webxmlqslsp.java

数字图书馆的互操作接口

package dli2fe.sample;

/**
 * Title:        Digial Library Interoperable Interface Fudan Edition
 * Description:  This project contains all the classes required for DLI2FE interface. Developers use these classes to implement the wrapper and client side codes. The basic functions of DLI2FE is as follows:
 * Search: Search a digital library source site.
 * Metadata: Fetch metadata for a site.
 * ResultAccess: Get results for a given query.
 * DLI2FE uses Dublin Core as the basic attribute model, DAV/DASL as the general XML-based query language and CORBA as distributed object transportation mechanism.
 * Copyright:    Copyright (c) 2001
 * Company:      Fudan University
 * @author Carl Tao
 * @version 1.0
 */
import dli2fe.*;
import javax.swing.Timer;
import java.awt.event.*;
import java.util.Hashtable;
import org.w3c.dom.*;
import dli2fe.xml.NodeListImpl;
import dli2fe.helpers.*;

/* sample parameters for dli2fe.sample.Client
dli2fens:http://localhost:9524/ search 1 "<basicsearch xmlns='DAV:' xmlns:dc='http://purl.org/metadata/dublin_core#' xmlns:webxmlqs='http://www.cs.fudan.edu.cn/WebXMLQS/#'> <where> <and> <like> <prop><webxmlqs:QueryClause/></prop> <literal>select b.name,b.date from customer b where b in pages(http://america/zb/x.xml,5,20) and b.orders.item.number>1 </literal> </like> </and> </where> </basicsearch>" 1
dli2fens:http://localhost:9524/ search 1 " <basicsearch xmlns='DAV:' xmlns:dc='http://purl.org/metadata/dublin_core#' xmlns:webxmlqs='http://www.cs.fudan.edu.cn/WebXMLQS/#'> <where> <and> <eq> <prop><webxmlqs:StartURL/></prop> <literal>C:\Inetpub\wwwroot\postinfo.html</literal> </eq> <eq> <prop><webxmlqs:Depth/></prop> <literal>1</literal> </eq> <eq> <prop><webxmlqs:KeySearch/></prop> <literal>用户</literal> </eq> <eq> <prop><webxmlqs:KeyOp/></prop> <literal>1</literal></eq></and> </where> </basicsearch>" 1
dli2fens:http://localhost:9524/ search 1 " <basicsearch xmlns='DAV:' xmlns:dc='http://purl.org/metadata/dublin_core#' xmlns:webxmlqs='http://www.cs.fudan.edu.cn/WebXMLQS/#'> <where> <and> <eq> <prop><webxmlqs:StartURL/></prop> <literal>C:\Inetpub\wwwroot\postinfo.html</literal> </eq> <eq> <prop><webxmlqs:Depth/></prop> <literal>1</literal> </eq> <eq> <prop><webxmlqs:KeySearch/></prop> <literal>用户</literal> </eq> <eq> <prop><webxmlqs:KeyOp/></prop> <literal>0</literal></eq><eq> <prop><webxmlqs:KeySearch/></prop> <literal>网页</literal> </eq> <eq> <prop><webxmlqs:KeyOp/></prop> <literal>0</literal></eq></and> </where> </basicsearch>" 1
*/

public class WebxmlqsLSP implements Metadata, Searcher, ResultAccess {
  static int SIDGenerator = 0;
  static final String COLL_NAME = "WebXMLQS";
  public static final int keyNum = 3;
  public static final String Namespace = "http://www.cs.fudan.edu.cn/DLI2FE/1.0#";
  public static final String WebNamespace = "http://www.cs.fudan.edu.cn/WebXMLQS/1.0#";
  public static final String simplepage = "http://10.11.10.33/cgi/simple.dll?simplesearch";
  public static final String complexpage = "http://10.11.10.33/cgi/cplex.dll?cplexsearch";
  public static final String xmlpage = "http://10.11.10.33/cgi/xmlsearch.dll?inputstring";
  Hashtable sessions = new Hashtable();
  String queryClauset,startURLt,deptht;
  String[] keySearcht,keyOpt;
  int keySearchNum;
  int keyOpNum;
  int numDocst;                    //需要的查询结果数
  String tempResult;


  class Session implements ActionListener {

    int SID;
    Webxmlqs wx;
    Timer timer;
    WebxmlqsLSP container;
    boolean done;
    long endTime;

