// $Id: FigExtend.java,v 1.15 2004/08/12 19:50:11 mvw Exp $
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// software and its documentation without fee, and without a written
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package org.argouml.uml.diagram.use_case.ui;

import java.awt.Color;
import java.awt.Graphics;

import org.argouml.application.api.Notation;
import org.argouml.model.ModelFacade;
import org.argouml.uml.diagram.ui.FigEdgeModelElement;
import org.tigris.gef.base.PathConvPercent;
import org.tigris.gef.presentation.ArrowHeadGreater;
import org.tigris.gef.presentation.Fig;
import org.tigris.gef.presentation.FigGroup;
import org.tigris.gef.presentation.FigText;

import ru.novosoft.uml.MElementEvent;

/**
 * A fig for use with extend relationships on use case diagrams.

 *
 * Realised as a dotted line with an open arrow head and the label
 * «extend» together with any condition alongside.

 *
 * @author mail@jeremybennett.com
 */
public class FigExtend extends FigEdgeModelElement {

    /**
     * The «extend» label.

     */
    private FigText label;

    /**
     * The condition expression.

     */
    private FigText condition;

    /**
     * The group of label and condition.

     */
    private FigGroup fg;


    private ArrowHeadGreater endArrow = new ArrowHeadGreater();

    ///////////////////////////////////////////////////////////////////////////
    //
    // Constructors
    //
    ///////////////////////////////////////////////////////////////////////////

    /**
     * The default constructor, but should never be called directly
     * (use {@link #FigExtend(Object)}, since that sets the
     * owner. However we can't mark it as private, since GEF expects
     * to be able to call this when creating the diagram.

     */
    public FigExtend() {

        // We need a FigText to hold the <> label. Details are the
        // same as a stereotype, and we use the stereotype notation generator
        // to give us the text. When its all done, use calcBounds() to shrink
        // to size.

        label = new FigText(10, 30, 90, 20);

        label.setFont(getLabelFont());
        label.setTextColor(Color.black);
        label.setTextFilled(false);
        label.setFilled(false);
        label.setLineWidth(0);
        label.setExpandOnly(false);
        label.setMultiLine(false);
        label.setAllowsTab(false);
        label.setText("<>");
        

        label.calcBounds();

        // We need a FigText to hold the condition. At this stage we have
        // nothing to put in it (since we have no owner). Place it immediately
        // below the label, and with the same height and width.

        condition = new FigText(10, 30 + label.getBounds().height,
                                label.getBounds().width,
                                label.getBounds().height);

        condition.setFont(getLabelFont());
        condition.setTextColor(Color.black);
        condition.setTextFilled(false);
        condition.setFilled(false);
        condition.setLineWidth(0);
        condition.setExpandOnly(false);
        condition.setMultiLine(false);
        condition.setAllowsTab(false);

        // Join the two into a group

        fg = new FigGroup();

        fg.addFig(label);
        fg.addFig(condition);

        // Place in the middle of the line and ensure the line is dashed.  Add
        // an arrow with an open arrow head. Remember that for an extends
        // relationship, the arrow points to the base use case, but because of
        // the way we draw it, that is still the destination end.

        addPathItem(fg, new PathConvPercent(this, 50, 10));

        setDashed(true);

        setDestArrowHead(endArrow);

        // Make the edge go between nearest points

        setBetweenNearestPoints(true);
    }


    /**
     * The main constructor. Builds the FigEdge required and makes the
     * given edge object its owner.

     *
     * @param edge  The edge that will own the fig
     */
    public FigExtend(Object edge) {
        this();
        setOwner(edge);
    }


    ///////////////////////////////////////////////////////////////////////////
    //
    // Accessors
    //
    ///////////////////////////////////////////////////////////////////////////

    /**
     * Set a new fig to represent this edge.

     *
     * We invoke the superclass accessor. Then change aspects of the
     * new fig that are not as we want. In this case to use dashed
     * lines.

     *
     * @param f  The fig to use.
     */
    public void setFig(Fig f) {
        super.setFig(f);

        // Make sure the line is dashed

        setDashed(true);
    }

    /**
     * Define whether the given fig can be edited (it can't).

     *
     * @param f  The fig about which the enquiry is being made. Ignored in this
     *           implementation.
     *
     * @return   false under all circumstances.
     */
    protected boolean canEdit(Fig f) {
        return false;
    }


    ///////////////////////////////////////////////////////////////////////////
    //
    // Event handlers
    //
    ///////////////////////////////////////////////////////////////////////////

    /**
     * This is called after any part of the UML MModelElement has
     * changed. This method automatically updates things specific to
     * this fig. Subclasses should override and update other parts.

     *
     * We reset the condition text. We really ought to check that
     * there has actually been a change, but for now we do it every
     * time.

     *
     * @see org.argouml.uml.diagram.ui.FigEdgeModelElement#modelChanged(ru.novosoft.uml.MElementEvent)
     */
    protected void modelChanged(MElementEvent e) {

        // Give up if we have no owner

        Object extend = /*(MExtend)*/ getOwner();

        if (extend == null) {
            return;
        }
        
        // Let the superclass sort itself out, and then tell GEF we are going
        // to start something

        super.modelChanged(e);

        // Now sort out the condition text. Use the null string if there is no
        // condition set. We call the main generate method, which will realise
        // this is a MExpression (subclass) and invoke the correct method.

        Object/*MBooleanExpression*/ c =
	    ModelFacade.getCondition(extend);

        if (c == null) {
            condition.setText("");
        }
        else {
            condition.setText(Notation.generate(this, c));
        }
        

        // Let the group recalculate its bounds and then tell GEF we've
        // finished.

        fg.calcBounds();
        endTrans();
    }

    /**
     * @see org.tigris.gef.presentation.Fig#paint(java.awt.Graphics)
     */
    public void paint(Graphics g) {
        endArrow.setLineColor(getLineColor());
        super.paint(g);
    }
    

} /* end class FigExtend */