Java Code Examples for org.apache.brooklyn.util.text.Strings#makeSizeString()

/** as {@link #forceClearSoftReferences()} but gives control over headroom and max chunk size.
 * it tries to undershoot by headroom as it approaches maximum (and then overshoot)
 * to minimize the chance we take exactly all the memory and starve another thread;
 * and it uses the given max chunk size in cases where the caller wants more precision
 * (the available memory will be fragmented so the smaller the chunks the more it can
 * fill in, but at the expense of time and actual memory provisioned) */
public static String forceClearSoftReferences(long headroom, int maxChunk) {
    final long HEADROOM = 1000*1000;  
    long lastAmount = 0;
    long nextAmount = 0;
    long oldUsed = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
    try {
        List<byte[]> dd = MutableList.of();
        while (true) {
            int size = (int)Math.min(Runtime.getRuntime().freeMemory()-HEADROOM, maxChunk);
            if (size<HEADROOM) {
                // do this to minimize the chance another thread gets an OOME
                // due to us leaving just a tiny amount of memory 
                size = (int) Math.min(size + 2*HEADROOM, maxChunk);
            }
            nextAmount += size;
            dd.add(new byte[size]);
            lastAmount = nextAmount;
        }
    } catch (OutOfMemoryError e) { /* expected */ }
    System.gc(); System.gc();
    long newUsed = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
    return "allocated " + Strings.makeSizeString((lastAmount+nextAmount)/2) +
            (lastAmount<nextAmount ? " +- "+Strings.makeSizeString((nextAmount-lastAmount)/2) : "")
            +" really free memory in "+Strings.makeSizeString(maxChunk)+" chunks; "
            +"memory used from "+Strings.makeSizeString(oldUsed)+" -> "+Strings.makeSizeString(newUsed)+" / "+
                Strings.makeSizeString(Runtime.getRuntime().totalMemory());
}
 

public static String makeBasicUsageString() {
    int present = (int)Math.round(100.0*SoftlyPresent.getUsageTracker().getPercentagePresent());
    return Strings.makeSizeString(Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory())+" / "+
        Strings.makeSizeString(Runtime.getRuntime().maxMemory()) 
        + (Runtime.getRuntime().maxMemory() > Runtime.getRuntime().totalMemory() ? 
            " ("+ Strings.makeSizeString(Runtime.getRuntime().totalMemory()) +" real)"
            : "")
        + " memory"
        + "; " +
        (present>=0 ? present+"% soft-reference maybe retention (of "+SoftlyPresent.getUsageTracker().getTotalEntries()+"); " : "") +
        Thread.activeCount()+" threads";
}
 

@Override
public String toString() {
    return "Stream["+streamType+"/"+Strings.makeSizeString(streamSize.get())+"]";
}
 

public String getTotalString() {
    return "totals: out="+Strings.makeSizeString(bytesOut.get())+" in="+Strings.makeSizeString(bytesIn.get());
}