From 601fa8a026e7488bbb67e3f809f8255e2e6aeedd Mon Sep 17 00:00:00 2001
From: Robert Greig <rgreig@apache.org>
Date: Mon, 22 Jan 2007 17:30:29 +0000
Subject: (Patch submitted by Rupert Smith) Added configurations for all
 performance test setups to the pom. Commented out to not break build. Waiting
 on junit-toolkit-maven-plugin being added to maven repository.

Create a throttle utility class and tests for it.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk@498720 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/qpid/ping/AbstractPingProducer.java |  3 +-
 .../main/java/org/apache/qpid/ping/Throttle.java   | 66 ++++++++++++++++++++++
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 qpid/java/perftests/src/main/java/org/apache/qpid/ping/Throttle.java

(limited to 'qpid/java/perftests/src/main')

diff --git a/qpid/java/perftests/src/main/java/org/apache/qpid/ping/AbstractPingProducer.java b/qpid/java/perftests/src/main/java/org/apache/qpid/ping/AbstractPingProducer.java
index 513e1609aa..1877a23056 100644
--- a/qpid/java/perftests/src/main/java/org/apache/qpid/ping/AbstractPingProducer.java
+++ b/qpid/java/perftests/src/main/java/org/apache/qpid/ping/AbstractPingProducer.java
@@ -1,5 +1,6 @@
 package org.apache.qpid.ping;
 
+import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.List;
 import java.util.ArrayList;
@@ -35,7 +36,7 @@ public abstract class AbstractPingProducer implements Runnable, ExceptionListene
     private static final Logger _logger = Logger.getLogger(AbstractPingProducer.class);
 
     /** Used to format time stamping output. */
-    protected static final SimpleDateFormat timestampFormatter = new SimpleDateFormat("hh:mm:ss:SS");
+    protected static final DateFormat timestampFormatter = new SimpleDateFormat("hh:mm:ss:SS");
 
     /** Used to tell the ping loop when to terminate, it only runs while this is true. */
     protected boolean _publish = true;
diff --git a/qpid/java/perftests/src/main/java/org/apache/qpid/ping/Throttle.java b/qpid/java/perftests/src/main/java/org/apache/qpid/ping/Throttle.java
new file mode 100644
index 0000000000..9fb637149b
--- /dev/null
+++ b/qpid/java/perftests/src/main/java/org/apache/qpid/ping/Throttle.java
@@ -0,0 +1,66 @@
+package org.apache.qpid.ping;
+
+/**
+ * Throttle is a helper class used in situations where a controlled rate of processing is desired. It allows a certain
+ * number of operations-per-second to be defined and supplies a {@link #throttle} method that can only be called at
+ * most at that rate. The first call to the throttle method will return immediately, subsequent calls will introduce
+ * a short pause to fill out the remainder of the current cycle to attain the desired rate. If there is no remainder
+ * left then it will return immediately.
+ *
+ * <p><table id="crc"><caption>CRC Card</caption>
+ * <tr><th> Responsibilities <th> Collaborations
+ * </table>
+ *
+ * @author Rupert Smith
+ */
+public class Throttle
+{
+    /** Holds the length of the cycle in nano seconds. */
+    long cycleLengthNanos = 0L;
+
+    /** Records the nano time of the last call to the throttle method. */
+    long lastTimeNanos = 0L;
+
+    /**
+     * Sets up the desired rate of operation per second that the throttle method should restrict to.
+     *
+     * @param opsPerSecond The maximum number of calls per second that the throttle method will take.
+     */
+    public void setRate(int opsPerSecond)
+    {
+        // Calculate the length of a cycle.
+        cycleLengthNanos = 1000000000 / opsPerSecond;
+    }
+
+    /**
+     * Introduces a short pause to fill out any time left in the cycle since this method was last called, of length
+     * defined by a call to the {@link #setRate} method.
+     */
+    public void throttle()
+    {
+        // Record the time now.
+        long currentTimeNanos = System.nanoTime();
+
+        // Check if there is any time remaining in the current cycle and introduce a short wait to fill out the
+        // remainder of the cycle if needed.
+        long remainingTimeNanos = cycleLengthNanos - (currentTimeNanos - lastTimeNanos);
+
+        if (remainingTimeNanos > 0)
+        {
+            long milliWait = remainingTimeNanos / 1000000;
+            int nanoWait = (int) (remainingTimeNanos % 1000000);
+
+            try
+            {
+                Thread.currentThread().sleep(milliWait, nanoWait);
+            }
+            catch (InterruptedException e)
+            {
+                // Just ignore this?
+            }
+        }
+
+        // Keep the time of the last call to this method to calculate the next cycle.
+        lastTimeNanos = currentTimeNanos;
+    }
+}
-- 
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