source: MDService2/trunk/MDService2/src/eu/clarin/cmdi/mdservice/action/DCRProxyAction.java

package eu.clarin.cmdi.mdservice.action;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;

import javax.xml.transform.stream.StreamSource;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import eu.clarin.cmdi.mdservice.model.Termset;

/**
 * Acts as a Struts 2 controller 
 * serves the requests regarding DataCategories
 * it passes them further (Proxy) to the Data Category Registry.
 *   
 * @author vronk 
 *
 */

public class DCRProxyAction extends GenericProxyAction {

        private String proxy_key = "dcregistry";
        
        private String dcrid;
        
        public static String ALL = "all";
        public static String DATCAT = "datcat";
        public static String DATCATS = "datcats";
        
        private static final long serialVersionUID = 1L;
        
        
        public String getDcrid() {
                return dcrid;
        }

        public void setDcrid(String dcrid) {
                this.dcrid = dcrid;
        }

        public Termset getDCR() {               
                String dcr_id="";
                if (getQ()!=null && !getQ().equals("")) dcr_id = getQ();
                // override with dcrid-param
                if (getDcrid()!=null && !getDcrid().equals("")) dcr_id = getDcrid();                    

                Termset res = (Termset) Termset.getTermset(dcr_id);
                if (res==null)          Admin.notifyUser("getDCR(): no termset found for:" + dcr_id);
                //else
                        //Admin.notifyUser("getDCR():" + res.getAttr("id") + ":" + res.getAttr("url") );
                
                return res;
        }
        
        public String getDCRAttr(String key) {  
                Termset dcr = getDCR();
                String val=""; 
                if (dcr!=null) val= dcr.getAttr(key);
                 return val;
        }
        
        @Override
        public String getProxyKey() {
                return proxy_key;
        }
         
        public String getFullFormat() {
                Termset dcr = getDCR();
                String srcformat="", srctype=""; 
                if (dcr!=null){ 
                                srcformat = dcr.getAttr("format");
                                srctype = dcr.getAttr("type");
                } else { 
                         srcformat = ALL;
                         srctype = "datcat";
                }
                        return srctype + "-" + srcformat  + "2" + getFormat();          
        }
        
        public URL getBaseURL() throws MalformedURLException {
                
                if (base_url == null) {
                        base_url = new URL(getBaseURI());
                }
                
                return base_url;
        }
        
        public String getBaseURI() {            
                return getDCRAttr("url");
        }
        
        /**
         * uses base_url and (optionally) id to form a url
         * no id => ?list all datacategories?
         * @return the URL to data category xml format
         * @throws Exception 
         */
        public URL getTargetRequest() throws IOException {

                URL targetURL = null;
        
                //if (getActionkey().equals(DATCATS)) {
                if ((getQ()!=null && !getQ().equals(""))) {
                        //targetURL =new URL(getBaseURI() + "?dcif-mode=all&workingLanguage=" + getLang()) ;
                        targetURL =new URL(getBaseURI() + "?dcif-mode=all&workingLanguage=" + getLang()) ;
                }
                /*
                        if (getQ()==null || getQ().equals("")) {                        
                                        // get all available datcat-sets from terms_setup.xml
                                
                                targetURL =getBaseURL();
                        } else {
                                targetURL =new URL( getBaseURL(), "/" + getQ());
                        }
                        */
//              Admin.notifyUser("DCRProxy.targetURL:" + targetURL);

            return targetURL;
        }
        
        public InputStream getSourceStream() throws IOException {

                InputStream resultStream = null; 
                // if no arguments  - get the local-config file 
                // FIXME: although this should be competence of TermsProxyAction
                if ((getQ().equals(ALL) || getQ()==null || getQ().equals("")) && (getActionkey().equals(DATCATS))) {
                        Admin.notifyUser("serving terms.file:" + Admin.getConfig().getProperty("terms.file"));
                        resultStream = this.getClass().getClassLoader().getResourceAsStream(Admin.getConfig().getProperty("terms.file"));
                } else {
                
                /* need to set Request-Property: Accept to xml 
                 * for to get dcif/xml from DCR-server by means of content negotiation */
                URLConnection urlConnection = getTargetRequest().openConnection();
                
                if (getDCRAttr("format").equals("dcif")) {              
                        urlConnection.setRequestProperty("Accept", "application/dcif+xml");
                        Admin.notifyUser("setting header Accept:" + urlConnection.getRequestProperty("Accept"));
                }
        //urlConnection.setRequestProperty("Accept-Language", getLang());
        
        //
                resultStream = urlConnection.getInputStream();
                }
        return resultStream;    
    
        }

}