

package org.springframework.util;

import com.google.gwt.core.shared.GwtIncompatible;

import org.springframework.lang.Nullable;

import java.util.Collection;
import java.util.Map;
import java.util.function.Supplier;

/**
 * Assertion utility class that assists in validating arguments.
 *
 * <p>
 * Useful for identifying programmer errors early and clearly at runtime.
 *
 * <p>
 * For example, if the contract of a public method states it does not allow {@code null} arguments,
 * {@code Assert} can be used to validate that contract. Doing this clearly indicates a contract
 * violation when it occurs and protects the class's invariants.
 *
 * <p>
 * Typically used to validate method arguments rather than configuration properties, to check for
 * cases that are usually programmer errors rather than configuration errors. In contrast to
 * configuration initialization code, there is usually no point in falling back to defaults in such
 * methods.
 *
 * <p>
 * This class is similar to JUnit's assertion library. If an argument value is deemed invalid, an
 * {@link IllegalArgumentException} is thrown (typically). For example:
 *
 * <pre class="code">
 * Assert.notNull(clazz, "The class must not be null");
 * Assert.isTrue(i > 0, "The value must be greater than zero");
 * </pre>
 *
 * <p>
 * Mainly for internal use within the framework; consider
 * <a href="http://commons.apache.org/proper/commons-lang/">Apache's Commons Lang</a> for a more
 * comprehensive suite of {@code String} utilities.
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @author Sam Brannen
 * @author Colin Sampaleanu
 * @author Rob Harrop
 * @since 1.1.2
 */
public abstract class Assert {

  /**
   * Assert a boolean expression, throwing an {@code IllegalStateException} if the expression
   * evaluates to {@code false}.
   * <p>
   * Call {@link #isTrue} if you wish to throw an {@code IllegalArgumentException} on an assertion
   * failure.
   *
   * <pre class="code">
   * Assert.state(id == null, "The id property must not already be initialized");
   * </pre>
   *
   * @param expression a boolean expression
   * @param message the exception message to use if the assertion fails
   * @throws IllegalStateException if {@code expression} is {@code false}
   */
  public static void state(final boolean expression, final String message) {
    if (!expression) {
      throw new IllegalStateException(message);
    }
  }

  /**
   * Assert a boolean expression, throwing an {@code IllegalStateException} if the expression
   * evaluates to {@code false}.
   * <p>
   * Call {@link #isTrue} if you wish to throw an {@code IllegalArgumentException} on an assertion
   * failure.
   *
   * <pre class="code">
   * Assert.state(id == null,
   *     () -&gt; "ID for " + entity.getName() + " must not already be initialized");
   * </pre>
   *
   * @param expression a boolean expression
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalStateException if {@code expression} is {@code false}
   * @since 5.0
   */
  public static void state(final boolean expression, final Supplier<String> messageSupplier) {
    if (!expression) {
      throw new IllegalStateException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #state(boolean, String)}
   */
  @Deprecated
  public static void state(final boolean expression) {
    Assert.state(expression, "[Assertion failed] - this state invariant must be true");
  }

  /**
   * Assert a boolean expression, throwing an {@code IllegalArgumentException} if the expression
   * evaluates to {@code false}.
   *
   * <pre class="code">
   * Assert.isTrue(i &gt; 0, "The value must be greater than zero");
   * </pre>
   *
   * @param expression a boolean expression
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if {@code expression} is {@code false}
   */
  public static void isTrue(final boolean expression, final String message) {
    if (!expression) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert a boolean expression, throwing an {@code IllegalArgumentException} if the expression
   * evaluates to {@code false}.
   *
   * <pre class="code">
   * Assert.isTrue(i &gt; 0, () -&gt; "The value '" + i + "' must be greater than zero");
   * </pre>
   *
   * @param expression a boolean expression
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if {@code expression} is {@code false}
   * @since 5.0
   */
  public static void isTrue(final boolean expression, final Supplier<String> messageSupplier) {
    if (!expression) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #isTrue(boolean, String)}
   */
  @Deprecated
  public static void isTrue(final boolean expression) {
    Assert.isTrue(expression, "[Assertion failed] - this expression must be true");
  }

