Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / statistic / CounterStatistic.java

diff --git a/lib/jetty/org/eclipse/jetty/util/statistic/CounterStatistic.java b/lib/jetty/org/eclipse/jetty/util/statistic/CounterStatistic.java
new file mode 100644 (file)
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+++ b/lib/jetty/org/eclipse/jetty/util/statistic/CounterStatistic.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util.statistic;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.eclipse.jetty.util.Atomics;
+
+
+/* ------------------------------------------------------------ */
+/** Statistics on a counter value.
+ * <p>
+ * Keep total, current and maximum values of a counter that
+ * can be incremented and decremented. The total refers only
+ * to increments.
+ *
+ */
+public class CounterStatistic
+{
+    protected final AtomicLong _max = new AtomicLong();
+    protected final AtomicLong _curr = new AtomicLong();
+    protected final AtomicLong _total = new AtomicLong();
+
+    /* ------------------------------------------------------------ */
+    public void reset()
+    {
+        reset(0);
+    }
+
+    /* ------------------------------------------------------------ */
+    public void reset(final long value)
+    {
+        _max.set(value);
+        _curr.set(value);
+        _total.set(0); // total always set to 0 to properly calculate cumulative total
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     * @param delta the amount to add to the count
+     */
+    public long add(final long delta)
+    {
+        long value=_curr.addAndGet(delta);
+        if (delta > 0)
+        {
+            _total.addAndGet(delta);
+            Atomics.updateMax(_max,value);
+        }
+        return value;
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     */
+    public long increment()
+    {
+        return add(1);
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     */
+    public long decrement()
+    {
+        return add(-1);
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     * @return max value
+     */
+    public long getMax()
+    {
+        return _max.get();
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     * @return current value
+     */
+    public long getCurrent()
+    {
+        return _curr.get();
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     * @return total value
+     */
+    public long getTotal()
+    {
+        return _total.get();
+    }
+
+    /* ------------------------------------------------------------ */
+    @Override
+    public String toString()
+    {
+        return String.format("%s@%x{c=%d,m=%d,t=%d}",this.getClass().getSimpleName(),hashCode(),_curr.get(),_max.get(),_total.get());
+    }
+}