de.qaware.chronix.solr.query.analysis.functions.aggregations.First.java Source code

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Here is the source code for de.qaware.chronix.solr.query.analysis.functions.aggregations.First.java

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/*
 * Copyright (C) 2016 QAware GmbH
 *
 *    Licensed 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.
 */
package de.qaware.chronix.solr.query.analysis.functions.aggregations;

import de.qaware.chronix.solr.query.analysis.functions.ChronixAggregation;
import de.qaware.chronix.solr.query.analysis.functions.FunctionType;
import de.qaware.chronix.timeseries.MetricTimeSeries;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;

/**
 * @author f.lautenschlager
 */
public final class First implements ChronixAggregation<MetricTimeSeries> {

    /**
     * Gets the first value in the time series.
     * It first orders the time series.
     *
     * @param args the time series
     * @return the average or 0 if the list is empty
     */
    @Override
    public double execute(MetricTimeSeries... args) {

        //Sum needs at least one time series
        if (args.length < 1) {
            throw new IllegalArgumentException("First function needs at least one time series");
        }
        //Took the first time series
        MetricTimeSeries timeSeries = args[0];

        //If it is empty, we return NaN
        if (timeSeries.size() <= 0) {
            return Double.NaN;
        }

        //we need to sort the time series
        timeSeries.sort();
        return timeSeries.getValue(0);
    }

    @Override
    public String[] getArguments() {
        return new String[0];
    }

    @Override
    public FunctionType getType() {
        return FunctionType.FIRST;
    }

    @Override
    public boolean needSubquery() {
        return false;
    }

    @Override
    public String getSubquery() {
        return null;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        if (obj.getClass() != getClass()) {
            return false;
        }
        return new EqualsBuilder().isEquals();
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder().toHashCode();
    }
}