content: /* Alloy Analyzer 4 -- Copyright (c) 2006-2009, Felix Chang
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
   * (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
   * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
   * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  package edu.mit.csail.sdg.translator;
  
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  import edu.mit.csail.sdg.alloy4.ErrorAPI;
  import kodkod.instance.Tuple;
  import kodkod.instance.TupleSet;
  
  /**
   * Immutable; represents a collection of Alloy tuples; comparison is by identity
   * rather than by value.
   */
  
  public final class A4TupleSet implements Iterable<A4Tuple> {
  
      /** The Kodkod tupleset. */
      private final TupleSet   tuples;
  
      /** The A4Solution that this came from. */
      private final A4Solution sol;
  
      /**
       * Construct a TupleSet from the kodkod TupleSet, while renaming each atom using
       * the atom2name map in sol. <br>
       * NOTE: caller must ensure the Kodkod tupleset is not modified, since we expect
       * the resulting A4Tupleset to be constant.
       */
      A4TupleSet(TupleSet tuples, A4Solution sol) {
          this.tuples = tuples;
          this.sol = sol;
      }
  
      /** Return the underlying Kodkod tupleset. */
      public TupleSet debugGetKodkodTupleset() {
          return tuples.clone();
      }
  
      /**
       * Returns a read-only iterator that iterates over each tuple in this TupleSet.
       */
      @Override
      public Iterator<A4Tuple> iterator() {
          return new Iterator<A4Tuple>() {
  
              private final Iterator<Tuple> it = tuples.iterator();
  
              @Override
              public final boolean hasNext() {
                  return it.hasNext();
              }
  
              @Override
              public final A4Tuple next() {
                  if (!it.hasNext())
                      throw new NoSuchElementException();
                  return new A4Tuple(it.next(), sol);
              }
  
              @Override
              public final void remove() {
                  throw new UnsupportedOperationException();
              }
          };
      }
  
      /** Returns the arity. */
      public int arity() {
          return tuples.arity();
      }
  
      /** Returns the number of tuples in this tuple set. */
      public int size() {
          return tuples.size();
      }
  
      /**
       * Construct a new tupleset as the product of this and that; this and that must
       * be come from the same solution.
       */
      public A4TupleSet product(A4TupleSet that) throws ErrorAPI {
          if (sol != that.sol)
              throw new ErrorAPI("A4TupleSet.product() requires 2 tuplesets from the same A4Solution.");
          return new A4TupleSet(tuples.product(that.tuples), sol);
      }
  
      /**
       * Construct a new tupleset as the union of this and that; this and that must be
       * come from the same solution. Note: if that==null, then the method returns
       * this A4TupleSet as-is.
       */
      public A4TupleSet plus(A4TupleSet that) throws ErrorAPI {
          if (that == null)
              return this;
          if (sol != that.sol)
              throw new ErrorAPI("A4TupleSet.plus() requires 2 tuplesets from the same A4Solution.");
          if (arity() != that.arity())
              throw new ErrorAPI("A4TupleSet.plus() requires 2 tuplesets with the same arity.");
          if (this == that || tuples.size() == 0)
              return that;
          else if (that.tuples.size() == 0)
              return this; // special short cut
          TupleSet ts = tuples.clone();
          ts.addAll(that.tuples);
          if (tuples.size() == ts.size())
              return this;
          if (that.tuples.size() == ts.size())
              return that;
          return new A4TupleSet(ts, sol);
      }
  
      /**
       * Construct a new tupleset as the subtraction of this and that; this and that
       * must be come from the same solution. Note: if that==null, then the method
       * returns this A4TupleSet as-is.
       */
      public A4TupleSet minus(A4TupleSet that) throws ErrorAPI {
          if (that == null)
              return this;
          if (sol != that.sol)
              throw new ErrorAPI("A4TupleSet.minus() requires 2 tuplesets from the same A4Solution.");
          if (arity() != that.arity())
              throw new ErrorAPI("A4TupleSet.minus() requires 2 tuplesets with the same arity.");
          if (tuples.size() == 0 || that.tuples.size() == 0)
              return this; // special short cut
          TupleSet ts = tuples.clone();
          ts.removeAll(that.tuples);
          if (tuples.size() != ts.size())
              return new A4TupleSet(ts, sol);
          else
              return this;
      }
  
      /**
       * Construct a new tupleset as the intersection of this and that; this and that
       * must be come from the same solution.
       */
      public A4TupleSet intersect(A4TupleSet that) throws ErrorAPI {
          if (sol != that.sol)
              throw new ErrorAPI("A4TupleSet.intersect() requires 2 tuplesets from the same A4Solution.");
          if (arity() != that.arity())
              throw new ErrorAPI("A4TupleSet.intersect() requires 2 tuplesets with the same arity.");
          if (this.tuples.size() == 0)
              return this; // special short cut
          if (that.tuples.size() == 0)
              return that; // special short cut
          TupleSet ts = tuples.clone();
          ts.retainAll(that.tuples);
          if (tuples.size() != ts.size())
              return new A4TupleSet(ts, sol);
          else
              return this;
      }
  
      /** Prints a human-readable description of this TupleSet. */
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder("{");
          for (A4Tuple t : this) {
              if (sb.length() > 1)
                  sb.append(", ");
              sb.append(t);
          }
          return sb.append('}').toString();
      }
  }
  