Question

How do I solve this error? I tried just this, and (Article) this, and super.iterable(), but nothing seems to work. Only types of Article will ever be added to this queue. Java 1.7.0_03.

[javac] C:\cygwin\home\Chloe\Queue.java:26: error: incompatible types
[javac]             for (Article a: (Iterable) this) {
[javac]                             ^
[javac]   required: Article
[javac]   found:    Object

Here is the source code.

public class Queue<T> extends ArrayDeque {

public int words() {
    int words;
    for (Article a: (Iterable) this) {
    }
}
}

Answer 1

The iterator of your queue will return T Object instances, not Article. Your loop should go like this:

public int words() {
    int words;
    for (Object a: this) {
       // do something
    }
}

Or, if you need an article queue, declare the class this way:

public class Queue extends ArrayDeque<Article> {

  // this queue will store Article instances

}