    Session(WebxmlqsLSP wxlsp, String queryString) throws DLI2FEException {
      container = wxlsp;
      SID = container.getNextSID();
      wx = new Webxmlqs(queryString);
      endTime = System.currentTimeMillis() + DLI2FE.DEFAULT_TIMEOUT*1000;
      timer = new Timer(DLI2FE.DEFAULT_TIMEOUT*1000, this);
      timer.setRepeats(false);
      timer.start();
      done = false;
      wx.searchWebxmlqs();
      done = true;
    }

    public void extendTimeout(int seconds) {
      endTime = System.currentTimeMillis() + seconds * 1000;
      timer.stop();
      timer.setDelay(seconds*1000);
      timer.setRepeats(false);
      timer.start();
    }

    public int getTimeout() {
      return (int)((endTime - System.currentTimeMillis())/1000);
    }

    // for interface ActionListener to receive timer's message
    public void actionPerformed(ActionEvent e) {
      if (!done) {
        timer.stop();
        timer.setDelay(10000);
        timer.setRepeats(false);
        timer.start();
      } else
        container.removeSession(this);
    }

    public int getSessionID() {
      return SID;
    }

    public Webxmlqs getWX() {
      return wx;
    }

    public String toString() {
      return "[ SID : " + SID + "]";
    }
  }

  public int getNextSID() {
    return ++SIDGenerator;
  }

  public WebxmlqsLSP() {

  }

  public String toString() {
    return "WebXMLQS";
  }

  public void addSession(Session session) {
    sessions.put(new Integer(session.getSessionID()), session);
  }

  public void removeSession(Object handle) {
    Session session = (Session)handle;
    System.out.println("Session " + session + " timed out!");
    sessions.remove(new Integer(session.getSessionID()));
  }

  String notNull(String str) {
    return str == null ? "" : str;
  }

  void parseQuery(XMLObject query) throws DLI2FEException {                    //分析开始的xml的查询，得到各字段的值
    String value,local;
    keySearchNum = 0;
    keyOpNum = 0;
    dli2fe.xml.XMLObject xml = dli2fe.xml.XMLObject.create(query);
    // Match all 'like' or 'eq' elements
    NodeListImpl list = new NodeListImpl(xml.getElement().getElementsByTagName("like"));
    NodeListImpl list1 = new NodeListImpl(xml.getElement().getElementsByTagName("eq"));
    list.addAll(list1);
    int j = list.size();
    keySearcht = new String[j];
    keyOpt = new String[j];
    for (int i = 0; i < j; i++) {
      Element el = (Element)list.item(i);
      NodeList l = el.getElementsByTagName("prop");
      if (l.getLength() != 1)
        throw new DLI2FEException(DLI2FEException.MALFORMED_XML_EXC, "Invalid " + el.getTagName() +" element, 'prop' expected.");
      Element prop = (Element)l.item(0);
      l = prop.getElementsByTagName("*");
      if (l.getLength() != 1)
        throw new DLI2FEException(DLI2FEException.MALFORMED_XML_EXC, "Invalid " + el.getTagName() +" element, prop expected.");
      local = l.item(0).getLocalName();
      l = el.getElementsByTagName("literal");
      if (l.getLength() != 1)
        throw new DLI2FEException(DLI2FEException.MALFORMED_XML_EXC, "Invalid " + el.getTagName() +" element, 'literal' expected.");
      else
         value = l.item(0).getFirstChild().getNodeValue().trim();
      if ("QueryClause".equals(local))
        queryClauset = value;
      else if ("StartURL".equals(local))
        startURLt = value;
      else if ("Depth".equals(local))
        deptht = value;
      else if ("KeySearch".equals(local))
        keySearcht[keySearchNum++] = value;
      else if ("KeyOp".equals(local))
        keyOpt[keyOpNum++] = value;
      else
        throw new DLI2FEException(DLI2FEException.MALFORMED_XML_EXC, "Invalid property " + local +".");
    }
    if (keySearchNum != keyOpNum)
       throw new DLI2FEException(DLI2FEException.MALFORMED_XML_EXC, "Invalid key. ");
  }

