package org.dcache.services.info.base;


/**
 * Extends the abstract StateValue to allow storing Floating-point numbers
 * within the dCache state tree.
 *
 * @author Paul Millar <paul.millar@desy.de>
 */
public class FloatingPointStateValue extends StateValue
{
    private final double _storage;

    /**
     * Create a new Ephemeral FloatingPoint StateValue that will store
     * a floating-point number.  This metric has no life-time.
     * @param value the value to be stored.
     */
    public FloatingPointStateValue(double value)
    {
        this(value, false);
    }


    /**
     * Create a new FloatingPoint StateValue that is either Immortal or Ephemeral.
     * @param value the floating-point number to store.
     * @param isImmortal true if this is immortal, otherwise ephemeral.
     */
    public FloatingPointStateValue(double value, boolean isImmortal)
    {
        super(isImmortal);
        _storage = value;
    }

    /**
     * Create a new FloatingPointStateValue that will store
     * a floating-point number within the dCache state tree.
     * This metric will last for the specified duration before
     * being flushed from the state.
     * @param value the value to be stored
     * @param duration the lifetime, in seconds, for this metric.
     */
    public FloatingPointStateValue(double value, long duration)
    {
        super(duration);
        _storage = value;
    }

    @Override
    public String getTypeName()
    {
        return "float";
    }

    @Override
    public String toString()
    {
        return Double.toString(_storage);
    }

    public double getValue()
    {
        return _storage;
    }

    /**
     *  Leaf-node specific support for the Visitor pattern.  See StateValue for inherited
     *  actual implementation and StateVisitor interface for more details.
     */
    @Override
    public void acceptVisitor(StatePath path, StateVisitor visitor)
    {
        visitor.visitFloatingPoint(path, this);
    }

    /**
     *  Override the default hashCode() method, to honour the hashCode() / equals() contract.
     */
    @Override
    public int hashCode()
    {
        // TODO: do something better here.
        Float floatVal = new Float(_storage);
        return floatVal.hashCode();
    }


    /**
     *  Override the default equals() method.
     */
    @Override
    public boolean equals(Object other)
    {
        if (!(other instanceof FloatingPointStateValue)) {
            return false;
        }

        FloatingPointStateValue otherValue = (FloatingPointStateValue) other;

        return _storage == otherValue._storage;
    }
}