python/pydevSrc/com/jetbrains/python/console/pydev/PydevXmlRpcClient.java

package com.jetbrains.python.console.pydev;

import com.intellij.openapi.diagnostic.Logger;
import com.intellij.util.net.NetUtils;
import org.apache.xmlrpc.*;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Arrays;
import java.util.Vector;

/**
 * Subclass of XmlRpcClient that will monitor the process so that if the process is destroyed, we stop waiting
 * for messages from it.
 *
 * @author Fabio
 */
public class PydevXmlRpcClient implements IPydevXmlRpcClient {

  /**
   * Internal xml-rpc client (responsible for the actual communication with the server)
   */
  private final XmlRpcClient impl;

  /**
   * The process where the server is being executed.
   */
  private final Process process;

  /**
   * ItelliJ Logging
   */
  private static final Logger LOG = Logger.getInstance(PydevXmlRpcClient.class.getName());

  private static final long TIME_LIMIT = 60000;


  /**
   * Constructor (see fields description)
   */
  public PydevXmlRpcClient(Process process, int port) throws MalformedURLException {
    XmlRpc.setDefaultInputEncoding("UTF8"); //even though it uses UTF anyway
    impl = new XmlRpcClientLite(NetUtils.getLocalHostString(), port);
    //this.impl = new XmlRpcClient(url, new CommonsXmlRpcTransportFactory(url));
    this.process = process;
  }

  /**
   * Executes a command in the server.
   * <p/>
   * Within this method, we should be careful about being able to return if the server dies.
   * If we wanted to have a timeout, this would be the place to add it.
   *
   * @return the result from executing the given command in the server.
   */
  @Override
  public Object execute(String command, Object[] args) throws XmlRpcException {
    final Object[] result = new Object[]{null};

    //make an async call so that we can keep track of not actually having an answer.
    impl.executeAsync(command, new Vector(Arrays.asList(args)), new AsyncCallback() {

      @Override
      public void handleError(Exception error, URL url, String method) {
        result[0] = new Object[]{error.getMessage()};
      }

      @Override
      public void handleResult(Object recievedResult, URL url, String method) {
        result[0] = recievedResult;
      }
    });

    long started = System.currentTimeMillis();
    //busy loop waiting for the answer (or having the console die).
    while (result[0] == null && System.currentTimeMillis() - started < TIME_LIMIT) {
      try {
        if (process != null) {
          int exitValue = process.exitValue();
          result[0] = new Object[]{String.format("Console already exited with value: %s while waiting for an answer.\n", exitValue)};
          //ok, we have an exit value!
          break;
        }
      }
      catch (IllegalThreadStateException e) {
        //that's ok... let's sleep a bit
        synchronized (this) {
          try {
            wait(10);
          }
          catch (InterruptedException e1) {
            LOG.error(e1);
          }
        }
      }
    }
    if (result[0] == null) {
      throw new XmlRpcException(-1, "Timeout while connecting to server");
    }
    return result[0];
  }
}