org.xbib.helianthus.common.util.UnitFormatter Maven / Gradle / Ivy

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package org.xbib.helianthus.common.util;

/**
 * Formats a duration and a buffer size into a {@link String} or a {@link StringBuilder}.
 */
public final class UnitFormatter {

    private UnitFormatter() {
    }

    /**
     * Appends the human-readable representation of the specified byte-unit {@code size} to the specified
     * {@link StringBuffer}.
     */
    public static void appendSize(StringBuilder buf, long size) {
        if (size >= 104857600) { // >= 100 MiB
            buf.append(size / 1048576).append("MiB");
        } else if (size >= 102400) { // >= 100 KiB
            buf.append(size / 1024).append("KiB");
        } else {
            buf.append(size).append('B');
        }
    }

    /**
     * Appends the human-readable representation of the duration between the specified {@code startTimeNanos}
     * and {@code endTimeNanos} to the specified {@link StringBuilder}.
     */
    public static void appendElapsed(StringBuilder buf, long startTimeNanos, long endTimeNanos) {
        final long elapsedNanos = endTimeNanos - startTimeNanos;
        if (elapsedNanos >= 100000000000L) { // >= 100 s
            buf.append(elapsedNanos / 1000000000L).append('s');
        } else if (elapsedNanos >= 100000000L) { // >= 100 ms
            buf.append(elapsedNanos / 1000000L).append("ms");
        } else if (elapsedNanos >= 100000L) { // >= 100 us
            buf.append(elapsedNanos / 1000L).append("\u00B5s");
        } else {
            buf.append(elapsedNanos).append("ns");
        }
    }

    /**
     * A shortcut method that calls {@link #appendElapsed(StringBuilder, long, long)} and
     * {@link #appendSize(StringBuilder, long)}, concatenated by {@code ", "}.
     */
    public static void appendElapsedAndSize(
            StringBuilder buf, long startTimeNanos, long endTimeNanos, long size) {
        appendElapsed(buf, startTimeNanos, endTimeNanos);
        buf.append(", ");
        appendSize(buf, size);
    }

    /**
     * Creates a new {@link StringBuilder} whose content is the human-readable representation of the duration
     * between the specified {@code startTimeNanos} and {@code endTimeNanos}.
     */
    public static StringBuilder elapsed(long startTimeNanos, long endTimeNanos) {
        final StringBuilder buf = new StringBuilder(16);
        appendElapsed(buf, startTimeNanos, endTimeNanos);
        return buf;
    }

    /**
     * Creates a new {@link StringBuilder} whose content is the human-readable representation of the byte-unit
     * {@code size}.
     */
    public static StringBuilder size(long size) {
        final StringBuilder buf = new StringBuilder(16);
        appendSize(buf, size);
        return buf;
    }

    /**
     * Similar to {@link #appendElapsedAndSize(StringBuilder, long, long, long)} except that this method
     * creates a new {@link StringBuilder}.
     */
    public static StringBuilder elapsedAndSize(long startTimeNanos, long endTimeNanos, long size) {
        final StringBuilder buf = new StringBuilder(16);
        appendElapsedAndSize(buf, startTimeNanos, endTimeNanos, size);
        return buf;
    }
}