  /**
   * Assert that an object is {@code null}.
   *
   * <pre class="code">
   * Assert.isNull(value, "The value must be null");
   * </pre>
   *
   * @param object the object to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object is not {@code null}
   */
  public static void isNull(@Nullable final Object object, final String message) {
    if (object != null) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that an object is {@code null}.
   *
   * <pre class="code">
   * Assert.isNull(value, () -&gt; "The value '" + value + "' must be null");
   * </pre>
   *
   * @param object the object to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object is not {@code null}
   * @since 5.0
   */
  public static void isNull(@Nullable final Object object, final Supplier<String> messageSupplier) {
    if (object != null) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #isNull(Object, String)}
   */
  @Deprecated
  public static void isNull(@Nullable final Object object) {
    Assert.isNull(object, "[Assertion failed] - the object argument must be null");
  }

  /**
   * Assert that an object is not {@code null}.
   *
   * <pre class="code">
   * Assert.notNull(clazz, "The class must not be null");
   * </pre>
   *
   * @param object the object to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object is {@code null}
   */
  public static void notNull(@Nullable final Object object, final String message) {
    if (object == null) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that an object is not {@code null}.
   *
   * <pre class="code">
   * Assert.notNull(clazz, () -&gt; "The class '" + clazz.getName() + "' must not be null");
   * </pre>
   *
   * @param object the object to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object is {@code null}
   * @since 5.0
   */
  public static void notNull(@Nullable final Object object,
      final Supplier<String> messageSupplier) {
    if (object == null) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #notNull(Object, String)}
   */
  @Deprecated
  public static void notNull(@Nullable final Object object) {
    Assert.notNull(object, "[Assertion failed] - this argument is required; it must not be null");
  }

  /**
   * Assert that the given String is not empty; that is, it must not be {@code null} and not the
   * empty String.
   *
   * <pre class="code">
   * Assert.hasLength(name, "Name must not be empty");
   * </pre>
   *
   * @param text the String to check
   * @param message the exception message to use if the assertion fails
   * @see StringUtils#hasLength
   * @throws IllegalArgumentException if the text is empty
   */
  public static void hasLength(@Nullable final String text, final String message) {
    if (!StringUtils.hasLength(text)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that the given String is not empty; that is, it must not be {@code null} and not the
   * empty String.
   *
   * <pre class="code">
   * Assert.hasLength(name, () -&gt; "Name for account '" + account.getId() + "' must not be empty");
   * </pre>
   *
   * @param text the String to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @see StringUtils#hasLength
   * @throws IllegalArgumentException if the text is empty
   * @since 5.0
   */
  public static void hasLength(@Nullable final String text,
      final Supplier<String> messageSupplier) {
    if (!StringUtils.hasLength(text)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #hasLength(String, String)}
   */
  @Deprecated
  public static void hasLength(@Nullable final String text) {
    Assert.hasLength(text,
        "[Assertion failed] - this String argument must have length; it must not be null or empty");
  }

  /**
   * Assert that the given String contains valid text content; that is, it must not be {@code null}
   * and must contain at least one non-whitespace character.
   *
   * <pre class="code">
   * Assert.hasText(name, "'name' must not be empty");
   * </pre>
   *
   * @param text the String to check
   * @param message the exception message to use if the assertion fails
   * @see StringUtils#hasText
   * @throws IllegalArgumentException if the text does not contain valid text content
   */
  public static void hasText(@Nullable final String text, final String message) {
    if (!StringUtils.hasText(text)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that the given String contains valid text content; that is, it must not be {@code null}
   * and must contain at least one non-whitespace character.
   *
   * <pre class="code">
   * Assert.hasText(name, () -&gt; "Name for account '" + account.getId() + "' must not be empty");
   * </pre>
   *
   * @param text the String to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @see StringUtils#hasText
   * @throws IllegalArgumentException if the text does not contain valid text content
   * @since 5.0
   */
  public static void hasText(@Nullable final String text, final Supplier<String> messageSupplier) {
    if (!StringUtils.hasText(text)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #hasText(String, String)}
   */
  @Deprecated
  public static void hasText(@Nullable final String text) {
    Assert.hasText(text,
        "[Assertion failed] - this String argument must have text; it must not be null, empty, or blank");
  }

