001/*
002 * Copyright (c) 2010-2021 Mark Allen, Norbert Bartels.
003 *
004 * Permission is hereby granted, free of charge, to any person obtaining a copy
005 * of this software and associated documentation files (the "Software"), to deal
006 * in the Software without restriction, including without limitation the rights
007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
008 * copies of the Software, and to permit persons to whom the Software is
009 * furnished to do so, subject to the following conditions:
010 *
011 * The above copyright notice and this permission notice shall be included in
012 * all copies or substantial portions of the Software.
013 *
014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
020 * THE SOFTWARE.
021 */
022package com.restfb.util;
023
024import static com.restfb.util.StringUtils.isBlank;
025
026import java.util.Collection;
027import java.util.Map;
028import java.util.Objects;
029import java.util.function.Supplier;
030
031public class ObjectUtil {
032
033  private ObjectUtil() {
034    // prevent instantiation
035  }
036
037  /**
038   * Ensures that {@code obj} isn't {@code null} or an empty string.
039   *
040   * @param obj
041   *          The parameter to check.
042   * @param errorText
043   *          The exception message.
044   * @throws IllegalArgumentException
045   *           If {@code obj} is {@code null} or an empty string.
046   */
047  public static String requireNotEmpty(String obj, String errorText) {
048    if (isBlank(obj)) {
049      throw new IllegalArgumentException(errorText);
050    }
051    return obj;
052  }
053
054  /**
055   * Ensures that {@code obj} isn't {@code null}.
056   *
057   * @param obj
058   *          The parameter to check.
059   * @param exceptionSupplier
060   *          The supplier for the exception that is thrown if obj is null.
061   * @throws T
062   *           If {@code obj} is {@code null}.
063   */
064  public static <T extends Exception> void requireNotNull(Object obj, Supplier<T> exceptionSupplier) throws T {
065    if (obj == null) {
066      throw exceptionSupplier.get();
067    }
068  }
069
070  /**
071   * Checks is the object is a empty 'collection' or 'map'.
072   * 
073   * @param obj
074   *          the object that is checked
075   * @return {@code true} if the given object is a empty collection or an empty map, {@code false} otherwise
076   */
077  public static boolean isEmptyCollectionOrMap(Object obj) {
078    if (obj instanceof Collection) {
079      return ((Collection) obj).isEmpty();
080    }
081
082    return (obj instanceof Map && ((Map) obj).isEmpty());
083  }
084
085  /**
086   * Ensures that {@code parameter} isn't {@code null} or an empty string.
087   *
088   * @param parameterName
089   *          The name of the parameter (to be used in exception message).
090   * @param parameter
091   *          The parameter to check.
092   * @throws IllegalArgumentException
093   *           If {@code parameter} is {@code null} or an empty string.
094   */
095  public static void verifyParameterPresence(String parameterName, String parameter) {
096    verifyParameterPresence(parameterName, (Object) parameter);
097    requireNotEmpty(parameter, "The '" + parameterName + "' parameter cannot be an empty string.");
098  }
099
100  /**
101   * Ensures that {@code parameter} isn't {@code null}.
102   *
103   * @param parameterName
104   *          The name of the parameter (to be used in exception message).
105   * @param parameter
106   *          The parameter to check.
107   * @throws NullPointerException
108   *           If {@code parameter} is {@code null}.
109   */
110  public static void verifyParameterPresence(String parameterName, Object parameter) {
111    Objects.requireNonNull(parameter, "The '" + parameterName + "' parameter cannot be null.");
112  }
113}