package org.osgl.util;
import org.osgl.$;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/**
* Created with IntelliJ IDEA.
* User: luog
* Date: 10/11/13
* Time: 9:55 PM
* To change this template use File | Settings | File Templates.
*/
public class ZippedListIterator<A, B> implements ListIterator<$.T2<A, B>> {
private ListIterator<A> a;
private ListIterator<B> b;
private $.Option<A> defA = $.none();
private $.Option<B> defB = $.none();
ZippedListIterator(ListIterator<A> a, ListIterator<B> b) {
E.NPE(a, b);
this.a = a;
this.b = b;
}
ZippedListIterator(ListIterator<A> a, ListIterator<B> b, A defA, B defB) {
this(a, b);
this.defA = $.some(defA);
this.defB = $.some(defB);
}
@Override
public boolean hasNext() {
boolean hasA = a.hasNext(), hasB = b.hasNext();
if (hasA && hasB) {
return true;
}
if (defA.isDefined()) {
return hasA || hasB;
} else {
return false;
}
}
@Override
public boolean hasPrevious() {
boolean hasA = a.hasPrevious(), hasB = b.hasPrevious();
if (hasA && hasB) {
return true;
}
if (defA.isDefined()) {
return hasA || hasB;
} else {
return false;
}
}
@Override
public $.T2<A, B> next() {
boolean hasA = a.hasNext(), hasB = b.hasNext();
if (hasA && hasB) {
return $.T2(a.next(), b.next());
}
if (defA.isDefined()) {
if (hasA) {
return $.T2(a.next(), defB.get());
} else if (hasB) {
return $.T2(defA.get(), b.next());
} else {
throw new NoSuchElementException();
}
} else {
throw new NoSuchElementException();
}
}
@Override
public $.T2<A, B> previous() {
boolean hasA = a.hasPrevious(), hasB = b.hasPrevious();
if (hasA && hasB) {
return $.T2(a.previous(), b.previous());
}
if (defA.isDefined()) {
if (hasA) {
return $.T2(a.previous(), defB.get());
} else if (hasB) {
return $.T2(defA.get(), b.previous());
} else {
throw new NoSuchElementException();
}
} else {
throw new NoSuchElementException();
}
}
@Override
public int nextIndex() {
int idA = a.nextIndex(), idB = b.nextIndex();
if (defA.isDefined()) {
return Math.max(idA, idB);
} else {
return Math.min(idA, idB);
}
}
@Override
public int previousIndex() {
int idA = a.previousIndex(), idB = b.previousIndex();
if (defA.isDefined()) {
return Math.max(idA, idB);
} else {
return Math.min(idA, idB);
}
}
@Override
public void set($.T2<A, B> abt2) {
throw new UnsupportedOperationException();
}
@Override
public void add($.T2<A, B> abt2) {
throw new UnsupportedOperationException();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}