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copied!<p>java.awt.geom.Area can combine multiple shapes with methods add, subtract, exclusiveOr, and intersect. It's a ready-made class for CompositeShape.</p> <p>It seems extremely weird that you've been asked to recreate it as "CompositeShape", because Area already does what you want.</p> <p>The solution could be as simple as </p> <p>class CompositeShape extends java.awt.geom.Area {}</p> <p>and you're done.</p> <p><strong>Or</strong>, the fact that you've been given a hint about PathIterator, it might be that you're being encouraged to manage the added shapes in a list manually, then implement all the methods of the Shape interface in terms of iterating over the other shapes.</p> <p>E.g., getBounds() needs to return the rectangular bounds of the shape, so get the rectangular bounds of the first, then use Rectangle.union to join it with the bounds of the others.</p> <p>And for getPathIterator(), return a new inner class implementing PathIterator that will iterate over all the shapes in your collection, and iterate the path segments of each of their getPathIterator methods, returning each path segment.</p> <p>It all sounds unnecessary in practice, since the needed class already exists. I think you should get clarification on what is wanted. Good luck.</p> <hr> <p>To clarify what I said about the implementation of getPathIterator, return something like this. I didn't test this. This assumes your list is called <code>shapes</code>.</p> <pre><code>public PathIterator getPathIterator(final AffineTransform at, final double flatness) { return new PathIterator() { private PathIterator currentPathIterator; private Iterator<Shape> shapeIterator = shapes.iterator(); { nextShape(); } private void nextShape() { if (shapeIterator.hasNext()) { currentPathIterator = shapeIterator.next().getPathIterator(at, flatness); } else { currentPathIterator = null; } } public int getWindingRule() { return WIND_NON_ZERO; } public boolean isDone() { for (;;) { if (currentPathIterator == null) return true; if (!currentPathIterator.isDone()) return false; nextShape(); } } public void next() { currentPathIterator.next(); } public int currentSegment(float[] coords) { return currentPathIterator.currentSegment(coords); } public int currentSegment(double[] coords) { return currentPathIterator.currentSegment(coords); } }; } </code></pre>

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