PartitionGranularity.java

/*******************************************************************************
 * Copyright (c) 2011 The Board of Trustees of the Leland Stanford Junior University
 * as Operator of the SLAC National Accelerator Laboratory.
 * Copyright (c) 2011 Brookhaven National Laboratory.
 * EPICS archiver appliance is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution.
 *******************************************************************************/
package org.epics.archiverappliance.common;

/**
 * A small enum for defining the granularity of the partition. 
 * Used principally by the PB storage plugin.
 * The time intervals here have to fit within each other for certain optimizations to work.
 * That is, 5 minutes completely fits within all the granularities larger than it (15,30,60,day,month,year) and 15 minutes completely fits within all the granularities larger than it and so on... 
 * @author mshankar
 *
 */
public enum PartitionGranularity {
	PARTITION_5MIN(5*60),
	PARTITION_15MIN(15*60),
	PARTITION_30MIN(30*60),
	PARTITION_HOUR(60*60),
	PARTITION_DAY(24*60*60),
	PARTITION_MONTH(31*24*60*60),
	PARTITION_YEAR(366*24*60*60);
	
	int approxSecondsPerChunk;
	int approxMinutesPerChunk;
	
	PartitionGranularity(int approxSecondsPerChunk) {
		this.approxSecondsPerChunk = approxSecondsPerChunk;
		this.approxMinutesPerChunk = this.approxSecondsPerChunk/60;
	}
	
	public boolean isSmallerThan(PartitionGranularity other) {
		return this.approxSecondsPerChunk < other.approxSecondsPerChunk;
	}

	public int getApproxSecondsPerChunk() {
		return approxSecondsPerChunk;
	}
	
	public PartitionGranularity getNextLargerGranularity() {
		switch(this) {
		case PARTITION_5MIN :  return PARTITION_15MIN;
		case PARTITION_15MIN : return PARTITION_30MIN;
		case PARTITION_30MIN : return PARTITION_HOUR;
		case PARTITION_HOUR : return PARTITION_DAY;
		case PARTITION_DAY : return PARTITION_MONTH;
		case PARTITION_MONTH: return PARTITION_YEAR;
		case PARTITION_YEAR: return null;
		default: return null;
		}
	}

	public int getApproxMinutesPerChunk() {
		return approxMinutesPerChunk;
	}
}