/*
* Licensed to CRATE Technology GmbH ("Crate") under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership. Crate licenses
* this file to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License. You may
* obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
* However, if you have executed another commercial license agreement
* with Crate these terms will supersede the license and you may use the
* software solely pursuant to the terms of the relevant commercial agreement.
*/
package io.crate.operation.aggregation.impl;
import com.google.common.collect.ImmutableList;
import io.crate.metadata.FunctionIdent;
import io.crate.metadata.FunctionInfo;
import io.crate.operation.Input;
import io.crate.operation.aggregation.AggregationFunction;
import io.crate.operation.aggregation.AggregationState;
import io.crate.types.DataType;
import io.crate.types.DataTypes;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import java.io.IOException;
public abstract class MinimumAggregation extends AggregationFunction<MinimumAggregation.MinimumAggState> {
public static final String NAME = "min";
private final FunctionInfo info;
public static void register(AggregationImplModule mod) {
for (final DataType dataType : DataTypes.PRIMITIVE_TYPES) {
mod.register(
new MinimumAggregation(
new FunctionInfo(new FunctionIdent(NAME,
ImmutableList.of(dataType)), dataType, FunctionInfo.Type.AGGREGATE)
) {
@Override
public MinimumAggState newState() {
return new MinimumAggState() {
@Override
public void readFrom(StreamInput in) throws IOException {
if (!in.readBoolean()) {
setValue((Comparable) dataType.streamer().readValueFrom(in));
}
}
@Override
public void writeTo(StreamOutput out) throws IOException {
Object value = value();
out.writeBoolean(value == null);
if (value != null) {
dataType.streamer().writeValueTo(out, value);
}
}
};
}
}
);
}
}
MinimumAggregation(FunctionInfo info) {
this.info = info;
}
@Override
public FunctionInfo info() {
return info;
}
@Override
public boolean iterate(MinimumAggState state, Input... args) {
Object value = args[0].value();
assert value == null || value instanceof Comparable;
state.add((Comparable) value);
return true;
}
public static abstract class MinimumAggState extends AggregationState<MinimumAggState> {
private Comparable value = null;
@Override
public Object value() {
return value;
}
@Override
public void reduce(MinimumAggState other) {
if (other.value() == null) {
return;
} else if (value() == null) {
value = other.value;
return;
}
if (compareTo(other) > 0) {
value = other.value;
}
}
void add(Comparable otherValue) {
if (otherValue == null) {
return;
} else if (value() == null) {
value = otherValue;
return;
}
if (compareValue(otherValue) > 0) {
value = otherValue;
}
}
public void setValue(Comparable value) {
this.value = value;
}
@Override
public int compareTo(MinimumAggState o) {
if (o == null) return -1;
return compareValue(o.value);
}
public int compareValue(Comparable otherValue) {
if (value == null) return (otherValue == null ? 0 : 1);
if (otherValue == null) return -1;
return value.compareTo(otherValue);
}
@Override
public String toString() {
return "<MinimumAggState \"" + value + "\"";
}
}
}