package org.dcache.services.info.base;

/**
 * The StringStateValue Class allows String values to be stored within dCache's State.
 * @author Paul Millar <paul.millar@desy.de>
 */
public class StringStateValue extends StateValue
{
    private final String _storage;
    private static final int NULL_HASH_CODE = 0xdeadbeaf;

    /**
     * Create a new Ephemeral String StateValue
     * @param value the String to be stored.
     */
    public StringStateValue(String value)
    {
        this(value, false);
    }

    /**
     * Create a String StateValue that is either immortal or ephermal.
     * @param value the String value to store
     * @param isImmortal true if the value is immortal, false otherwise
     */
    public StringStateValue(String value, boolean isImmortal)
    {
        super(isImmortal);
        _storage = value;
    }

    /**
     * Create an expiring String StateValue.
     * @param value the String to store.
     * @param duration the duration, in seconds, this should be maintained within dCache state.
     */
    public StringStateValue(String value, long duration)
    {
        super(duration);
        _storage = value;
    }

    public String getValue()
    {
        return _storage;
    }

    @Override
    public String toString()
    {
        return _storage != null ? _storage : "(null)";
    }

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


    /**
     * Needed for the Visitor pattern.  See StateVisitor interface for more details.
     */
    @Override
    public void acceptVisitor(StatePath path, StateVisitor visitor)
    {
        visitor.visitString(path, this);
    }

    /**
     * Override the default hashCode to honour the hashCode() equals() contract.
     */
    @Override
    public int hashCode()
    {
        return _storage == null ? NULL_HASH_CODE : _storage.hashCode();
    }

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

        StringStateValue otherValue = (StringStateValue) other;

        if (_storage == null) {
            return otherValue._storage == null;
        }

        return _storage.equals(otherValue._storage);
    }
}