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package com.salesforce.phoenix.expression.function;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import com.google.common.collect.Lists;
import com.salesforce.phoenix.expression.CoerceExpression;
import com.salesforce.phoenix.expression.Expression;
import com.salesforce.phoenix.expression.LiteralExpression;
import com.salesforce.phoenix.schema.ColumnModifier;
import com.salesforce.phoenix.schema.PDataType;
import com.salesforce.phoenix.schema.PDataType.PDataCodec;
import com.salesforce.phoenix.schema.tuple.Tuple;
/**
*
* Class encapsulating the process for rounding off a column/literal of
* type {@link com.salesforce.phoenix.schema.PDataType#TIMESTAMP}
* This class only supports rounding off the milliseconds that is for
* {@link TimeUnit#MILLISECOND}. If you want more options of rounding like
* using {@link TimeUnit#HOUR} use {@link RoundDateExpression}
*
* @author samarth.jain
* @since 3.0.0
*/
public class RoundTimestampExpression extends RoundDateExpression {
private static final long HALF_OF_NANOS_IN_MILLI = java.util.concurrent.TimeUnit.MILLISECONDS.toNanos(1)/2;
public RoundTimestampExpression() {}
private RoundTimestampExpression(List<Expression> children) {
super(children);
}
public static Expression create (List<Expression> children) throws SQLException {
Expression firstChild = children.get(0);
PDataType firstChildDataType = firstChild.getDataType();
String timeUnit = (String)((LiteralExpression)children.get(1)).getValue();
LiteralExpression multiplierExpr = (LiteralExpression)children.get(2);
/*
* When rounding off timestamp to milliseconds, nanos play a part only when the multiplier value
* is equal to 1. This is because for cases when multiplier value is greater than 1, number of nanos/multiplier
* will always be less than half the nanos in a millisecond.
*/
if((timeUnit == null || TimeUnit.MILLISECOND.toString().equalsIgnoreCase(timeUnit)) && ((Number)multiplierExpr.getValue()).intValue() == 1) {
return new RoundTimestampExpression(children);
}
// Coerce TIMESTAMP to DATE, as the nanos has no affect
List<Expression> newChildren = Lists.newArrayListWithExpectedSize(children.size());
newChildren.add(CoerceExpression.create(firstChild, firstChildDataType == PDataType.TIMESTAMP ? PDataType.DATE : PDataType.UNSIGNED_DATE));
newChildren.addAll(children.subList(1, children.size()));
return RoundDateExpression.create(newChildren);
}
@Override
protected PDataCodec getKeyRangeCodec(PDataType columnDataType) {
return columnDataType == PDataType.TIMESTAMP
? PDataType.DATE.getCodec()
: columnDataType == PDataType.UNSIGNED_TIMESTAMP
? PDataType.UNSIGNED_DATE.getCodec()
: super.getKeyRangeCodec(columnDataType);
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
if (children.get(0).evaluate(tuple, ptr)) {
ColumnModifier columnModifier = children.get(0).getColumnModifier();
PDataType dataType = getDataType();
int nanos = dataType.getNanos(ptr, columnModifier);
if(nanos >= HALF_OF_NANOS_IN_MILLI) {
long timeMillis = dataType.getMillis(ptr, columnModifier);
Timestamp roundedTs = new Timestamp(timeMillis + 1);
byte[] byteValue = dataType.toBytes(roundedTs);
ptr.set(byteValue);
}
return true; // for timestamp we only support rounding up the milliseconds.
}
return false;
}
}