/*
* Druid - a distributed column store.
* Copyright (C) 2012, 2013 Metamarkets Group Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package io.druid.query.groupby.orderby;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Charsets;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.metamx.common.IAE;
import com.metamx.common.ISE;
import javax.annotation.Nullable;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
/**
*/
public class OrderByColumnSpec
{
public static enum Direction
{
ASCENDING,
DESCENDING
}
/**
* Maintain a map of the enum values so that we can just do a lookup and get a null if it doesn't exist instead
* of an exception thrown.
*/
private static final Map<String, Direction> stupidEnumMap;
static {
final ImmutableMap.Builder<String, Direction> bob = ImmutableMap.builder();
for (Direction direction : Direction.values()) {
bob.put(direction.toString(), direction);
}
stupidEnumMap = bob.build();
}
private final String dimension;
private final Direction direction;
@JsonCreator
public static OrderByColumnSpec create(Object obj)
{
Preconditions.checkNotNull(obj, "Cannot build an OrderByColumnSpec from a null object.");
if (obj instanceof String) {
return new OrderByColumnSpec(obj.toString(), null);
} else if (obj instanceof Map) {
final Map map = (Map) obj;
final String dimension = map.get("dimension").toString();
final Direction direction = determineDirection(map.get("direction"));
return new OrderByColumnSpec(dimension, direction);
} else {
throw new ISE("Cannot build an OrderByColumnSpec from a %s", obj.getClass());
}
}
public static OrderByColumnSpec asc(String dimension)
{
return new OrderByColumnSpec(dimension, Direction.ASCENDING);
}
public static List<OrderByColumnSpec> ascending(String... dimension)
{
return Lists.transform(
Arrays.asList(dimension),
new Function<String, OrderByColumnSpec>()
{
@Override
public OrderByColumnSpec apply(@Nullable String input)
{
return asc(input);
}
}
);
}
public static OrderByColumnSpec desc(String dimension)
{
return new OrderByColumnSpec(dimension, Direction.DESCENDING);
}
public static List<OrderByColumnSpec> descending(String... dimension)
{
return Lists.transform(
Arrays.asList(dimension),
new Function<String, OrderByColumnSpec>()
{
@Override
public OrderByColumnSpec apply(@Nullable String input)
{
return desc(input);
}
}
);
}
public OrderByColumnSpec(
String dimension,
Direction direction
)
{
this.dimension = dimension;
this.direction = direction == null ? Direction.ASCENDING : direction;
}
@JsonProperty
public String getDimension()
{
return dimension;
}
@JsonProperty
public Direction getDirection()
{
return direction;
}
public static Direction determineDirection(Object directionObj)
{
if (directionObj == null) {
return null;
}
String directionString = directionObj.toString();
Direction direction = stupidEnumMap.get(directionString);
if (direction == null) {
final String lowerDimension = directionString.toLowerCase();
for (Direction dir : Direction.values()) {
if (dir.toString().toLowerCase().startsWith(lowerDimension)) {
if (direction != null) {
throw new ISE("Ambiguous directions[%s] and [%s]", direction, dir);
}
direction = dir;
}
}
}
if (direction == null) {
throw new IAE("Unknown direction[%s]", directionString);
}
return direction;
}
@Override
public String toString()
{
return "OrderByColumnSpec{" +
"dimension='" + dimension + '\'' +
", direction=" + direction +
'}';
}
public byte[] getCacheKey()
{
final byte[] dimensionBytes = dimension.getBytes(Charsets.UTF_8);
final byte[] directionBytes = direction.name().getBytes(Charsets.UTF_8);
return ByteBuffer.allocate(dimensionBytes.length + directionBytes.length)
.put(dimensionBytes)
.put(directionBytes)
.array();
}
}