LimitedCardinalitySequence.java

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

/*Generated by MPS */

import jetbrains.mps.internal.collections.runtime.Sequence;
import jetbrains.mps.internal.collections.runtime.AbstractSequence;
import java.util.Iterator;
import java.util.NoSuchElementException;

public class LimitedCardinalitySequence<U> extends Sequence<U> {
  private final AbstractSequence<U> input;
  private final int maxCardinality;
  public LimitedCardinalitySequence(AbstractSequence<U> input, int maxCardinality) {
    if (input == null) {
      throw new NullPointerException();
    }
    this.input = input;
    this.maxCardinality = maxCardinality;
  }
  @Override
  public Iterator<U> iterator() {
    return new LimitedCardinalitySequence.LimitedCardinalityIterator();
  }
  private class LimitedCardinalityIterator implements Iterator<U> {
    private Iterator<U> inputIt;
    private CardinalityMap<U> cardMap;
    private U next;
    private HasNextState hasNext = HasNextState.UNKNOWN;
    public LimitedCardinalityIterator() {
    }
    @Override
    public boolean hasNext() {
      if (inputIt == null) {
        init();
      }
      if (hasNext.unknown()) {
        moveToNext();
      }
      return hasNext.hasNext();
    }
    @Override
    public U 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 moveToNext() {
      next = null;
      hasNext = HasNextState.AT_END;
      while (inputIt.hasNext()) {
        U tmp = inputIt.next();
        if (cardMap.postInc(tmp) < maxCardinality) {
          next = tmp;
          hasNext = HasNextState.HAS_NEXT;
          return;
        }
      }
      cardMap.clear();
    }
    private U clearNext() {
      U tmp = next;
      next = null;
      hasNext = HasNextState.UNKNOWN;
      return tmp;
    }
    private void init() {
      inputIt = input.iterator();
      cardMap = new CardinalityMap<U>();
    }
  }
}