/*
 * Copyright 1998-2015 University Corporation for Atmospheric Research/Unidata
 *
 *   Portions of this software were developed by the Unidata Program at the
 *   University Corporation for Atmospheric Research.
 *
 *   Access and use of this software shall impose the following obligations
 *   and understandings on the user. The user is granted the right, without
 *   any fee or cost, to use, copy, modify, alter, enhance and distribute
 *   this software, and any derivative works thereof, and its supporting
 *   documentation for any purpose whatsoever, provided that this entire
 *   notice appears in all copies of the software, derivative works and
 *   supporting documentation.  Further, UCAR requests that the user credit
 *   UCAR/Unidata in any publications that result from the use of this
 *   software or in any product that includes this software. The names UCAR
 *   and/or Unidata, however, may not be used in any advertising or publicity
 *   to endorse or promote any products or commercial entity unless specific
 *   written permission is obtained from UCAR/Unidata. The user also
 *   understands that UCAR/Unidata is not obligated to provide the user with
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 *   to the use, operation and performance of this software nor to provide
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 *
 *   THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
 *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *   DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
 *   INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 *   FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 *   WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
 */
package thredds.inventory;

import ucar.nc2.util.CloseableIterator;

import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * An iterator over MFiles, closeable so its a target for try-with-resource
 *
 * @author caron
 * @since 11/20/13
 */
public class MFileIterator implements CloseableIterator<MFile> {
  private Iterator<MFile> iter;
  private MFileFilter filter;
  private MFile nextMfile;

  /**
   * Constructor
   * @param iter   iterator over MFiles
   * @param filter optional filter, may be null
   */
  public MFileIterator(Iterator<MFile> iter, MFileFilter filter) {
    this.iter = iter;
    this.filter = filter;
  }

  public void close() throws IOException {
  }

  public boolean hasNext() {
    while (true) {
      if (!iter.hasNext()) {
        nextMfile = null;
        return false;
      }
      nextMfile = iter.next();
      if (filter == null || filter.accept(nextMfile)) return true;
    }
  }

  public MFile next() {
    if (nextMfile == null) throw new NoSuchElementException();
    return nextMfile;
  }

  public void remove() {
    throw new UnsupportedOperationException();
  }

}