Range class

Question

I just returned to Java after a year in Ruby.
Ruby had this handy loop for processing a range of numbers:
for i in 1..10 do /* handle i in here */ endSo I wrote a Range class. Now the equivalent java, very nearly as handy, is:
for (i: new Range(1,10) ) { /* handle i in here */ }No way to attach a file to these messages? Here's the code:
// \java\lib\Range.java
package library;
import java.util.Iterator;
/** Ruby: for i in 1..10 do ... end
* Java: for ( i : new Range(1,10) ) { ... }
* @author Martin Rinehart
public class Range implements Iterable<Integer> {
    private int first, last;
    public Range( int first, int last ) {
        this.first = first;
        this.last = last;
    /** iterator() is the entire Iterable interface.
     * @return An Iterator to iterate from first through last.
    public Iterator<Integer> iterator() {
        return new IRange( first, last );
} // end of class Range
/** An IRange is the Iterator that Range returns.
class IRange implements Iterator{
    private int first, last, pointer;
    /** Create a Range of ints between two integers.
     * @param first Starting value.
     * @param last Ending value (inclusive).
    public IRange( int first, int last ) {
        this.first = first;
        this.last = last;
        this.pointer = first;
    /** Part of the Iterator interface.
     * @return True until the end of the Range has been returned by next().
    public boolean hasNext() {
        boolean ret = pointer <= last;
        // Reached end? Reset for another iteration.
        if ( !ret ) pointer = first;
        return ret;
    /** Part of the Iterator interface.
     * @return The next element in the range.
    public Integer next() {
        Integer ret = new Integer( pointer );
        pointer++;
        return ret;
    /** Remove operation inappropriate for Range.
    public void remove() {
        throw new UnsupportedOperationException();
} // end of class IRange
// \java\lib\Range.java

Answer 1

MartinRinehart wrote:
How does making them final improve things?At the very least it documents intent. I would see Range as an immutable class and it makes sense to make that explicit.
Also, the JVM might be able to optimize a bit better if that information is available.
Why do you reject reuse. My first application for this wanted reusable ranges, so I added that little bit.I don't reject reusing the Range (i.e. the Iterable), that's already possible by calling iterator() twice. But you shouldn't reuse the Iterator.
An Iterator has a very specific life-cycle: It gets created, it iterates over its values, it returns false on hasNext() at some point (or throws a NoSuchElementException on next()) and from that point forward it will always return false on hasNext() (i.e. it is depleted).