  public void getSiteMetadata (XMLObject theSiteMetadata) throws DLI2FEException{
    theSiteMetadata.setString("<SiteMetadata xmlns='" + DLI2FE.Namespace +"'>\n<version>1.0</version> " +
      "<collectionName>" + COLL_NAME + "</collectionName> <baseURI>dli2fens:http://localhost:9524/webxmlqs</baseURI> <ctgrName>WebXMLQS</ctgrName>\n" +
      "<contentConstraint/> <boolOp>and</boolOp> <language>zh_CN</language>\n</SiteMetadata>");
  }

  public void getAttributeInfo (String ctgrName,
                                XMLObject attributeInfo) throws DLI2FEException {
    if ("WebXMLQS".equals(ctgrName)) {
      attributeInfo.setString("<AttributeInfo collectionName='" + COLL_NAME + "' xmlns='" + Namespace +
      "' xmlns:dc='" + DublinCore.Namespace + "' xmlns:webxmlqs='" + WebNamespace + "'> \n" +
      "<attr attrName='webxmlqs:QueryClause'><searchable/><operator>eq</operator></attr>\n" +
      "<attr attrName='webxmlqs:StartURL'><searchable/><operator>eq</operator></attr>\n" +
      "<attr attrName='webxmlqs:Depth'><searchable/><operator>eq</operator></attr>\n" +
      "<attr attrName='webxmlqs:KeySearch'><searchable/><operator>eq</operator></attr>\n" +
      "<attr attrName='webxmlqs:KeyOp'><searchable/><operator>eq</operator></attr>\n" +
      "<attr attrName='dc:Title'><retrievable/><operator/></attr>\n" +
      "<attr attrName='dc:Identifier'><retrievable/><operator/></attr>\n" +
      "<attr attrName='dc:Description'><retrievable/><operator/></attr>\n" +
      "<attr attrName='webxmlqs:KeyName'><retrievable/><operator/></attr>\n" +
      "<attr attrName='webxmlqs:KeyValue'><retrievable/><operator/></attr>\n" +
      "</AttributeInfo>");
    }
    else
      throw new DLI2FEException(DLI2FEException.INVALID_REQUEST_EXC, "Category " + notNull(ctgrName) + " not supported.");
  }

  public String createHead(String contentString)  throws DLI2FEException {
      String result = "<SearchResult xmlns='" + DLI2FE.Namespace +"' xmlns:webxmlqs='" +
      WebNamespace + "'>\n";
      result += contentString + "</SearchResult>";
      return result;
  }

  public String getqueryString() throws DLI2FEException {
     String tempString = "";
     if (queryClauset != null)
       {tempString = xmlpage + "&Instring=" + queryClauset;}
    else
       {startURLt = startURLt == null ? "http://www.sina.com.cn" : startURLt.trim();
        deptht = deptht == null ? "2" : deptht.trim();
        //numDocst = numDocst == null ? "10" : numDocst.trim();
        if (keySearchNum > 1)
           {
            for (int i=0; i<keyNum;i++)
             {
               keySearcht[i] = keySearcht[i] == null ? "" : keySearcht[i].trim();
               keyOpt[i] = keyOpt[i] == null ? "0" : keyOpt[i].trim();
             }
            tempString = complexpage + "&Url=" + startURLt;
            for (int i=0; i<keyNum;i++)
             {
              int j = i+1;
              tempString += "&Keyword" + j + "=" + keySearcht[i] +
                            "&Key" + j + "=" + keyOpt[i];
             }
             tempString += "&Depth=" + deptht +"&Totallink=" + numDocst;
            }
         else
           {
             keySearcht[0] = keySearcht[0] == null ? "" : keySearcht[0].trim();
             tempString = simplepage + "&Url=" + startURLt + "&Keyword=" + keySearcht[0]
                          + "&Depth=" + deptht +"&Totallink=" + numDocst;
           }
       }
    /*String result = createHead(tempString);
    return result;*/
    return tempString;
  }

