public static Enumerable groupJoin()

in src/main/java/net/hydromatic/linq4j/EnumerableDefaults.java [725:758]

• 30 lines of code
• 2 McCabe index (conditional complexity)

  public static <TSource, TInner, TKey, TResult> Enumerable<TResult> groupJoin(
      final Enumerable<TSource> outer, final Enumerable<TInner> inner,
      final Function1<TSource, TKey> outerKeySelector,
      final Function1<TInner, TKey> innerKeySelector,
      final Function2<TSource, Enumerable<TInner>, TResult> resultSelector) {
    return new AbstractEnumerable<TResult>() {
      final Map<TKey, TSource> outerMap = outer.toMap(outerKeySelector);
      final Lookup<TKey, TInner> innerLookup = inner.toLookup(innerKeySelector);
      final Enumerator<Map.Entry<TKey, TSource>> entries =
          Linq4j.enumerator(outerMap.entrySet());

      public Enumerator<TResult> enumerator() {
        return new Enumerator<TResult>() {
          public TResult current() {
            final Map.Entry<TKey, TSource> entry = entries.current();
            final Enumerable<TInner> inners = innerLookup.get(entry.getKey());
            return resultSelector.apply(entry.getValue(),
                inners == null ? Linq4j.<TInner>emptyEnumerable() : inners);
          }

          public boolean moveNext() {
            return entries.moveNext();
          }

          public void reset() {
            entries.reset();
          }

          public void close() {
          }
        };
      }
    };
  }