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package net.sf.cuf.state;

/**
 * This class implements a MutableState and holds the necessary
 * state information inside the SimpleState object.

 */
public class SimpleState extends AbstractState implements MutableState
{
    /** Marker if we are in setEnabled(). */
    protected boolean mInSetEnabled;

    /**
     * The default constructor creates an uninitialized state,
     * which is not enabled. The state gets initialized as soon
     * as setEnabled() is called.
     */
    public SimpleState()
    {
        mInSetEnabled= false;
        resetIntern();
    }

    /**
     * Creates an initialized state.
     * @param pIsEnabled true if our state should be enabled
     */
    public SimpleState(final boolean pIsEnabled)
    {
        this();
        setEnabled(pIsEnabled);
    }

    /**
     * Sets the state.
     * @param pEnabled true if the state gets enabled
     */
    public void setEnabled(final boolean pEnabled)
    {
        setEnabled(pEnabled, null);
    }

    /**
     * Sets the state with a reason object. The reason object
     * may be null, and is returned to a getChangeReason() call
     * during the callback.
     * Only if the state change our listeners are notified.
     * @param pEnabled true if the state gets enabled
     * @param pReason null or reason for the change
     */
    public void setEnabled(final boolean pEnabled, final Object pReason)
    {
        // check if there is work to be done
        boolean changed= (!mIsInitialized) || (mIsEnabled!=pEnabled);
        if (changed)
        {
            mIsInitialized= true;
            mIsEnabled    = pEnabled;
            mReason       = pReason;
            mInSetEnabled = true;
            try
            {
                fireStateChanged();
            }
            finally
            {
                mReason      = null;
                mInSetEnabled= false;
            }
        }
    }

    /**
     * Marker method that indicates if the object is just firing a state change
     * due to a call of setEnabled().
     * This is useful for objects that are listeners to the State
     * and are not interested in state changes triggered by themselfs
     * calling setEnabled().
     * @return true if we during a state change due to setEnabled(), false otherwise.
     */
    protected boolean inSetEnabled()
    {
        return mInSetEnabled;
    }

    /**
     * Resets a MutableState to not initilized. Calling this
     * method will not trigger a notification of the
     * listeners.
     */
    public void reset()
    {
        resetIntern();
    }

    /**
     * small helper that does the "real" reset, also called from
     * the constructur.
     */
    private void resetIntern()
    {
        mIsInitialized= false;
        mIsEnabled    = false;
    }

}