content: /*****************************************************************
   *   Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
   *  with the License.  You may obtain a copy of the License at
   *
   *    https://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License.
   ****************************************************************/
  /* ====================================================================
   *
   * Copyright(c) 2003, Andriy Shapochka
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above
   *    copyright notice, this list of conditions and the following
   *    disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above
   *    copyright notice, this list of conditions and the following
   *    disclaimer in the documentation and/or other materials
   *    provided with the distribution.
   *
   * 3. Neither the name of the ASHWOOD nor the
   *    names of its contributors may be used to endorse or
   *    promote products derived from this software without
   *    specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ====================================================================
   *
   * This software consists of voluntary contributions made by
   * individuals on behalf of the ASHWOOD Project and was originally
   * created by Andriy Shapochka.
   *
   */
  package org.apache.cayenne.ashwood.graph;
  
  import java.util.NoSuchElementException;
  import java.util.function.Predicate;
  
  
  /**
   * @since 3.1
   */
  public class FilterArcIterator<E, V> implements ArcIterator<E, V> {
  
      private ArcIterator<E, V> iterator;
      private Predicate<E> acceptOrigin, acceptDestination;
      private Predicate<V> acceptArc;
  
      private E nextOrigin, nextDst;
      private V nextArc;
      private boolean nextObjectSet = false;
  
      public FilterArcIterator(ArcIterator<E, V> iterator, Predicate<E> acceptOrigin,
              Predicate<E> acceptDestination, Predicate<V> acceptArc) {
  
          this.iterator = iterator;
          this.acceptOrigin = acceptOrigin;
          this.acceptDestination = acceptDestination;
          this.acceptArc = acceptArc;
          nextOrigin = iterator.getOrigin();
          if (!acceptOrigin.test(nextOrigin)) {
              nextOrigin = null;
          }
          nextDst = iterator.getDestination();
          if (!acceptDestination.test(nextDst)) {
              nextDst = null;
          }
      }
  
      public E getOrigin() {
          return nextOrigin;
      }
  
      public E getDestination() {
          return nextDst;
      }
  
      public boolean hasNext() {
          if (nextObjectSet) {
              return true;
          }
          else {
              return setNextObject();
          }
      }
  
      public V next() {
          if (!nextObjectSet) {
              if (!setNextObject()) {
                  throw new NoSuchElementException();
              }
          }
          nextObjectSet = false;
          return nextArc;
      }
  
      public void remove() {
          throw new UnsupportedOperationException();
      }
  
      private boolean setNextObject() {
  
          while (iterator.hasNext()) {
              V arc = iterator.next();
              E origin = iterator.getOrigin();
              E dst = iterator.getDestination();
              if (acceptOrigin.test(origin)
                      && acceptArc.test(arc)
                      && acceptDestination.test(dst)) {
                  nextArc = arc;
                  nextOrigin = origin;
                  nextDst = dst;
                  nextObjectSet = true;
                  return true;
              }
          }
          return false;
      }
  }
  