com.google.common.collect.MinMaxPriorityQueue#removeLast ( )源码实例Demo

/**
 * Used when the cache is growing past its max size to clone in a single pass.
 * Removes least recently used tables to get size of cache below its max size by
 * the overage amount.
 */
public PTableCache cloneMinusOverage(long overage) {
    assert(overage > 0);
    int nToRemove = Math.max(MIN_REMOVAL_SIZE, (int)Math.ceil((currentByteSize-maxByteSize) / ((double)currentByteSize / size())) + 1);
    MinMaxPriorityQueue<PTableRef> toRemove = BUILDER.expectedSize(nToRemove).create();
    PTableCache newCache = new PTableCache(this.size(), this.maxByteSize, this.timeKeeper);
    
    long toRemoveBytes = 0;
    // Add to new cache, but track references to remove when done
    // to bring cache at least overage amount below it's max size.
    for (PTableRef tableRef : tables.values()) {
        newCache.put(tableRef.table.getKey(), new PTableRef(tableRef));
        toRemove.add(tableRef);
        toRemoveBytes += tableRef.estSize;
        if (toRemoveBytes - toRemove.peekLast().estSize > overage) {
            PTableRef removedRef = toRemove.removeLast();
            toRemoveBytes -= removedRef.estSize;
        }
    }
    for (PTableRef toRemoveRef : toRemove) {
        newCache.remove(toRemoveRef.table.getKey());
    }
    return newCache;
}
 

/**
 * Used when the cache is growing past its max size to clone in a single pass.
 * Removes least recently used tables to get size of cache below its max size by
 * the overage amount.
 */
public PMetaDataCache cloneMinusOverage(long overage) {
    assert(overage > 0);
    int nToRemove = Math.max(MIN_REMOVAL_SIZE, (int)Math.ceil((currentByteSize-maxByteSize) / ((double)currentByteSize / size())) + 1);
    MinMaxPriorityQueue<PTableRef> toRemove = BUILDER.expectedSize(nToRemove).create();
    PMetaDataCache newCache = new PMetaDataCache(this.size(), this.maxByteSize, this.timeKeeper, this.tableRefFactory);
    
    long toRemoveBytes = 0;
    // Add to new cache, but track references to remove when done
    // to bring cache at least overage amount below it's max size.
    for (PTableRef tableRef : this.tables.values()) {
        newCache.put(tableRef.getTable().getKey(), tableRefFactory.makePTableRef(tableRef));
        toRemove.add(tableRef);
        toRemoveBytes += tableRef.getEstimatedSize();
        while (toRemoveBytes - toRemove.peekLast().getEstimatedSize() >= overage) {
            PTableRef removedRef = toRemove.removeLast();
            toRemoveBytes -= removedRef.getEstimatedSize();
        }
    }
    for (PTableRef toRemoveRef : toRemove) {
        newCache.remove(toRemoveRef.getTable().getKey());
    }
    return newCache;
}