be.error.rpi.adc.ObjectStatusReader.java Source code

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Here is the source code for be.error.rpi.adc.ObjectStatusReader.java

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/*-
 * #%L
 * Home Automation
 * %%
 * Copyright (C) 2016 - 2017 Koen Serneels
 * %%
 * 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.
 * #L%
 */
package be.error.rpi.adc;

import static be.error.rpi.adc.ObjectStatusTypeMapper.ObjectStatusType.READ_ERROR;
import static java.math.RoundingMode.HALF_UP;
import static java.util.BitSet.valueOf;
import static org.apache.commons.lang3.tuple.Pair.of;

import java.io.IOException;
import java.math.BigDecimal;
import java.util.BitSet;
import java.util.function.Function;

import org.apache.commons.lang3.tuple.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import be.error.rpi.adc.ObjectStatusTypeMapper.ObjectStatusType;

/**
 * @author Koen Serneels
 */
public class ObjectStatusReader implements Function<AdcChannel, Pair<AdcChannel, ObjectStatusType>> {

    private static final Logger logger = LoggerFactory.getLogger(ObjectStatusReader.class);

    private static final BigDecimal divider = new BigDecimal("2").pow(11);
    private static final BigDecimal step = new BigDecimal(5).divide(divider);

    private ObjectStatusTypeMapper objectStatusTypeMapper = new ObjectStatusTypeMapper();

    @Override
    public Pair<AdcChannel, ObjectStatusType> apply(final AdcChannel adcChannel) {
        try {
            byte readResult[] = adcChannel.getAdc().read(adcChannel);
            BitSet conversion = valueOf(new byte[] { readResult[1], readResult[0] });

            ObjectStatusType objectStatusType = READ_ERROR;

            if (!conversion.get(15)) {
                long[] l = conversion.toLongArray();
                if (l != null && l.length == 1) {
                    BigDecimal value = new BigDecimal(l[0]);
                    BigDecimal voltage = value.multiply(step).setScale(2, HALF_UP);
                    objectStatusType = objectStatusTypeMapper.map(voltage);
                }
            }
            return of(adcChannel, objectStatusType);
        } catch (IOException ioException) {
            logger.error("Could not read from channel", ioException);
            throw new RuntimeException(ioException);
        }
    }
}