/*
 * $Id: CollectionUtil.java,v 1.3 2002-10-06 21:22:04 tal Exp $
 */

/*

Copyright (c) 2002 Board of Trustees of Leland Stanford Jr. University,
all rights reserved.

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
STANFORD UNIVERSITY 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.

Except as contained in this notice, the name of Stanford University shall not
be used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from Stanford University.

*/

package org.lockss.util;
import java.util.*;

/** Utilities for Collections.
 */
public class CollectionUtil {
  /** Return true iff the two iterators enumerate collections of the same
   * size, whose elements are pairwise equal.  The collections need not be of
   * the same type.
   */
  public static boolean isIsomorphic(Iterator a, Iterator b) {
    while (a.hasNext()) {
      if (!b.hasNext()) {
	return false;
      }
      Object ao = a.next();
      Object bo = b.next();
      if (ao == null) {
	if (bo != null) {
	  return false;
	}
      } else if (!ao.equals(bo)) {
	return false;
      }
    }
    return !b.hasNext();
  }

  /** Return true iff the two collections are the same size and have
   * elements that are pairwise equal.  The collections need not be of the
   * same type.
   */
  public static boolean isIsomorphic(Collection a, Collection b) {
    return isIsomorphic(a.iterator(), b.iterator());
  }

  /** Return true iff the collection and array are isomorphic */
  public static boolean isIsomorphic(Collection a, Object b[]) {
    return isIsomorphic(a.iterator(), new ArrayIterator(b));
  }

  /** Return true iff the array and collection are isomorphic */
  public static boolean isIsomorphic(Object a[], Collection b) {
    return isIsomorphic(new ArrayIterator(a), b.iterator());
  }

  /** Return true iff the two arrays are isomorphic */
  public static boolean isIsomorphic(Object a[], Object b[]) {
    return isIsomorphic(new ArrayIterator(a), new ArrayIterator(b));
  }
}

/*
 * $Id: CollectionUtil.java,v 1.4 2002-10-16 03:42:07 tal Exp $
 */

/*

Copyright (c) 2002 Board of Trustees of Leland Stanford Jr. University,
all rights reserved.

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
STANFORD UNIVERSITY 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.

Except as contained in this notice, the name of Stanford University shall not
be used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from Stanford University.

*/

package org.lockss.util;
import java.util.*;

/** Utilities for Collections.
 */
public class CollectionUtil {
  /** Return true iff the two iterators enumerate collections of the same
   * size, whose elements are pairwise equal.  The collections need not be of
   * the same type.
   */
  public static boolean isIsomorphic(Iterator a, Iterator b) {
    while (a.hasNext()) {
      if (!b.hasNext()) {
	return false;
      }
      Object ao = a.next();
      Object bo = b.next();
      if (ao == null) {
	if (bo != null) {
	  return false;
	}
      } else if (!ao.equals(bo)) {
	return false;
      }
    }
    return !b.hasNext();
  }

  /** Return true iff the two collections are the same size and have
   * elements that are pairwise equal.  The collections need not be of the
   * same type.
   */
  public static boolean isIsomorphic(Collection a, Collection b) {
    if (a == null) {
      return b == null;
    }
    // Sigh, can't rely on overloading to catch Sets due to static typing.
    // (E.g., we're likely to be called from assertIsomorphic())
    if (a instanceof Set) {
      return ((Set)a).equals(b);
    }
    // Similarly.
    if (!isCompatibleTypes(a, b)) {
      return false;
    }
    return isIsomorphic(a.iterator(), b.iterator());
  }

  /** Return true iff the collection and array are isomorphic */
  public static boolean isIsomorphic(Collection a, Object b[]) {
    return isIsomorphic(a.iterator(), new ArrayIterator(b));
  }

  /** Return true iff the array and collection are isomorphic */
  public static boolean isIsomorphic(Object a[], Collection b) {
    return isIsomorphic(new ArrayIterator(a), b.iterator());
  }

  /** Return true iff the two arrays are isomorphic */
  public static boolean isIsomorphic(Object a[], Object b[]) {
    return isIsomorphic(new ArrayIterator(a), new ArrayIterator(b));
  }

  // Check that the two collection types can possibly be equal.
  // Ordered vs. unordered (e.g., Set) can't be.
  private static boolean isCompatibleTypes(Collection a, Collection b) {
    return (a instanceof Set) == (b instanceof Set);
  }
}

Fix comparison of unordered collections (Sets)