Cast_From_AkIntervalSeconds.java

/**
 * Copyright (C) 2009-2013 FoundationDB, LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.foundationdb.server.types.mcompat.mcasts;

import com.foundationdb.server.types.TCast;
import com.foundationdb.server.types.TCastBase;
import com.foundationdb.server.types.TExecutionContext;
import com.foundationdb.server.types.aksql.aktypes.AkInterval;
import com.foundationdb.server.types.mcompat.mtypes.MApproximateNumber;
import com.foundationdb.server.types.value.ValueSource;
import com.foundationdb.server.types.value.ValueTarget;

import java.util.EnumMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public final class Cast_From_AkIntervalSeconds {
    
    public static TCast TO_DOUBLE = new TCastBase(AkInterval.SECONDS, MApproximateNumber.DOUBLE) {
        @Override
        protected void doEvaluate(TExecutionContext context, ValueSource source, ValueTarget target) {
            long raw = source.getInt64();
            double result = 0;

            boolean isNegative;
            if (raw < 0) {
                isNegative = true;
                raw = -raw;
            }
            else {
                isNegative = false;
            }

            // we rely here on the fact that the EnumMap sorts entries by ordinal, _and_ that the ordinals
            // in TimeUnit are organized  by small unit -> big.
            for (Map.Entry<TimeUnit, Double> unitAndMultiplier : placeMultiplierMap.entrySet()) {
                TimeUnit unit = unitAndMultiplier.getKey();

                long asLong = AkInterval.secondsIntervalAs(raw, unit);
                assert (asLong >= 0) && (asLong < 100) : asLong;
                raw -= AkInterval.secondsRawFrom(asLong, unit);

                double multiplier = unitAndMultiplier.getValue();
                result += (multiplier * asLong);
            }

            if (isNegative)
                result *= -1d;

            target.putDouble(result);
        }
    };

    private static EnumMap<TimeUnit, Double> placeMultiplierMap = createPlaceMultiplierMap();

    private static EnumMap<TimeUnit, Double> createPlaceMultiplierMap() {
        // Desired result is something like 20120802120133.000000
        // Nicer format: yyyyMMddHHmmSS.uuuuuu 
        EnumMap<TimeUnit, Double> result = new EnumMap<>(TimeUnit.class);
        result.put(TimeUnit.MICROSECONDS, 1.0d/1000000.0d);
        result.put(TimeUnit.SECONDS,      1d);
        result.put(TimeUnit.MINUTES,    100d);
        result.put(TimeUnit.HOURS,    10000d);
        result.put(TimeUnit.DAYS,   1000000d);
        return result;
    }
}