How do I delete a KML Placemark from a Folder using the placemark's ID with the Java API for KML?

Question

I am using Java API for KML, JAK, to construct KML files. I would like to be able to delete a feature using its ID, but I have not found a good example of how to do so. Ideally, the code would be "myFolder.deleteFeatureById(theID);", but that is not the case. Is there any better method than the following?

List<Feature> features = myFolder.getFeature();
    for(int i=features.size()-1; i>=0; i--)
    {
        if(features.get(i).getId() == "myId")
        {
            features.remove(i);
            break;
        }
    }        

Answer 1

In Java you need to compare strings using String.equals() method not the logical == operator.

== checks if two things are EXACTLY the same thing, not if they have the same content so some string comparisons can be equal (same string) but test differently with == .

The following should work.

List<Feature> features = myFolder.getFeature();
for(int i=features.size()-1; i >= 0; i--)
{
    if("myId".equals(features.get(i).getId()))
    {
        features.remove(i);
        break;
    }
}

Here example code using JAK API that creates two placemarks in a folder then removes one by its id.

    final Kml kml = new Kml();
    final Folder folder = new Folder();
    kml.setFeature(folder);

    folder.setName("Folder.kml");
    folder.setOpen(true);

    final Placemark placemark1 = new Placemark().withId("1")
        .withName("Folder object 1 (Placemark)");
    folder.getFeature().add(placemark1);

    final Placemark placemark2 = new Placemark().withId("2")
        .withName("Folder object 2 (Placemark)");
    folder.getFeature().add(placemark2);

    List<Feature> features = folder.getFeature();
    System.out.println(features); // dumps two features     

    for(int i=features.size()-1; i >= 0; i--)
    {
        Feature f = features.get(i);
        if("1".equals(f.getId()))
        {
            // this removes feature with id = "1"
            features.remove(i);
            break;
        }
    }

    System.out.println(features); // folder now only has one item

Related details on this issue:

• http://www.javapractices.com/topic/TopicAction.do?Id=18
• https://softwareengineering.stackexchange.com/questions/193638/why-didnt-operator-string-value-comparison-make-it-to-java