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package net.sf.cuf.state.ui;

import net.sf.cuf.state.State;
import net.sf.cuf.state.AbstractState;

/**
 * AbstractSwingState has the common boiler plate code for the various
 * States in this package.
 * To avoid a "broadcast storm" of firing AbstractSwingState's, a
 * AbstractSwingState can be switched to "silent", in that case it
 * ignores all changes.
 */
public abstract class AbstractSwingState extends AbstractState implements State
{
    /** flag if we ignore all changes */
    protected boolean mSilent;

    /**
     * The constructor initializes some member variables.
     */
    public AbstractSwingState()
    {
        super();
        mSilent       = false;
        mIsInitialized= true;
    }

    /**
     * Checks the silent mode, returns true if we ignore a changing document.
     * @return true if we are in silent mode
     */
    public boolean isSilent()
    {
        return mSilent;
    }

    /**
     * Switches silent mode on or off. Switching silent mode off may trigger
     * an update if our current state is different from our document state.
     * @param pSilent true if we should ignore changes
     */
    public void setSilent(final boolean pSilent)
    {
        mSilent = pSilent;
        if (!mSilent)
        {
            checkStateChange();
        }
    }

    /**
     * Check if our monitored state changed, if it did fireStateChanged().
     */
    protected void checkStateChange()
    {
        if (mSilent)
        {
            return;
        }

        boolean selectionState= getInternalState();
        if (mIsEnabled != selectionState)
        {
            mIsEnabled= selectionState;
            setReason();
            try
            {
                fireStateChanged();
            }
            finally
            {
                mReason= null;
            }
        }
    }

    /**
     * Template method for the Strategy pattern: a derived class should
     * return the state of its state abstraction.
     * @return the current state
     */
    protected abstract boolean getInternalState();

    /**
     * Template method for the Strategy pattern: a derived class should set
     * mReason in this method.
     */
    protected abstract void setReason();
}