  /**
   * Assert that the given text does not contain the given substring.
   *
   * <pre class="code">
   * Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
   * </pre>
   *
   * @param textToSearch the text to search
   * @param substring the substring to find within the text
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the text contains the substring
   */
  public static void doesNotContain(@Nullable final String textToSearch, final String substring,
      final String message) {
    if (StringUtils.hasLength(textToSearch) && StringUtils.hasLength(substring)
        && textToSearch.contains(substring)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that the given text does not contain the given substring.
   *
   * <pre class="code">
   * Assert.doesNotContain(name, forbidden, () -&gt; "Name must not contain '" + forbidden + "'");
   * </pre>
   *
   * @param textToSearch the text to search
   * @param substring the substring to find within the text
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the text contains the substring
   * @since 5.0
   */
  public static void doesNotContain(@Nullable final String textToSearch, final String substring,
      final Supplier<String> messageSupplier) {
    if (StringUtils.hasLength(textToSearch) && StringUtils.hasLength(substring)
        && textToSearch.contains(substring)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #doesNotContain(String, String, String)}
   */
  @Deprecated
  public static void doesNotContain(@Nullable final String textToSearch, final String substring) {
    Assert.doesNotContain(textToSearch, substring,
        () -> "[Assertion failed] - this String argument must not contain the substring ["
            + substring + "]");
  }

  /**
   * Assert that an array contains elements; that is, it must not be {@code null} and must contain
   * at least one element.
   *
   * <pre class="code">
   * Assert.notEmpty(array, "The array must contain elements");
   * </pre>
   *
   * @param array the array to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object array is {@code null} or contains no elements
   */
  public static void notEmpty(@Nullable final Object[] array, final String message) {
    if (ObjectUtils.isEmpty(array)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that an array contains elements; that is, it must not be {@code null} and must contain
   * at least one element.
   *
   * <pre class="code">
   * Assert.notEmpty(array, () -&gt; "The " + arrayType + " array must contain elements");
   * </pre>
   *
   * @param array the array to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object array is {@code null} or contains no elements
   * @since 5.0
   */
  public static void notEmpty(@Nullable final Object[] array,
      final Supplier<String> messageSupplier) {
    if (ObjectUtils.isEmpty(array)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #notEmpty(Object[], String)}
   */
  @Deprecated
  public static void notEmpty(@Nullable final Object[] array) {
    Assert.notEmpty(array,
        "[Assertion failed] - this array must not be empty: it must contain at least 1 element");
  }

  /**
   * Assert that an array contains no {@code null} elements.
   * <p>
   * Note: Does not complain if the array is empty!
   *
   * <pre class="code">
   * Assert.noNullElements(array, "The array must contain non-null elements");
   * </pre>
   *
   * @param array the array to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object array contains a {@code null} element
   */
  public static void noNullElements(@Nullable final Object[] array, final String message) {
    if (array != null) {
      for (final Object element : array) {
        if (element == null) {
          throw new IllegalArgumentException(message);
        }
      }
    }
  }

  /**
   * Assert that an array contains no {@code null} elements.
   * <p>
   * Note: Does not complain if the array is empty!
   *
   * <pre class="code">
   * Assert.noNullElements(array, () -&gt; "The " + arrayType + " array must contain non-null elements");
   * </pre>
   *
   * @param array the array to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the object array contains a {@code null} element
   * @since 5.0
   */
  public static void noNullElements(@Nullable final Object[] array,
      final Supplier<String> messageSupplier) {
    if (array != null) {
      for (final Object element : array) {
        if (element == null) {
          throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
        }
      }
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #noNullElements(Object[], String)}
   */
  @Deprecated
  public static void noNullElements(@Nullable final Object[] array) {
    Assert.noNullElements(array,
        "[Assertion failed] - this array must not contain any null elements");
  }