  // XML query String example:
  /*
  <basicsearch xmlns='DAV:' xmlns:dc='http://purl.org/metadata/dublin_core#'
      xmlns:webxmlqs='http://www.cs.fudan.edu.cn/WebXMLQS/#'>
    <where>
      <and>
        <like>
          <prop><webxmlqs:QueryClause/></prop>
          <literal>select * from a where c=a;</literal>
        </like>
      </and>
    </where>
  </basicsearch>
  */

  //html query String example:
  /*
  <basicsearch xmlns='DAV:' xmlns:dc='http://purl.org/metadata/dublin_core#'
      xmlns:webxmlqs='http://www.cs.fudan.edu.cn/WebXMLQS/#'>
    <where>
      <and>
        <eq>
          <prop><webxmlqs:StartURL/></prop>
          <literal>C:\Inetpub\wwwroot\postinfo.html</literal>
        </eq>
        <eq>
          <prop><webxmlqs:Depth/></prop>
          <literal>1</literal>
        </eq>
        <eq>
          <prop><webxmlqs:KeySearch/></prop>
          <literal>用户</literal>
        </eq>
        <eq>
          <prop><webxmlqs:KeyOp/></prop>
          <literal>1</literal>
        </eq>
      </and>
    </where>
  </basicsearch>
  */

  public void search (int clientSID,
                      XMLObject subcols,
                      XMLObject query,
                      int numDocs,
                      XMLObject docPropList,
                      XMLObject queryOptions,
                      org.omg.CORBA.IntHolder expectedTotal,
                      org.omg.CORBA.IntHolder serverSID,
                      XMLObject result) throws DLI2FEException {
    String queryString;
    numDocst=numDocs;
    expectedTotal.value = Searcher.UNKNOWABLE;
    parseQuery(query);
    if ((queryClauset == null) && (keySearchNum == 0))
      throw new DLI2FEException(DLI2FEException.BAD_QUERY_EXC, "Query for nothing");
    queryString = getqueryString();
    Session session = new Session(this, queryString);
    sessions.put(new Integer(session.getSessionID()), session);
    serverSID.value = session.getSessionID();
    if ((expectedTotal.value = session.getWX().getNumDocs()) == 0) {
      return;
    }
    tempResult = session.getWX().getResultString();
    result.setString(tempResult);
  }





  public void getSessionInfo (int serverSID,
                              org.omg.CORBA.IntHolder expectedTotal,
                              org.omg.CORBA.IntHolder stateTimeout) throws DLI2FEException {
    Session session = (Session)sessions.get(new Integer(serverSID));
    if (session == null)
      throw new DLI2FEException(DLI2FEException.INVALID_SESSIONID_EXC, "Invalid session ID.");
    expectedTotal.value = session.getWX().getNumDocs();
    stateTimeout.value = session.getTimeout();
  }

  public void getDocs (int serverSID,
                       int reqID,
                       XMLObject docPropList,
                       String docsToGet,
                       XMLObject res) throws DLI2FEException {
    // ignores reqID, docPropList
    Session session = (Session)sessions.get(new Integer(serverSID));
    if (session == null)
      throw new DLI2FEException(DLI2FEException.INVALID_SESSIONID_EXC, "Invalid session ID.");
    //res.setString(session.getWX.createResult(docsToGet));
  }

  public void extendStateTimeout (int serverSID,
                                  int secondsToExtend) throws DLI2FEException {
    Session session = (Session)sessions.get(new Integer(serverSID));
    if (session == null)
      throw new DLI2FEException(DLI2FEException.INVALID_SESSIONID_EXC, "Invalid session ID.");
    session.extendTimeout(secondsToExtend);
  }

  // Do nothing
  public void cancelRequest (int serverSID,
                             int reqID) throws DLI2FEException {
    return;
  }


  public static void main(String[] args) throws Exception{
    WebxmlqsLSP WebxmlqsLSP1 = new WebxmlqsLSP();
    ServerCORBATransport t = new ServerCORBATransport();
    t.addLSP(WebxmlqsLSP1);
  }
}