package de.intevation.flys.artifacts.states;

import org.apache.log4j.Logger;

import de.intevation.artifacts.Artifact;
import de.intevation.artifacts.CallContext;

import de.intevation.artifactdatabase.data.StateData;

import de.intevation.flys.artifacts.FLYSArtifact;


/**
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public abstract class RangeState extends DefaultState {

    /** The logger that is used in this class.*/
    private Logger logger = Logger.getLogger(RangeState.class);


    public RangeState() {
    }


    protected abstract String   getLowerField();
    protected abstract String   getUpperField();
    protected abstract String   getStepField();
    protected abstract double[] getMinMax(Artifact artifact);


    /**
     * Validates a given range with a given valid range.
     *
     * @param fromValid Valid lower value of the range.
     * @param toValid Valid upper value of the range.
     * @param from The lower value.
     * @param to The upper value.
     * @param step The step width.
     *
     * @return true, if everything was fine, otherwise an exception is thrown.
     */
    protected boolean validateBounds(
        double fromValid, double toValid,
        double from,      double to,      double step)
    throws IllegalArgumentException
    {
        logger.debug("RangeState.validateRange");

        if (from < fromValid) {
            logger.error(
                "Invalid 'from'. " + from + " is smaller than " + fromValid);
            throw new IllegalArgumentException("error_feed_from_out_of_range");
        }
        else if (to > toValid) {
            logger.error(
                "Invalid 'to'. " + to + " is bigger than " + toValid);
            throw new IllegalArgumentException("error_feed_to_out_of_range");
        }

        return true;
    }


    @Override
    public boolean validate(Artifact artifact, CallContext context)
    throws IllegalArgumentException
    {
        FLYSArtifact flys = (FLYSArtifact) artifact;

        StateData dFrom = getData(flys, getLowerField());
        StateData dTo   = getData(flys, getUpperField());
        StateData dStep = getData(flys, getStepField());

        String fromStr = dFrom != null ? (String) dFrom.getValue() : null;
        String toStr   = dTo   != null ? (String) dTo.getValue()   : null;
        String stepStr = dStep != null ? (String) dStep.getValue() : null;

        if (fromStr == null || toStr == null || stepStr == null) {
            throw new IllegalArgumentException("error_empty_state");
        }

        try {
            double from = Double.parseDouble(fromStr);
            double to   = Double.parseDouble(toStr);
            double step = Double.parseDouble(stepStr);

            double[] minmax = getMinMax(flys);

            return validateBounds(minmax[0], minmax[1], from, to, step);
        }
        catch (NumberFormatException nfe) {
            throw new IllegalArgumentException("error_invalid_double_value");
        }
    }
}
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