */
  
  public class ExtendMetadataHandler extends MetadataHandler {
  	/** 
  	  * {@inheritDoc}   
  	  * @see gboat2.base.core.web.md.MetadataHandler#parseMetadata(net.sf.json.JSONObject, java.net.URL, gboat2.base.core.web.md.MetadataHandlerChain) 
  	  */
  	@Override
  	public JSONObject parseMetadata(JSONObject object, URL url, Bundle bundle, MetadataHandlerChain chain) {
  		if (object != null && object.containsKey("extends")) {
  			String parentPath = object.getString("extends");
  			URL parentUrl = DefaultDebugHook.getInstance().findResource(bundle, parentPath.startsWith("/")?parentPath:"/"+parentPath);
  			if (parentUrl == null) {
  				throw new MetadataException("can't find parent metadata file : " + parentPath);
  			} else {
  				JSONObject parentObject = MetadataSupport.parseMetadata(parentUrl, bundle, chain.clone(chain));
  				if (parentObject != null) {
  					object = JsonVelocityUtil.merge(parentObject, object);
  				}
  			}
  		}
  		return chain.doHandler(object, url, bundle);
  	}
  
  }