src/org/objectweb/cjdbc/controller/loadbalancer/tasks/BeginTask.java

説明を見る。

package org.objectweb.cjdbc.controller.loadbalancer.tasks;

import java.sql.Connection;
import java.sql.SQLException;

import org.objectweb.cjdbc.controller.backend.DatabaseBackend;
import org.objectweb.cjdbc.controller.connection.AbstractConnectionManager;
import org.objectweb.cjdbc.controller.loadbalancer.BackendWorkerThread;

public class BeginTask extends AbstractTask
{
  private String login;

  private int    transactionId;

  private long   timeout;

  public BeginTask(int nbToComplete, int totalNb, long timeout, String login,
      int transactionId)
  {
    super(nbToComplete, totalNb);
    this.login = login;
    this.transactionId = transactionId;
    this.timeout = timeout;
  }

  public void execute(BackendWorkerThread backendThread) throws SQLException
  {
    DatabaseBackend backend = backendThread.getBackend();
    if (backend.isDisabling())
    {
      // Backend is disabling, we do not execute queries except the one in the
      // transaction we already started. Just notify the completion for the
      // others.
      notifyCompletion();
      return;
    }

    try
    {
      AbstractConnectionManager cm = backend.getConnectionManager(login);
      if (cm == null)
      {
        SQLException se = new SQLException(
            "No Connection Manager for Virtual Login:" + login);
        try
        {
          notifyFailure(backendThread, 1, se);
        }
        catch (SQLException ignore)
        {

        }
        throw se;
      }

      Connection c = cm.getConnection(transactionId);

      // Sanity check
      if (c == null)
      { // Bad connection
        SQLException se = new SQLException(
            "No more connection to start a new transaction.");
        try
        { // All backends failed, just ignore
          if (!notifyFailure(backendThread, timeout, se))
            return;
        }
        catch (SQLException ignore)
        {
        }
      }

      c.setAutoCommit(false);
      notifySuccess();
      backend.startTransaction(new Long(transactionId));
    }
    catch (Exception e)
    {
      try
      {
        if (!notifyFailure(backendThread, timeout, new SQLException(e
            .getMessage())))
          return;
      }
      catch (SQLException ignore)
      {
      }
      String msg = "Failed to begin transaction " + transactionId
          + " on backend " + backend.getName() + " (" + e + ")";
      backendThread.getLogger().error(msg);
      throw new SQLException(msg);
    }
  }

  public String toString()
  {
    return "BeginTask (" + transactionId + ")";
  }
}

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