solution.java

著名IT公司ILog的APS高级排产优化引擎

package com.power.pipeengine.LPModel;

import java.util.*;
import java.io.*;
import java.net.*;

import com.power.pipeengine.Variable.*;
import com.power.pipeengine.Constraint.*;
import com.power.pipe.*;
import com.power.pipeengine.*;
import com.power.util.Message.*;
import com.power.lpsolver.LPSolve.*;
import com.power.util.urltools.*;

public class Solution {
  private Hashtable _sol = new Hashtable(1000); //(var, value) pairs

  private static final Solution INSTANCE =
      new Solution();

  // Private constructor supresses
  // default public constructor
  private Solution() {
  }

  public static Solution getInstance() {
    return INSTANCE;
  }

  public double getValue(String var) {
    Double value = (Double) _sol.get(var);
    if (null == value) {
      return 0;
    }

    return value.doubleValue();
  }

  public void setSolution(Hashtable sol) {
    _sol = sol;
  }

  private HttpURLConnection urlconn = null;

  private BufferedReader getReaderForURL() throws Exception {
    String urlAddr = GlobalConfig.getInstance().getLPServerURL() +
        "com.power.pipeengine.LP_ReadWriteFile";
    URL url = new URL(urlAddr + "?cmd=ReadModel&FileName=" +
                      GlobalConfig.getInstance().getLPSolverWorkDir() +
                      "model.out");

    BufferedReader d = null;
    InputStream in = null;

    try {
      urlconn = (HttpURLConnection) (url.openConnection());
      urlconn.setRequestMethod("GET");
      in = urlconn.getInputStream();
      d = new BufferedReader(new InputStreamReader(in));
    }
    catch (Exception e) {
      MessageArea.getInstance().addMessage("Error openning URL: " +
                                           urlAddr + "for file: model.out\n");
      return null;
    }

    return d;
  }

  protected void closeURLConnection() {
    if (urlconn != null) {
      urlconn.disconnect();
    }
  }

  protected void publishFileReadingMsg() {
    MessageArea.getInstance().addMessage(
        "Reading file: model.out\n");

  }

  /**
   * Creates a solution and stores it in a solution class.
   */
  public void createSolution() {
    //Vector cons = Model.getInstance().getModelConstraints().getConstraints();
    //int totOriginalVars = Model.getInstance().getTotOriginalVariables();

    try {
      BufferedReader d = URLFileReader.getInstance().getReaderForURL(
          GlobalConfig.getInstance().getFileReadWriteURL(),
          "ReadModel",
          GlobalConfig.getInstance().getLPSolverWorkDir() + "model.out");

      if (null == d) {
        return;
      }

      //read and discard
      String aLine = d.readLine();
      aLine = d.readLine();
      aLine = d.readLine();
      String token = " ";

      aLine = d.readLine();

      while (aLine != null) {
        if (aLine.length() <= 1) {
          break;
        }
        StringTokenizer st = new StringTokenizer(aLine, token);

        String id = new String(st.nextToken());
        String varMPSName = new String(st.nextToken());
        Double varValue = new Double(st.nextToken());

        if (varValue.doubleValue() != 0) {
          _sol.put(Model.getInstance().getRegularVarName(varMPSName),
                   varValue);
        }
        aLine = d.readLine();
      }

      d.close();
      URLFileReader.getInstance().closeURLConnection();
    }
    catch (Exception e) {
      MessageArea.getInstance().addMessage(
          "Error while reading solution file model.out: " + e.getMessage() +
          "\n");
    }

  }

  public void reset() {
    _sol = new Hashtable();
  }
}