Package org.springframework.util

Class ObjectUtils

java.lang.Object
org.springframework.util.ObjectUtils
public abstract class ObjectUtils extends Object
Miscellaneous object utility methods.

Mainly for internal use within the framework.

Thanks to Alex Ruiz for contributing several enhancements to this class!

Since:
19.03.2004
Author:
Juergen Hoeller, Keith Donald, Rod Johnson, Rob Harrop, Chris Beams, Sam Brannen
See Also:

  • Constructor Details

    • ObjectUtils

      public ObjectUtils()

  • Method Details

    • isCheckedException

      public static boolean isCheckedException(Throwable ex)
      Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.
      Parameters:
      ex - the throwable to check
      Returns:
      whether the throwable is a checked exception
      See Also:

    • isCompatibleWithThrowsClause

      public static boolean isCompatibleWithThrowsClause(Throwable ex, @Nullable Class<?>... declaredExceptions)
      Check whether the given exception is compatible with the specified exception types, as declared in a throws clause.
      Parameters:
      ex - the exception to check
      declaredExceptions - the exception types declared in the throws clause
      Returns:
      whether the given exception is compatible

    • isArray

      @Contract("null -> false") public static boolean isArray(@Nullable Object obj)
      Determine whether the given object is an array: either an Object array or a primitive array.
      Parameters:
      obj - the object to check

    • isEmpty

      @Contract("null -> true") public static boolean isEmpty(@Nullable Object[] array)
      Determine whether the given array is empty: i.e. null or of zero length.
      Parameters:
      array - the array to check
      See Also:

    • isEmpty

      public static boolean isEmpty(@Nullable Object obj)
      Determine whether the given object is empty.

      This method supports the following object types.

      If the given object is non-null and not one of the aforementioned supported types, this method returns false.

      Parameters:
      obj - the object to check
      Returns:
      true if the object is null or empty
      Since:
      4.2
      See Also:

    • unwrapOptional

      @Nullable public static Object unwrapOptional(@Nullable Object obj)
      Unwrap the given object which is potentially a Optional.
      Parameters:
      obj - the candidate object
      Returns:
      either the value held within the Optional, null if the Optional is empty, or simply the given object as-is
      Since:
      5.0

    • containsElement

      public static boolean containsElement(@Nullable Object[] array, Object element)
      Check whether the given array contains the given element.
      Parameters:
      array - the array to check (may be null, in which case the return value will always be false)
      element - the element to check for
      Returns:
      whether the element has been found in the given array

    • containsConstant

      public static boolean containsConstant(Enum<?>[] enumValues, String constant)
      Check whether the given array of enum constants contains a constant with the given name, ignoring case when determining a match.
      Parameters:
      enumValues - the enum values to check, typically obtained via MyEnum.values()
      constant - the constant name to find (must not be null or empty string)
      Returns:
      whether the constant has been found in the given array

    • containsConstant

      public static boolean containsConstant(Enum<?>[] enumValues, String constant, boolean caseSensitive)
      Check whether the given array of enum constants contains a constant with the given name.
      Parameters:
      enumValues - the enum values to check, typically obtained via MyEnum.values()
      constant - the constant name to find (must not be null or empty string)
      caseSensitive - whether case is significant in determining a match
      Returns:
      whether the constant has been found in the given array

    • caseInsensitiveValueOf

      public static <E extends Enum<?>> E caseInsensitiveValueOf(E[] enumValues, String constant)
      Case insensitive alternative to Enum.valueOf(Class, String).
      Type Parameters:
      E - the concrete Enum type
      Parameters:
      enumValues - the array of all Enum constants in question, usually per Enum.values()
      constant - the constant to get the enum value of
      Throws:
      IllegalArgumentException - if the given constant is not found in the given array of enum values. Use containsConstant(Enum[], String) as a guard to avoid this exception.

    • addObjectToArray

      public static <A, O extends A> A[] addObjectToArray(@Nullable A[] array, @Nullable O obj)
      Append the given object to the given array, returning a new array consisting of the input array contents plus the given object.
      Parameters:
      array - the array to append to (can be null)
      obj - the object to append
      Returns:
      the new array (of the same component type; never null)

    • addObjectToArray

      public static <A, O extends A> A[] addObjectToArray(@Nullable A[] array, @Nullable O obj, int position)
      Add the given object to the given array at the specified position, returning a new array consisting of the input array contents plus the given object.
      Parameters:
      array - the array to add to (can be null)
      obj - the object to append
      position - the position at which to add the object
      Returns:
      the new array (of the same component type; never null)
      Since:
      6.0

    • toObjectArray

      public static Object[] toObjectArray(@Nullable Object source)
      Convert the given array (which may be a primitive array) to an object array (if necessary, to an array of primitive wrapper objects).

      A null source value or empty primitive array will be converted to an empty Object array.

