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package net.sf.cuf.model.ui;

import net.sf.cuf.model.ValueModel;

import javax.swing.ButtonModel;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;

/**
 * A ButtonModelAdapter connects the state of a ValueModel to the
 * selection state of a ButtonModel. Whenever one of the model
 * changes, the other is adjusted accordingly.
 * A ButtonModelAdapter is itself not a ValueModel, but connects a
 * ValueModel to a ButtonModel.
 * The ValueModel should hold a Boolean, at least this adapter will
 * write a Boolean to the ValueModel.
 */
public class ButtonModelAdapter implements ChangeListener
{
    /** the value model we adapt to, never null */
    private ValueModel       mValueModel;
    /** the button model we adapt to, never null */
    private ButtonModel         mButtonModel;
    /** last state of our button model */
    private boolean             mWasSelected;
    /** marker if we are in stateChange */
    private boolean             mInStateChanged;
    /** marker if we have inverted logic */
    private boolean             mInvert;


    /**
     * Creates a new adapter between a ValueModel and a ButtonModel .
     * Whenever one of the models changes, the other is adjusted accordingly.
     * The initial selection state is taken from the value model.
     * @param pValueModel the value model
     * @param pButtonModel the button model
     */
    public ButtonModelAdapter(final ValueModel pValueModel, final ButtonModel pButtonModel)
    {
        this(pValueModel, pButtonModel, false);
    }

    /**
     * Creates a new adapter between a ValueModel and a ButtonModel .
     * Whenever one of the models changes, the other is adjusted accordingly.
     * The initial selection state is taken from the value model.
     * @param pValueModel the value model
     * @param pButtonModel the button model
     * @param pInvert if true, we use inverted logic
     */
    public ButtonModelAdapter(final ValueModel pValueModel,
                              final ButtonModel pButtonModel,
                              final boolean pInvert)
    {
        if (pValueModel==null)
            throw new IllegalArgumentException("value model must not be null");
        if (pButtonModel==null)
            throw new IllegalArgumentException("button model must not be null");

        mValueModel = pValueModel;
        mButtonModel= pButtonModel;
        mInvert     = pInvert;
        mButtonModel.setSelected(isValueModelSelected());
        mWasSelected   = mButtonModel.isSelected();
        mInStateChanged= false;
        mButtonModel.addChangeListener(this);
        mValueModel. addChangeListener(this);
    }

    /**
     * Invoked when either the value model or the button model changed its state.
     *
     * @param pEvent  a ChangeEvent object
     */
    public void stateChanged(final ChangeEvent pEvent)
    {
        if (mInStateChanged)
        {
            return;
        }

        mInStateChanged= true;
        try
        {
            Object source= pEvent.getSource();
            //noinspection ObjectEquality
            if (source == mValueModel)
            {
                // ValueModel callback
                boolean isSelected= isValueModelSelected();
                mButtonModel.setSelected(isSelected);
                mWasSelected= isSelected;
            }
            else //noinspection ObjectEquality
                if (source== mButtonModel)
            {
                // ButtonModel callback
                boolean isSelected = isButtonModelSelected();
                if (isSelected!=mWasSelected)
                {
                    mValueModel.setValue(isSelected);
                    mWasSelected= isSelected;
                }
            }
            else
            {
                // should never happen
                throw new IllegalStateException("stateChanged with wrong source"+source);
            }
        }
        finally
        {
            mInStateChanged= false;
        }
    }

    /**
     * Helper to extract the boolean from our ButtonModel.
     * @return true if the ButtonModel is true and mInvert is false
     */
    private boolean isButtonModelSelected()
    {
        boolean isSelected= mButtonModel.isSelected();
        if (mInvert)
        {
            isSelected= !isSelected;
        }
        return isSelected;
    }

    /**
     * Helper to extract the boolean from our ValueModel.
     * @return true if the ValueModel contains "true" or Boolean.TRUE and mInvert is false
     */
    private boolean isValueModelSelected()
    {
        boolean isSelected= mValueModel.booleanValue();
        if (mInvert)
        {
            isSelected= !isSelected;
        }
        return isSelected;
    }
}