gateway-util-common/src/main/java/org/apache/knox/gateway/util/CollectionUtils.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.knox.gateway.util;

import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;

public class CollectionUtils {

  public static <T> boolean isSorted(Collection<T> collection, Comparator<T> comparator) {
    if (collection != null) {
      if (collection.isEmpty() || collection.size() == 1) {
        return true;
      }

      final Iterator<T> iterator = collection.iterator();
      T current, previous = iterator.next();
      while (iterator.hasNext()) {
        current = iterator.next();
        if (comparator.compare(previous, current) > 0) {
          return false;
        }
        previous = current;
      }
      return true;
    } else {
      return false;
    }
  }

}