Class ObjectUtils


  • public abstract class ObjectUtils
    extends java.lang.Object

    This class is a clone of org.springframework.util.ObjectUtils

    Miscellaneous object utility methods.
    • Constructor Summary

      Constructors 
      Constructor Description
      ObjectUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.String getDisplayString​(java.lang.Object obj)
      Return a content-based String representation if obj is not null; otherwise returns an empty String.
      static boolean isArray​(java.lang.Object obj)
      Determine whether the given object is an array: either an Object array or a primitive array.
      static boolean isEmpty​(java.lang.Object obj)
      Determine whether the given object is empty.
      static boolean isEmpty​(java.lang.Object[] array)
      Determine whether the given array is empty: i.e.
      static java.lang.String nullSafeClassName​(java.lang.Object obj)
      Determine the class name for the given object.
      static boolean nullSafeEquals​(java.lang.Object o1, java.lang.Object o2)
      Determine if the given objects are equal, returning true if both are null or false if only one is null.
      static int nullSafeHashCode​(boolean[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(byte[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(char[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(double[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(float[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(int[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(long[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(short[] array)
      Return a hash code based on the contents of the specified array.
      static int nullSafeHashCode​(java.lang.Object obj)
      Return as hash code for the given object; typically the value of Object#hashCode()}.
      static int nullSafeHashCode​(java.lang.Object[] array)
      Return a hash code based on the contents of the specified array.
      static java.lang.String nullSafeToString​(boolean[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(byte[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(char[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(double[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(float[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(int[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(long[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(short[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.String nullSafeToString​(java.lang.Object obj)
      Return a String representation of the specified Object.
      static java.lang.String nullSafeToString​(java.lang.Object[] array)
      Return a String representation of the contents of the specified array.
      static java.lang.Object[] toObjectArray​(java.lang.Object source)
      Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ObjectUtils

        public ObjectUtils()
    • Method Detail

      • isArray

        public static boolean isArray​(@Nullable
                                      java.lang.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

        public static boolean isEmpty​(@Nullable
                                      java.lang.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(Object)
      • isEmpty

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

        This method supports the following object types.

        • Optional: considered empty if Optional.empty()
        • Array: considered empty if its length is zero
        • CharSequence: considered empty if its length is zero
        • Collection: delegates to Collection.isEmpty()
        • Map: delegates to Map.isEmpty()

        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
        See Also:
        Optional.isPresent(), isEmpty(Object[]), StringUtils.hasLength(CharSequence)
      • toObjectArray

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

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

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

        public static boolean nullSafeEquals​(java.lang.Object o1,
                                             java.lang.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
      • nullSafeHashCode

        public static int nullSafeHashCode​(java.lang.Object obj)
        Return as 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 nullSafeHashCode methods for arrays in this class. If the object is null, this method returns 0.
        Parameters:
        obj - the given object
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(java.lang.Object[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(boolean[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(byte[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(char[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(double[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(float[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(int[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(long[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • nullSafeHashCode

        public static int nullSafeHashCode​(short[] array)
        Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
        Parameters:
        array - the specified array
        Returns:
        a hash code value
      • getDisplayString

        public static java.lang.String getDisplayString​(@Nullable
                                                        java.lang.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:
        nullSafeToString(Object)
      • nullSafeClassName

        public static java.lang.String nullSafeClassName​(@Nullable
                                                         java.lang.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 java.lang.String nullSafeToString​(@Nullable
                                                        java.lang.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
      • nullSafeToString

        public static java.lang.String nullSafeToString​(@Nullable
                                                        java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.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