code: /*
   * 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.commons.lang;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Map;
  
  /**
   * <p>Assists in validating arguments.</p>
   * 
   * <p>The class is based along the lines of JUnit. If an argument value is 
   * deemed invalid, an IllegalArgumentException is thrown. For example:</p>
   * 
   * <pre>
   * Validate.isTrue( i > 0, "The value must be greater than zero: ", i);
   * Validate.notNull( surname, "The surname must not be null");
   * </pre>
   *
   * @author <a href="mailto:ola.berg@arkitema.se">Ola Berg</a>
   * @author Stephen Colebourne
   * @author Gary Gregory
   * @author Norm Deane
   * @since 2.0
   * @version $Id: Validate.java 437554 2006-08-28 06:21:41Z bayard $
   */
  public class Validate {
      // Validate has no dependencies on other classes in Commons Lang at present
      
      /**
       * Constructor. This class should not normally be instantiated.
       */
      public Validate() {
        super();
      }
      
      // isTrue
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the test result is <code>false</code>.</p>
       * 
       * <p>This is used when validating according to an arbitrary boolean expression,
       * such as validating a primitive number or using your own custom validation 
       * expression.</p>
       *
       * <pre>
       * Validate.isTrue( myObject.isOk(), "The object is not OK: ", myObject);
       * </pre>
       *
       * <p>For performance reasons, the object is passed as a separate parameter and
       * appended to the message string only in the case of an error.</p>
       * 
       * @param expression  a boolean expression
       * @param message  the exception message you would like to see if the
       *  expression is <code>false</code>
       * @param value  the value to append to the message in case of error
       * @throws IllegalArgumentException if expression is <code>false</code>
       */
      public static void isTrue(boolean expression, String message, Object value) {
          if (expression == false) {
              throw new IllegalArgumentException(message + value);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the test result is <code>false</code>.</p>
       * 
       * <p>This is used when validating according to an arbitrary boolean expression,
       * such as validating a primitive number or using your own custom validation 
       * expression.</p>
       *
       * <pre>
       * Validate.isTrue( i > 0, "The value must be greater than zero: ", i);
       * </pre>
       *
       * <p>For performance reasons, the long value is passed as a separate parameter and
       * appended to the message string only in the case of an error.</p>
       * 
       * @param expression  a boolean expression
       * @param message  the exception message you would like to see if the expression is <code>false</code>
       * @param value  the value to append to the message in case of error
       * @throws IllegalArgumentException if expression is <code>false</code>
       */
      public static void isTrue(boolean expression, String message, long value) {
          if (expression == false) {
              throw new IllegalArgumentException(message + value);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the test result is <code>false</code>.</p>
       * 
       * <p>This is used when validating according to an arbitrary boolean expression,
       * such as validating a primitive number or using your own custom validation 
       * expression.</p>
       *
       * <pre>
       * Validate.isTrue( d > 0.0, "The value must be greater than zero: ", d);
       * </pre>
       *
       * <p>For performance reasons, the double value is passed as a separate parameter and
       * appended to the message string only in the case of an error.</p>
       * 
       * @param expression  a boolean expression
       * @param message  the exception message you would like to see if the expression
       *  is <code>false</code>
       * @param value  the value to append to the message in case of error
       * @throws IllegalArgumentException if expression is <code>false</code>
       */
      public static void isTrue(boolean expression, String message, double value) {
          if (expression == false) {
              throw new IllegalArgumentException(message + value);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the test result is <code>false</code>.</p>
       * 
       * <p>This is used when validating according to an arbitrary boolean expression,
       * such as validating a primitive number or using your own custom validation 
       * expression.</p>
       *
       * <pre>
       * Validate.isTrue( (i > 0), "The value must be greater than zero");
       * Validate.isTrue( myObject.isOk(), "The object is not OK");
       * </pre>
       *
       * <p>For performance reasons, the message string should not involve a string append,
       * instead use the {@link #isTrue(boolean, String, Object)} method.</p>
       * 
       * @param expression  a boolean expression
       * @param message  the exception message you would like to see if the expression
       *  is <code>false</code>
       * @throws IllegalArgumentException if expression is <code>false</code>
       */
      public static void isTrue(boolean expression, String message) {
          if (expression == false) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the test result is <code>false</code>.</p>
       * 
       * <p>This is used when validating according to an arbitrary boolean expression,
       * such as validating a primitive number or using your own custom validation 
       * expression.</p>
       *
       * <pre>
       * Validate.isTrue( i > 0 );
       * Validate.isTrue( myObject.isOk() );
       * </pre>
       *
       * <p>The message in the exception is 'The validated expression is false'.</p>
       * 
       * @param expression  a boolean expression
       * @throws IllegalArgumentException if expression is <code>false</code>
       */
      public static void isTrue(boolean expression) {
          if (expression == false) {
              throw new IllegalArgumentException("The validated expression is false");
          }
      }
  
