slf4j-ext/src/main/java/org/slf4j/profiler/Util.java

/**
 * Copyright (c) 2004-2011 QOS.ch
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
package org.slf4j.profiler;

import java.text.DecimalFormat;

/**
 * 
 * A collection of utility methods.
 * 
 * @author Ceki Gülcü
 *  
 */
class Util {

    static final long NANOS_IN_ONE_MICROSECOND = 1000;
    static final long NANOS_IN_ONE_MILLISECOND = NANOS_IN_ONE_MICROSECOND * 1000;
    static final long NANOS_IN_ONE_SECOND = NANOS_IN_ONE_MILLISECOND * 1000;
    private static final DecimalFormat DECIMAL_FORMAT = new DecimalFormat("0.000");

    static DurationUnit selectDurationUnitForDisplay(StopWatch sw) {
        return selectDurationUnitForDisplay(sw.elapsedTime());
    }

    static DurationUnit selectDurationUnitForDisplay(long durationInNanos) {
        if (durationInNanos < 10 * NANOS_IN_ONE_MICROSECOND) {
            return DurationUnit.NANOSECOND;
        } else if (durationInNanos < 10 * NANOS_IN_ONE_MILLISECOND) {
            return DurationUnit.MICROSECOND;
        } else if (durationInNanos < 10 * NANOS_IN_ONE_SECOND) {
            return DurationUnit.MILLISSECOND;
        } else {
            return DurationUnit.SECOND;
        }
    }

    static public double convertToMicros(long nanos) {
        return (double) nanos / NANOS_IN_ONE_MICROSECOND;
    }

    static public double convertToMillis(long nanos) {
        return (double) nanos / NANOS_IN_ONE_MILLISECOND;
    }

    static public double convertToSeconds(long nanos) {
        return ((double) nanos / NANOS_IN_ONE_SECOND);
    }

    static String durationInDurationUnitsAsStr(StringBuilder buf, StopWatch sw) {
        DurationUnit du = selectDurationUnitForDisplay(sw);
        return durationInDurationUnitsAsStr(sw.elapsedTime(), du);
    }

    static String durationInDurationUnitsAsStr(long nanos, DurationUnit durationUnit) {
        StringBuilder buf = new StringBuilder();
        switch (durationUnit) {
        case NANOSECOND:
            buf.append(nanos);
            break;
        case MICROSECOND:
            double micros = convertToMicros(nanos);
            buf.append(DECIMAL_FORMAT.format(micros));
            break;
        case MILLISSECOND:
            double millis = convertToMillis(nanos);
            buf.append(DECIMAL_FORMAT.format(millis));
            break;
        case SECOND:
            double seconds = convertToSeconds(nanos);
            buf.append(DECIMAL_FORMAT.format(seconds));
            break;
        }
        return buf.toString();
    }

    static void appendDurationUnitAsStr(StringBuilder buf, DurationUnit durationUnit) {
        switch (durationUnit) {
        case NANOSECOND:
            buf.append("nanoseconds.");
            break;
        case MICROSECOND:
            buf.append("microseconds.");
            break;
        case MILLISSECOND:
            buf.append("milliseconds.");
            break;
        case SECOND:
            buf.append(" seconds.");
            break;
        }
    }
}