package edu.washington.escience.myria.operator;

import java.util.Objects;

import com.google.common.base.Preconditions;

import edu.washington.escience.myria.Schema;

public abstract class NAryOperator extends Operator {

  /**
   * The children of the n-ary operator.
   * */
  protected Operator[] children;

  public NAryOperator() {
    super();
  }

  @Override
  public Operator[] getChildren() {
    return children;
  }

  @Override
  public void setChildren(final Operator[] children) {
    Objects.requireNonNull(children);
    Preconditions.checkArgument(children.length > 0);
    this.children = children;
  }

  @Override
  public Schema getSchema() {
    return children[0].getSchema();
  }

  /**
   * @return number of children
   */
  protected int numChildren() {
    return children.length;
  }

}
@@ -161,16 +161,51 @@
 chema;%0A%0A
+/**%0A * %0A * @author dominik%0A * %0A */%0A
 public a
@@ -251,16 +251,110 @@
 ator %7B%0A%0A
+  /** Required for Java serialization. */%0A  private static final long serialVersionUID = 1L;%0A%0A
   /**%0A  
@@ -434,16 +434,61 @@
 ldren;%0A%0A
+  /**%0A   * Default, empty constructor.%0A   */%0A
   public

Write comments in n-ary operator