Echo.java
/*
** Module : Echo.java
** Abstract : provides a simple mechanism to test a session's connectivity
**
** Copyright (c) 2006-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- -T- --JPRM-- ----------------Description-----------------
** 001 GES 20060725 NEW @28195 First version which provides a simple
** mechanism to test a session's connectivity.
** 002 ECF 20071106 CHG @35880 Replaced Queue with Session.
** 003 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
** You may not represent yourself as Golden Code Development Corporation or FWD.
**
** You may not represent yourself for publicity purposes as associated with
** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
** You may not represent the covered work as solely your work. All modified
** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.net;
import java.io.*;
import java.util.logging.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;
/**
* Helper class which provides a simple mechanism to test a session's
* connectivity.
*
* @author GES
*/
public class Echo
{
/** Logger (safe as a JVM-wide value rather than as context-local). */
private static final CentralLogger LOG =
CentralLogger.get(Echo.class.getName());
/** Tracing flag (enabled at logging level <code>FINEST</code>). */
private static final boolean tracing = LOG.isLoggable(Level.FINEST);
/**
* Test a do-nothing round trip to the other side of this session and
* back with the given data as a payload. If logging is enabled at the
* <code>FINEST</code> level, then details of the payload and the
* elapsed time will be logged.
* <p>
* The protocol's built-in support for <code>ECHO</code> and
* <code>ECHO_REPLY</code> messages is used to implement this feature.
* No special server registration is needed on the other side as long
* as there is a valid session open.
*
* @param payload
* The data to send (and which will be sent back unchanged).
* It may be <code>null</code> (which represents an empty
* payload).
*
* @return Round trip time in milliseconds or -1 if a failure occurred.
*/
public static long ping(Serializable payload)
{
return ping(payload, 0);
}
/**
* Test a do-nothing round trip to the other side of this session and
* back with the given data as a payload. If logging is enabled at the
* <code>FINEST</code> level, then details of the payload and the
* elapsed time will be logged.
* <p>
* The protocol's built-in support for <code>ECHO</code> and
* <code>ECHO_REPLY</code> messages is used to implement this feature.
* No special server registration is needed on the other side as long
* as there is a valid session open.
*
* @param payload
* The data to send (and which will be sent back unchanged).
* It may be <code>null</code> (which represents an empty
* payload).
* @param timeout
* Maximum number of milliseconds to wait for a response. Use
* 0 for an indefinite wait.
*
* @return Round trip time in milliseconds or -1 if a failure occurred.
*/
public static long ping(Serializable payload, int timeout)
{
Session session = SessionManager.get().getSession();
long result = -1;
try
{
Invoker inv = new Invoker(session, timeout);
Object[] args = new Object[] { payload };
if (tracing)
{
TraceHelper.trace(inv, args, LOG, "Echo");
}
else
{
inv.invoke(args);
}
result = inv.getElapsed();
}
catch (Throwable t)
{
// silently ignore failures and return false below
LOG.logp(Level.FINE, Echo.class.getSimpleName(), "ping", "", t);
}
return result;
}
/**
* Helper class to delegate execution of the <code>transactEcho</code>
* method.
*/
private static class Invoker
implements Invocable
{
/** Represents our network session. */
private Session session = null;
/** Timeout in milliseconds. */
private int timeout = 0;
/** Elapsed time in milliseconds. */
private long elapsed = -1;
/**
* Construct an instance that can make an invocation of an echo
* transaction using the given queue.
*
* @param session
* The connection to test.
* @param timeout
* The maximum number of milliseconds to wait for a reply.
*/
public Invoker(Session session, int timeout)
{
this.session = session;
this.timeout = timeout;
}
/**
* Return a text description of the method being invoked.
*
* @return The description.
*/
public String describe()
{
return "ping";
}
/**
* Returns the number of milliseconds of elapsed time during ping
* invocation.
*
* @return The number of elapsed milliseconds or -1 if there was no
* invocation or any error during invocation.
*/
public long getElapsed()
{
return elapsed;
}
/**
* Execute or "run" the object's functionality.
*
* @param args
* The method arguments or <code>null</code> for no arguments.
*
* @return The called method's return value or <code>null</code> if
* there is no return value. Note that this design does not
* allow the caller to determine the difference between a
* <code>void</code> return and a return of a genuine
* <code>null</code>.
*
* @throws Throwable
* If the called method generates any exception or error.
*/
public Object invoke(Object[] args)
throws Throwable
{
Serializable payload = args == null ? null : (Serializable) args[0];
long millis = -1;
Object result = null;
try
{
millis = System.currentTimeMillis();
result = session.echo(payload, timeout, null);
}
finally
{
if (millis != -1)
elapsed = System.currentTimeMillis() - millis;
}
return result;
}
}
}