Java Iterator contract seems to be broken in Aspose Slides collections

Aspose.Slides Product Family
1

Hello,

like in

I think I have found that the Aspose Slides for Java API breaks the contract for java.util.Iterator in the implemantation of com.aspose.slides.ISlideCollection and com.aspose.slides.IShapeCollection.

The call to .hasNext() has the side effect to progress the iterator one step further.
That should be the job of .next(), which .next() does not perform. .nect() seems to have has no sideeffects.

A call to .next() with no prior .hasNext() always returns null, even for filled collections. Which is also not as expected.

I found that behavior in Version 19.1 and 20.4.

I have some example code to demonstrate this:

  // //////////////////////////////////////////////////////////////////////////////////////////////////

    package de.demo;

    import java.util.Iterator;
    import com.aspose.slides.*;


    public class App
    {
        public static void main( String[] args )
        {
           IPresentation presentation = new Presentation("folienpool.pptx");
        System.out.println("First slides:");

        ISlideCollection slides = presentation.getSlides();
        Iterator<ISlide>  slides_iter;

        slides_iter= slides.iterator();

        System.out.println("1. Slides: .next()-> " + slides_iter.next());

        slides_iter = slides.iterator();
        slides_iter.hasNext();
        System.out.println("2. Slides: .hasNext() .next()-> " + slides_iter.next());

        slides_iter = slides.iterator();
        slides_iter.hasNext();
        System.out.println("3. Slides: .hasNext() .next()-> " + slides_iter.next());

        slides_iter = slides.iterator();
        slides_iter.hasNext();
        slides_iter.hasNext();
        System.out.println("4. Slides: .hasNext() : .hasNext() .next()-> " + slides_iter.next());

        slides_iter = slides.iterator();
        slides_iter.hasNext();
        slides_iter.next();
        System.out.println("5. Slides: .hasNext() .next() .next() -> " + slides_iter.next());

        System.out.println("Now Shapes:");

        ISlide slide = slides.get_Item(31);
        IShapeCollection shapes = slide.getShapes();
        Iterator<IShape>  shape_iter;

        shape_iter= shapes.iterator();

        System.out.println("6. Shapes: .next() -> " + shape_iter.next());

        shape_iter = shapes.iterator();
        shape_iter.hasNext();
        System.out.println("7. Shapes: .hasNext() .next() -> " + shape_iter.next());

        shape_iter = shapes.iterator();
        shape_iter.hasNext();
        System.out.println("8. Shapes: .hasNext() .next() -> " + shape_iter.next());

        shape_iter = shapes.iterator();
        shape_iter.hasNext();
        shape_iter.hasNext();
        System.out.println("9. Shapes: .hasNext() .hasNext() .next() -> " + shape_iter.next());

        shape_iter = shapes.iterator();
        shape_iter.hasNext();
        shape_iter.next();
        System.out.println("10. Shapes: .hasNext() .next() .next() -> " + shape_iter.next());

    }
}

// //////////////////////////////////////////////////////////////////////////////////////////////////

Example output:

First slides:

  1. Slides: .next()-> null
  2. Slides: .hasNext() .next()-> com.aspose.slides.Slide@27210a3b
  3. Slides: .hasNext() .next()-> com.aspose.slides.Slide@27210a3b
  4. Slides: .hasNext() : .hasNext() .next()-> com.aspose.slides.Slide@3a12f3e7
  5. Slides: .hasNext() .next() .next() → com.aspose.slides.Slide@27210a3b
    Now Shapes:
  6. Shapes: .next() → null
  7. Shapes: .hasNext() .next() → com.aspose.slides.Table@84a9f65
  8. Shapes: .hasNext() .next() → com.aspose.slides.Table@84a9f65
  9. Shapes: .hasNext() .hasNext() .next() → com.aspose.slides.AutoShape@70700b8a
  10. Shapes: .hasNext() .next() .next() → com.aspose.slides.Table@84a9f65

Expectation:

What I would expect for slides is:
1 = 2 = 3 = 4 = com.aspose.slides.Slide@27210a3b

and

5 = com.aspose.slides.Slide@3a12f3e7

And for shapes:
6 = 7= 8 = 9 = com.aspose.slides.Table@84a9f65
and
10 = com.aspose.slides.AutoShape@70700b8a

Kind regards,

Uwe Hubert

2

@uhubert,

I have observed the issue shared by you and request you to please share the source file that you have used on your end too so that I may log issue.

3

The operating system is Linux Ubuntu 20.04 LTS.

java -version
openjdk version “1.8.0_252”
OpenJDK Runtime Environment (build 1.8.0_252-8u252-b09-1ubuntu1-b09)
OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)

App.zip (587 Bytes)

4

@uhubert,

I have observed the sample code but it is still missing the source file used to reproduce the issue.Please share the requested information

5

When you mean with “source file” the .pptx slides file, here it is.folienpool.zip (33.7 KB)

The Java source file is in the App.zip attachment of my last response.

6

@uhubert,

I have observed the issue shared and have created a ticket with ID SLIDESJAVA-38108 in our issue tracking system to further investigate and resolve the issue. This thread has been linked with the issue so that you may be notified once the issue will be fixed.

7

@uhubert,

In upcoming Aspose.Slides for Java 20.6 and onward versions, we have introduced the support for method iteratorJava() in many different IGenericCollection interface and several collection classes.

The iteratorJava() method returns iterator that is fully complies with the Java Iterator logic.

slides_iter= slides.iteratorJava(); 
System.out.println("1. Slides: .next()-> " + slides_iter.next()); 
slides_iter = slides.iteratorJava(); 
slides_iter.hasNext(); 
System.out.println("2. Slides: .hasNext() .next()-> " + slides_iter.next()); 

shape_iter= shapes.iteratorJava(); 
System.out.println("6. Shapes: .next() -> " + shape_iter.next()); 
shape_iter = shapes.iteratorJava(); 
shape_iter.hasNext(); System.out.println("7. Shapes: .hasNext() .next() -> " + shape_iter.next());
8

The issues you have found earlier (filed as SLIDESJAVA-38108) have been fixed in this update.