ObjectCombinationGenericOrdering.java

/*
 * 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
 *
 *   http://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.
 */

package org.apache.streams.verbs;

import com.google.common.collect.Ordering;

/**
 * Orders ObjectCombinations from most specific to most general, without regard
 * for degree of match to any specific Activity.
 */
public class ObjectCombinationGenericOrdering extends Ordering<ObjectCombination> {

  public ObjectCombinationGenericOrdering() {}

  @Override
  public int compare(ObjectCombination left, ObjectCombination right) {
    if ( wildcardCount(left) < wildcardCount(right)) {
      return -1;
    } else if ( wildcardCount(left) > wildcardCount(right)) {
      return 1;
    } else if ( !wildcard(left.getActor()) && wildcard(right.getActor())) {
      return -1;
    } else if ( wildcard(left.getActor()) && !wildcard(right.getActor())) {
      return 1;
    } else if ( !wildcard(left.getObject()) && wildcard(right.getObject())) {
      return -1;
    } else if ( wildcard(left.getObject()) && !wildcard(right.getObject())) {
      return 1;
    } else if ( !wildcard(left.getTarget()) && wildcard(right.getTarget())) {
      return -1;
    } else if ( wildcard(left.getTarget()) && !wildcard(right.getTarget())) {
      return 1;
    } else if ( !wildcard(left.getProvider()) && wildcard(right.getProvider())) {
      return -1;
    } else if ( wildcard(left.getProvider()) && !wildcard(right.getProvider())) {
      return 1;
    } else {
      return 0;
    }
  }

  /**
   * count wildcards in this ObjectCombination.
   * @param objectCombination ObjectCombination
   * @return count
   */
  private int wildcardCount(ObjectCombination objectCombination) {
    int wildcardCount = 0;
    if ( wildcard(objectCombination.getActor())) {
      wildcardCount++;
    }
    if ( wildcard(objectCombination.getObject())) {
      wildcardCount++;
    }
    if ( wildcard(objectCombination.getTarget())) {
      wildcardCount++;
    }
    if ( wildcard(objectCombination.getProvider())) {
      wildcardCount++;
    }
    return wildcardCount;
  }

  /**
   * is pattern a wildcard.
   * @param pattern String
   * @return true or false
   */
  private boolean wildcard(String pattern) {
    return pattern.equals("*");
  }
}