TranslatingSequence.java

package jetbrains.mps.internal.collections.runtime.impl;

/*Generated by MPS */

import jetbrains.mps.baseLanguage.closures.runtime._FunctionTypes;
import java.util.Iterator;
import java.util.NoSuchElementException;
import jetbrains.mps.internal.collections.runtime.Sequence;
import jetbrains.mps.internal.collections.runtime.StopIteratingException;

public class TranslatingSequence<U, V> extends AbstractChainedSequence<U, V> implements Iterable<V> {
  private final _FunctionTypes._return_P1_E0<? extends Iterable<V>, ? super U> translator;
  public TranslatingSequence(Iterable<U> input, _FunctionTypes._return_P1_E0<? extends Iterable<V>, ? super U> translator) {
    super(input);
    if (translator == null) {
      throw new NullPointerException();
    }
    this.translator = translator;
  }
  @Override
  public Iterator<V> iterator() {
    return new TranslatingSequence.TranslatingIterator();
  }
  private class TranslatingIterator implements Iterator<V> {
    private Iterator<U> inputIt;
    private Iterator<V> transIt;
    private HasNextState hasNext = HasNextState.UNKNOWN;
    private V next;
    private TranslatingIterator() {
    }
    @Override
    public boolean hasNext() {
      if (inputIt == null) {
        init();
      }
      if (hasNext.unknown()) {
        moveToNext();
      }
      return hasNext.hasNext();
    }
    @Override
    public V next() {
      if (inputIt == null) {
        init();
      }
      if (hasNext.unknown()) {
        moveToNext();
      }
      if (!((hasNext.hasNext()))) {
        throw new NoSuchElementException();
      }
      return clearNext();
    }
    @Override
    public void remove() {
      throw new UnsupportedOperationException();
    }
    private void init() {
      inputIt = getInput().iterator();
    }
    private void moveToNext() {
      hasNext = HasNextState.AT_END;
      next = null;
      do {
        try {
          if (transIt != null && transIt.hasNext()) {
            V tmp = transIt.next();
            if (Sequence.IGNORE_NULL_VALUES) {
              if (tmp == null) {
                continue;
              }
            }
            next = tmp;
            hasNext = HasNextState.HAS_NEXT;
            break;
          }
        } catch (StopIteratingException stop) {
          break;
        }
        if (inputIt.hasNext()) {
          try {
            Iterable<V> transSeq = translator.invoke(inputIt.next());
            if (Sequence.USE_NULL_SEQUENCE) {
              if (transSeq == null) {
                transSeq = NullSequence.instance();
              }
            }
            transIt = transSeq.iterator();
          } catch (StopIteratingException illegal) {
            throw new IllegalStateException(illegal);
          }
        } else {
          break;
        }
      } while (true);
    }
    private V clearNext() {
      V tmp = next;
      next = null;
      hasNext = HasNextState.UNKNOWN;
      return tmp;
    }
  }
}