com.orientechnologies.common.util.OCollections Maven / Gradle / Ivy

/*
  *
  *  *  Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
  *  *
  *  *  Licensed 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.
  *  *
  *  * For more information: http://www.orientechnologies.com
  *
  */

package com.orientechnologies.common.util;

import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

/**
 * Set of utility methods to work with collections.
 */
public class OCollections {
  /**
   * This method is used to find item in collection using passed in comparator. Only 0 value (requested object is found) returned by
   * comparator is taken into account the rest is ignored.
   * 
   * 
   * @param list
   *          List in which value should be found.
   * @param object
   *          Object to find.
   * @param comparator
   *          Comparator is sued for search.
   * @param 
   *          Type of collection elements.
   * @return Index of found item or -1 otherwise.
   */
  public static  int indexOf(final List list, final T object, final Comparator comparator) {
    int i = 0;
    for (final T item : list) {
      if (comparator.compare(item, object) == 0)
        return i;
      i++;
    }
    return -1;
  }

  /**
   * Create a string representation of all objects in the given Iterable. example : [value1,value2,value3]
   * 
   * @param iterable
   * @return String
   */
  public static String toString(Iterable iterable) {
    final StringBuilder builder = new StringBuilder(512);
    builder.append('[');
    int cnt = 0;
    final Iterator ite = iterable.iterator();
    while (ite.hasNext()) {
      if (cnt != 0) {
        builder.append(',');
      }
      cnt++;
      final Object obj = ite.next();
      builder.append(obj);
    }
    builder.append(']');
    return builder.toString();
  }
}