  /**
   * Assert that a collection contains elements; that is, it must not be {@code null} and must
   * contain at least one element.
   *
   * <pre class="code">
   * Assert.notEmpty(collection, "Collection must contain elements");
   * </pre>
   *
   * @param collection the collection to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the collection is {@code null} or contains no elements
   */
  public static void notEmpty(@Nullable final Collection<?> collection, final String message) {
    if (CollectionUtils.isEmpty(collection)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that a collection contains elements; that is, it must not be {@code null} and must
   * contain at least one element.
   *
   * <pre class="code">
   * Assert.notEmpty(collection, () -&gt; "The " + collectionType + " collection must contain elements");
   * </pre>
   *
   * @param collection the collection to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the collection is {@code null} or contains no elements
   * @since 5.0
   */
  public static void notEmpty(@Nullable final Collection<?> collection,
      final Supplier<String> messageSupplier) {
    if (CollectionUtils.isEmpty(collection)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #notEmpty(Collection, String)}
   */
  @Deprecated
  public static void notEmpty(@Nullable final Collection<?> collection) {
    Assert.notEmpty(collection,
        "[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
  }

  /**
   * Assert that a Map contains entries; that is, it must not be {@code null} and must contain at
   * least one entry.
   *
   * <pre class="code">
   * Assert.notEmpty(map, "Map must contain entries");
   * </pre>
   *
   * @param map the map to check
   * @param message the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the map is {@code null} or contains no entries
   */
  public static void notEmpty(@Nullable final Map<?, ?> map, final String message) {
    if (CollectionUtils.isEmpty(map)) {
      throw new IllegalArgumentException(message);
    }
  }

  /**
   * Assert that a Map contains entries; that is, it must not be {@code null} and must contain at
   * least one entry.
   *
   * <pre class="code">
   * Assert.notEmpty(map, () -&gt; "The " + mapType + " map must contain entries");
   * </pre>
   *
   * @param map the map to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails
   * @throws IllegalArgumentException if the map is {@code null} or contains no entries
   * @since 5.0
   */
  public static void notEmpty(@Nullable final Map<?, ?> map,
      final Supplier<String> messageSupplier) {
    if (CollectionUtils.isEmpty(map)) {
      throw new IllegalArgumentException(Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * @deprecated as of 4.3.7, in favor of {@link #notEmpty(Map, String)}
   */
  @Deprecated
  public static void notEmpty(@Nullable final Map<?, ?> map) {
    Assert.notEmpty(map,
        "[Assertion failed] - this map must not be empty; it must contain at least one entry");
  }

  /**
   * Assert that the provided object is an instance of the provided class.
   *
   * <pre class="code">
   * Assert.instanceOf(Foo.class, foo, "Foo expected");
   * </pre>
   *
   * @param type the type to check against
   * @param obj the object to check
   * @param message a message which will be prepended to provide further context. If it is empty or
   *        ends in ":" or ";" or "," or ".", a full exception message will be appended. If it ends
   *        in a space, the name of the offending object's type will be appended. In any other case,
   *        a ":" with a space and the name of the offending object's type will be appended.
   * @throws IllegalArgumentException if the object is not an instance of type
   */
  @GwtIncompatible("incompatible method")
  public static void isInstanceOf(final Class<?> type, @Nullable final Object obj,
      final String message) {
    Assert.notNull(type, "Type to check against must not be null");
    if (!type.isInstance(obj)) {
      Assert.instanceCheckFailed(type, obj, message);
    }
  }

  /**
   * Assert that the provided object is an instance of the provided class.
   *
   * <pre class="code">
   * Assert.instanceOf(Foo.class, foo, () -&gt; "Processing " + Foo.class.getSimpleName() + ":");
   * </pre>
   *
   * @param type the type to check against
   * @param obj the object to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails. See
   *        {@link #isInstanceOf(Class, Object, String)} for details.
   * @throws IllegalArgumentException if the object is not an instance of type
   * @since 5.0
   */
  @GwtIncompatible("incompatible method")
  public static void isInstanceOf(final Class<?> type, @Nullable final Object obj,
      final Supplier<String> messageSupplier) {
    Assert.notNull(type, "Type to check against must not be null");
    if (!type.isInstance(obj)) {
      Assert.instanceCheckFailed(type, obj, Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * Assert that the provided object is an instance of the provided class.
   *
   * <pre class="code">
   * Assert.instanceOf(Foo.class, foo);
   * </pre>
   *
   * @param type the type to check against
   * @param obj the object to check
   * @throws IllegalArgumentException if the object is not an instance of type
   */
  @GwtIncompatible("incompatible method")
  public static void isInstanceOf(final Class<?> type, @Nullable final Object obj) {
    Assert.isInstanceOf(type, obj, "");
  }