      Parameters:
      source - the (potentially primitive) array
      Returns:
      the corresponding object array (never null)
      Throws:
      IllegalArgumentException - if the parameter is not an array

    • nullSafeEquals

      @Contract("null, null -> true; null, _ -> false; _, null -> false") public static boolean nullSafeEquals(@Nullable Object o1, @Nullable Object o2)
      Determine if the given objects are equal, returning true if both are null or false if only one is null.

      Compares arrays with Arrays.equals, performing an equality check based on the array elements rather than the array reference.

      Parameters:
      o1 - first Object to compare
      o2 - second Object to compare
      Returns:
      whether the given objects are equal
      See Also:

    • nullSafeHash

      public static int nullSafeHash(@Nullable Object... elements)
      Return a hash code for the given elements, delegating to nullSafeHashCode(Object) for each element. Contrary to Objects.hash(Object...), this method can handle an element that is an array.
      Parameters:
      elements - the elements to be hashed
      Returns:
      a hash value of the elements
      Since:
      6.1

    • nullSafeHashCode

      public static int nullSafeHashCode(@Nullable Object obj)
      Return a hash code for the given object; typically the value of Object#hashCode()}. If the object is an array, this method will delegate to any of the Arrays.hashCode methods. If the object is null, this method returns 0.
      See Also:

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable Object[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(Object[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable boolean[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(boolean[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable byte[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(byte[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable char[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(char[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable double[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(double[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable float[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(float[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable int[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(int[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable long[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(long[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • nullSafeHashCode

      @Deprecated(since="6.1") public static int nullSafeHashCode(@Nullable short[] array)
      Deprecated.
      as of 6.1 in favor of Arrays.hashCode(short[])
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • identityToString

      public static String identityToString(@Nullable Object obj)
      Return a String representation of an object's overall identity.
      Parameters:
      obj - the object (may be null)
      Returns:
      the object's identity as String representation, or an empty String if the object was null

    • getIdentityHexString

      public static String getIdentityHexString(Object obj)
      Return a hex String form of an object's identity hash code.
      Parameters:
      obj - the object
      Returns:
      the object's identity code in hex notation

    • getDisplayString

      public static String getDisplayString(@Nullable Object obj)
      Return a content-based String representation if obj is not null; otherwise returns an empty String.

      Differs from nullSafeToString(Object) in that it returns an empty String rather than "null" for a null value.

      Parameters:
      obj - the object to build a display String for
      Returns:
      a display String representation of obj
      See Also:

    • nullSafeClassName

      public static String nullSafeClassName(@Nullable Object obj)
      Determine the class name for the given object.

      Returns a "null" String if obj is null.

      Parameters:
      obj - the object to introspect (may be null)
      Returns:
      the corresponding class name

    • nullSafeToString

      public static String nullSafeToString(@Nullable Object obj)
      Return a String representation of the specified Object.

      Builds a String representation of the contents in case of an array. Returns a "null" String if obj is null.

      Parameters:
      obj - the object to build a String representation for
      Returns:
      a String representation of obj
      See Also:

    • nullSafeToString

      public static String nullSafeToString(@Nullable Object[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable boolean[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable byte[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable char[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable double[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable float[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable int[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable long[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeToString

      public static String nullSafeToString(@Nullable short[] array)
      Return a String representation of the contents of the specified array.

      The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.

      Parameters:
      array - the array to build a String representation for
      Returns:
      a String representation of array

    • nullSafeConciseToString

      public static String nullSafeConciseToString(@Nullable Object obj)
      Generate a null-safe, concise string representation of the supplied object as described below.

      Favor this method over nullSafeToString(Object) when you need the length of the generated string to be limited.

      Returns:

      • "null" if obj is null
      • "Optional.empty" if obj is an empty Optional
      • "Optional[<concise-string>]" if obj is a non-empty Optional, where <concise-string> is the result of invoking this method on the object contained in the Optional
      • "{}" if obj is an empty array
      • "{...}" if obj is a Map or a non-empty array
      • "[...]" if obj is a Collection
      • Class name if obj is a Class
      • Charset name if obj is a Charset
      • TimeZone ID if obj is a TimeZone
      • Zone ID if obj is a ZoneId
      • Potentially truncated string if obj is a String or CharSequence
      • Potentially truncated string if obj is a simple value type whose toString() method returns a non-null value
      • Otherwise, a string representation of the object's type name concatenated with "@" and a hex string form of the object's identity hash code

      In the context of this method, a simple value type is any of the following: primitive wrapper (excluding Void), Enum, Number, Date, Temporal, File, Path, URI, URL, InetAddress, Currency, Locale, UUID, Pattern.

      Parameters:
      obj - the object to build a string representation for
      Returns:
      a concise string representation of the supplied object
      Since:
      5.3.27
      See Also: