get.java

联合国农粮署牵头开发的geonetwork源代码最新版

//=============================================================================
//===	Copyright (C) 2001-2007 Food and Agriculture Organization of the
//===	United Nations (FAO-UN), United Nations World Food Programme (WFP)
//===	and United Nations Environment Programme (UNEP)
//===
//===	This program is free software; you can redistribute it and/or modify
//===	it under the terms of the GNU General Public License as published by
//===	the Free Software Foundation; either version 2 of the License, or (at
//===	your option) any later version.
//===
//===	This program is distributed in the hope that it will be useful, but
//===	WITHOUT ANY WARRANTY; without even the implied warranty of
//===	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//===	General Public License for more details.
//===
//===	You should have received a copy of the GNU General Public License
//===	along with this program; if not, write to the Free Software
//===	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
//===
//===	Contact: Jeroen Ticheler - FAO - Viale delle Terme di Caracalla 2,
//===	Rome - Italy. email: [e-mail]
//==============================================================================

package org.fao.geonet.services.relations;

import java.sql.SQLException;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import jeeves.interfaces.Service;
import jeeves.resources.dbms.Dbms;
import jeeves.server.ServiceConfig;
import jeeves.server.context.ServiceContext;
import jeeves.utils.Util;
import org.fao.geonet.GeonetContext;
import org.fao.geonet.constants.Geonet;
import org.fao.geonet.kernel.DataManager;
import org.jdom.Element;

//=============================================================================

public class Get implements Service
{
	public void init(String appPath, ServiceConfig params) throws Exception {}

	//--------------------------------------------------------------------------
	//---
	//--- Service
	//---
	//--------------------------------------------------------------------------

	public Element exec(Element params, ServiceContext context) throws Exception
	{
		GeonetContext gc = (GeonetContext) context.getHandlerContext(Geonet.CONTEXT_NAME);
		DataManager   dm = gc.getDataManager();

		Dbms dbms = (Dbms) context.getResourceManager().open(Geonet.Res.MAIN_DB);

		int id = Util.getParamAsInt(params, "id");

		String relation = Util.getParam(params, "relation", "normal");

		Set<String> result = new HashSet<String>();

		//--- perform proper queries to retrieve the id set

		if (relation.equals("normal") || relation.equals("full"))
		{
			String query = "SELECT relatedId FROM Relations WHERE id=?";
			result.addAll(retrieveIds(dbms, query, "relatedid", id));
		}

		if (relation.equals("reverse") || relation.equals("full"))
		{
			String query = "SELECT id FROM Relations WHERE relatedId=?";
			result.addAll(retrieveIds(dbms, query, "id", id));
		}

		//--- retrieve metadata and return result

		Element response =  new Element("response");

		for (String mdId : result)
		{
			Element md = dm.getMetadata(context, mdId, false);

			//--- we could have a race condition so, just perform a simple check

			if (md != null)
				response.addContent(md);
		}

		return response;
	}

	//--------------------------------------------------------------------------

	private Set<String> retrieveIds(Dbms dbms, String query, String field, int id) throws SQLException
	{
		List records = dbms.select(query, id).getChildren();

		Set<String> results = new HashSet<String>();

		for (Object o : records)
		{
			Element rec = (Element) o;
			String  val = rec.getChildText(field);

			results.add(val);
		}

		return results;
	}
}

//=============================================================================