      // notNull
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument is <code>null</code>.</p>
       *
       * <pre>
       * Validate.notNull(myObject, "The object must not be null");
       * </pre>
       * 
       * @param object  the object to check is not <code>null</code>
       * @param message  the exception message you would like to see
       *  if the object is <code>null</code>
       * @throws IllegalArgumentException if the object is <code>null</code>
       */
      public static void notNull(Object object, String message) {
          if (object == null) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument is <code>null</code>.</p>
       *
       * <pre>
       * Validate.notNull(myObject);
       * </pre>
       *
       * <p>The message in the exception is 'The validated object is null'.</p>
       * 
       * @param object  the object to check is not <code>null</code>
       * @throws IllegalArgumentException if the object is <code>null</code>
       */
      public static void notNull(Object object) {
          if (object == null) {
              throw new IllegalArgumentException("The validated object is null");
          }
      }
  
      // notEmpty array
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument array is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myArray, "The array must not be empty");
       * </pre>
       * 
       * @param array  the array to check is not empty
       * @param message  the exception message you would like to see if the array is empty
       * @throws IllegalArgumentException if the array is empty
       */
      public static void notEmpty(Object[] array, String message) {
          if (array == null || array.length == 0) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument array is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myArray);
       * </pre>
       *
       * <p>The message in the exception is 'The validated array is empty'.
       * 
       * @param array  the array to check is not empty
       * @throws IllegalArgumentException if the array is empty
       */
      public static void notEmpty(Object[] array) {
          if (array == null || array.length == 0) {
              throw new IllegalArgumentException("The validated array is empty");
          }
      }
  
      // notEmpty collection
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Collection is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myCollection, "The collection must not be empty");
       * </pre>
       * 
       * @param collection  the collection to check is not empty
       * @param message  the exception message you would like to see if the collection is empty
       * @throws IllegalArgumentException if the collection is empty
       */
      public static void notEmpty(Collection collection, String message) {
          if (collection == null || collection.size() == 0) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Collection is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myCollection);
       * </pre>
       *
       * <p>The message in the exception is 'The validated collection is empty'.</p>
       * 
       * @param collection  the collection to check is not empty
       * @throws IllegalArgumentException if the collection is empty
       */
      public static void notEmpty(Collection collection) {
          if (collection == null || collection.size() == 0) {
              throw new IllegalArgumentException("The validated collection is empty");
          }
      }
  
      // notEmpty map
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Map is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myMap, "The map must not be empty");
       * </pre>
       * 
       * @param map  the map to check is not empty
       * @param message  the exception message you would like to see if the map is empty
       * @throws IllegalArgumentException if the map is empty
       */
      public static void notEmpty(Map map, String message) {
          if (map == null || map.size() == 0) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Map is empty (<code>null</code> or no elements).</p>
       *
       * <pre>
       * Validate.notEmpty(myMap);
       * </pre>
       *
       * <p>The message in the exception is 'The validated map is empty'.</p>
       * 
       * @param map  the map to check is not empty
       * @throws IllegalArgumentException if the map is empty
       */
      public static void notEmpty(Map map) {
          if (map == null || map.size() == 0) {
              throw new IllegalArgumentException("The validated map is empty");
          }
      }
  
      // notEmpty string
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument String is empty (<code>null</code> or zero length).</p>
       *
       * <pre>
       * Validate.notEmpty(myString, "The string must not be empty");
       * </pre>
       * 
       * @param string  the string to check is not empty
       * @param message  the exception message you would like to see if the string is empty
       * @throws IllegalArgumentException if the string is empty
       */
      public static void notEmpty(String string, String message) {
          if (string == null || string.length() == 0) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument String is empty (<code>null</code> or zero length).</p>
       *
       * <pre>
       * Validate.notEmpty(myString);
       * </pre>
       *
       * <p>The message in the exception is 'The validated string is empty'.</p>
       * 
       * @param string  the string to check is not empty
       * @throws IllegalArgumentException if the string is empty
       */
      public static void notEmpty(String string) {
          if (string == null || string.length() == 0) {
              throw new IllegalArgumentException("The validated string is empty");
          }
      }
  