  /**
   * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}.
   *
   * <pre class="code">
   * Assert.isAssignable(Number.class, myClass, "Number expected");
   * </pre>
   *
   * @param superType the super type to check against
   * @param subType the sub type to check
   * @param message a message which will be prepended to provide further context. If it is empty or
   *        ends in ":" or ";" or "," or ".", a full exception message will be appended. If it ends
   *        in a space, the name of the offending sub type will be appended. In any other case, a
   *        ":" with a space and the name of the offending sub type will be appended.
   * @throws IllegalArgumentException if the classes are not assignable
   */
  @GwtIncompatible("incompatible method")
  public static void isAssignable(final Class<?> superType, @Nullable final Class<?> subType,
      final String message) {
    Assert.notNull(superType, "Super type to check against must not be null");
    if (subType == null || !superType.isAssignableFrom(subType)) {
      Assert.assignableCheckFailed(superType, subType, message);
    }
  }

  /**
   * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}.
   *
   * <pre class="code">
   * Assert.isAssignable(Number.class, myClass, () -&gt; "Processing " + myAttributeName + ":");
   * </pre>
   *
   * @param superType the super type to check against
   * @param subType the sub type to check
   * @param messageSupplier a supplier for the exception message to use if the assertion fails. See
   *        {@link #isAssignable(Class, Class, String)} for details.
   * @throws IllegalArgumentException if the classes are not assignable
   * @since 5.0
   */
  @GwtIncompatible("incompatible method")
  public static void isAssignable(final Class<?> superType, @Nullable final Class<?> subType,
      final Supplier<String> messageSupplier) {
    Assert.notNull(superType, "Super type to check against must not be null");
    if (subType == null || !superType.isAssignableFrom(subType)) {
      Assert.assignableCheckFailed(superType, subType, Assert.nullSafeGet(messageSupplier));
    }
  }

  /**
   * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}.
   *
   * <pre class="code">
   * Assert.isAssignable(Number.class, myClass);
   * </pre>
   *
   * @param superType the super type to check
   * @param subType the sub type to check
   * @throws IllegalArgumentException if the classes are not assignable
   */
  @GwtIncompatible("incompatible method")
  public static void isAssignable(final Class<?> superType, final Class<?> subType) {
    Assert.isAssignable(superType, subType, "");
  }


  private static void instanceCheckFailed(final Class<?> type, @Nullable final Object obj,
      @Nullable final String msg) {
    final String className = obj != null ? obj.getClass().getName() : "null";
    String result = "";
    boolean defaultMessage = true;
    if (StringUtils.hasLength(msg)) {
      if (Assert.endsWithSeparator(msg)) {
        result = msg + " ";
      } else {
        result = Assert.messageWithTypeName(msg, className);
        defaultMessage = false;
      }
    }
    if (defaultMessage) {
      result = result + "Object of class [" + className + "] must be an instance of " + type;
    }
    throw new IllegalArgumentException(result);
  }

  private static void assignableCheckFailed(final Class<?> superType,
      @Nullable final Class<?> subType, @Nullable final String msg) {
    String result = "";
    boolean defaultMessage = true;
    if (StringUtils.hasLength(msg)) {
      if (Assert.endsWithSeparator(msg)) {
        result = msg + " ";
      } else {
        result = Assert.messageWithTypeName(msg, subType);
        defaultMessage = false;
      }
    }
    if (defaultMessage) {
      result = result + subType + " is not assignable to " + superType;
    }
    throw new IllegalArgumentException(result);
  }

  private static boolean endsWithSeparator(final String msg) {
    return msg.endsWith(":") || msg.endsWith(";") || msg.endsWith(",") || msg.endsWith(".");
  }

  private static String messageWithTypeName(final String msg, @Nullable final Object typeName) {
    return msg + (msg.endsWith(" ") ? "" : ": ") + typeName;
  }

  @Nullable
  private static String nullSafeGet(@Nullable final Supplier<String> messageSupplier) {
    return messageSupplier != null ? messageSupplier.get() : null;
  }

}