      // notNullElements array
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument array has <code>null</code> elements or is
       * <code>null</code>.</p>
       *
       * <pre>
       * Validate.noNullElements(myArray, "The array must not contain null elements");
       * </pre>
       * 
       * <p>If the array is null then the message in the exception is 'The validated object is null'.</p>
       *
       * @param array  the array to check
       * @param message  the exception message if the array has
       *  <code>null</code> elements
       * @throws IllegalArgumentException if the array has <code>null</code>
       *  elements or is <code>null</code>
       */
      public static void noNullElements(Object[] array, String message) {
          Validate.notNull(array);
          for (int i = 0; i < array.length; i++) {
              if (array[i] == null) {
                  throw new IllegalArgumentException(message);
              }
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument array has <code>null</code> elements or is
       * <code>null</code>.</p>
       *
       * <pre>
       * Validate.noNullElements(myArray);
       * </pre>
       *
       * <p>If the array has a null element the message in the exception is
       * 'The validated array contains null element at index: '.</p>
       *
       * <p>If the array is null then the message in the exception is 'The validated object is null'.</p>
       * 
       * @param array  the array to check
       * @throws IllegalArgumentException if the array has <code>null</code>
       *  elements or is <code>null</code>
       */
      public static void noNullElements(Object[] array) {
          Validate.notNull(array);
          for (int i = 0; i < array.length; i++) {
              if (array[i] == null) {
                  throw new IllegalArgumentException("The validated array contains null element at index: " + i);
              }
          }
      }
  
      // notNullElements collection
      //---------------------------------------------------------------------------------
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Collection has <code>null</code> elements or is
       * <code>null</code>.</p>
       *
       * <pre>
       * Validate.noNullElements(myCollection, "The collection must not contain null elements");
       * </pre>
       *
       * <p>If the collection is null then the message in the exception is 'The validated object is null'.</p>
       * 
       * @param collection  the collection to check
       * @param message  the exception message if the collection has
       *  <code>null</code> elements
       * @throws IllegalArgumentException if the collection has
       *  <code>null</code> elements or is <code>null</code>
       */
      public static void noNullElements(Collection collection, String message) {
          Validate.notNull(collection);
          for (Iterator it = collection.iterator(); it.hasNext();) {
              if (it.next() == null) {
                  throw new IllegalArgumentException(message);
              }
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument Collection has <code>null</code> elements or is
       * <code>null</code>.</p>
       *
       * <pre>
       * Validate.noNullElements(myCollection);
       * </pre>
       *
       * <p>The message in the exception is 'The validated collection contains null element at index: '.</p>
       *
       * <p>If the collection is null then the message in the exception is 'The validated object is null'.</p>
       * 
       * @param collection  the collection to check
       * @throws IllegalArgumentException if the collection has
       *  <code>null</code> elements or is <code>null</code>
       */
      public static void noNullElements(Collection collection) {
          Validate.notNull(collection);
          int i = 0;
          for (Iterator it = collection.iterator(); it.hasNext(); i++) {
              if (it.next() == null) {
                  throw new IllegalArgumentException("The validated collection contains null element at index: " + i);
              }
          }
      }
  
      /**
       * <p>Validate an argument, throwing <code>IllegalArgumentException</code>
       * if the argument collection  is <code>null</code> or has elements that
       * are not of type <code>clazz</code> or a subclass.</p>
       *
       * <pre>
       * Validate.allElementsOfType(collection, String.class, "Collection has invalid elements");
       * </pre>
       *
       * @param collection  the collection to check, not null
       * @param clazz  the <code>Class</code> which the collection's elements are expected to be, not null
       * @param message  the exception message if the <code>Collection</code> has elements not of type <code>clazz</code>
       * @since 2.1
       */
      public static void allElementsOfType(Collection collection, Class clazz, String message) {
          Validate.notNull(collection);
          Validate.notNull(clazz);
          for (Iterator it = collection.iterator(); it.hasNext(); ) {
              if (clazz.isInstance(it.next()) == false) {
                  throw new IllegalArgumentException(message);
              }
          }
      }
  
      /**
       * <p>
       * Validate an argument, throwing <code>IllegalArgumentException</code> if the argument collection is
       * <code>null</code> or has elements that are not of type <code>clazz</code> or a subclass.
       * </p>
       * 
       * <pre>
       * Validate.allElementsOfType(collection, String.class);
       * </pre>
       * 
       * <p>
       * The message in the exception is 'The validated collection contains an element not of type clazz at index: '.
       * </p>
       * 
       * @param collection
       *            the collection to check, not null
       * @param clazz
       *            the <code>Class</code> which the collection's elements are expected to be, not null
       * @since 2.1
       */
      public static void allElementsOfType(Collection collection, Class clazz) {
          Validate.notNull(collection);
          Validate.notNull(clazz);
          int i = 0;
          for (Iterator it = collection.iterator(); it.hasNext(); i++) {
              if (clazz.isInstance(it.next()) == false) {
                  throw new IllegalArgumentException("The validated collection contains an element not of type "
                      + clazz.getName() + " at index: " + i);
              }
          }
      }
  
  }
  