Package org.bardframework.commons.utils

Class ObjectUtils

java.lang.Object
org.bardframework.commons.utils.ObjectUtils
public final class ObjectUtils extends Object

Operations on Object.

This class tries to handle null input gracefully. An exception will generally not be thrown for a null input. Each method documents its behaviour in more detail.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    ObjectUtils.Null
    Class used as a null placeholder where null has another meaning.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final ObjectUtils.Null
    NULL
    Singleton used as a null placeholder where null has another meaning.

  • Method Summary

    Modifier and Type
    Method
    Description
    static <A, O extends A>
    A[]
    addObjectToArray(A[] array, O obj)
    Append the given object to the given array, returning a new array consisting of the input array contents plus the given object.
    static boolean
    allNotNull(Object... values)
    Checks if all values in the array are not nulls.
    static boolean
    anyNotNull(Object... values)
    Checks if any value in the given array is not null.
    static <E extends Enum<?>>
    E
    caseInsensitiveValueOf(E[] enumValues, String constant)
    Case insensitive alternative to Enum.valueOf(Class, String).
    static <T> T
    clone(T obj)
    Clone an object.
    static <T> T
    cloneIfPossible(T obj)
    Clone an object if possible.
    static <T extends Comparable<? super T>>
    int
    compare(T c1, T c2)
    Null safe comparison of Comparables.
    static <T extends Comparable<? super T>>
    int
    compare(T c1, T c2, boolean nullGreater)
    Null safe comparison of Comparables.
    static boolean
    CONST(boolean v)
    This method returns the provided value unchanged.
    static byte
    CONST(byte v)
    This method returns the provided value unchanged.
    static char
    CONST(char v)
    This method returns the provided value unchanged.
    static double
    CONST(double v)
    This method returns the provided value unchanged.
    static float
    CONST(float v)
    This method returns the provided value unchanged.
    static int
    CONST(int v)
    This method returns the provided value unchanged.
    static long
    CONST(long v)
    This method returns the provided value unchanged.
    static short
    CONST(short v)
    This method returns the provided value unchanged.
    static <T> T
    CONST(T v)
    This method returns the provided value unchanged.
    static byte
    CONST_BYTE(int v)
    This method returns the provided value unchanged.
    static short
    CONST_SHORT(int v)
    This method returns the provided value unchanged.
    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.
    static boolean
    containsConstant(Enum<?>[] enumValues, String constant, boolean caseSensitive)
    Check whether the given array of enum constants contains a constant with the given name.
    static boolean
    containsElement(Object[] array, Object element)
    Check whether the given array contains the given element.
    static <T> T
    defaultIfNull(T object, T defaultValue)
    Returns a default value if the object passed is null.
    static <T> T
    firstNonNull(T... values)
    Returns the first value in the array which is not null.
    static String
    getDisplayString(Object obj)
    Return a content-based String representation if obj is not null; otherwise returns an empty String.
    static String
    getIdentityHexString(Object obj)
    Return a hex String form of an object's identity hash code.
    static void
    identityToString(Appendable appendable, Object object)
    Appends the toString that would be produced by Object if a class did not override toString itself.
    static String
    identityToString(Object object)
    Gets the toString that would be produced by Object if a class did not override toString itself.
    static void
    identityToString(StringBuffer buffer, Object object)
    Appends the toString that would be produced by Object if a class did not override toString itself.
    static void
    identityToString(StringBuilder builder, Object object)
    Appends the toString that would be produced by Object if a class did not override toString itself.
    static boolean
    isArray(Object obj)
    Determine whether the given object is an array: either an Object array or a primitive array.
    static boolean
    isCheckedException(Throwable ex)
    Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.
    static boolean
    isCompatibleWithThrowsClause(Throwable ex, Class<?>... declaredExceptions)
    Check whether the given exception is compatible with the specified exception types, as declared in a throws clause.
    static boolean
    isEmpty(Object object)
    Checks if an Object is empty or null.
    static boolean
    isEmpty(Object[] array)
    Determine whether the given array is empty: i.e.
    static boolean
    isNotEmpty(Object object)
    Checks if an Object is not empty and not null.
    static <T extends Comparable<? super T>>
    T
    max(T... values)
    Null safe comparison of Comparables.
    static <T extends Comparable<? super T>>
    T
    min(T... values)
    Null safe comparison of Comparables.
    static String
    nullSafeClassName(Object obj)
    Determine the class name for the given object.
    static boolean
    nullSafeEquals(Object o1, 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(Object obj)
    Return as hash code for the given object; typically the value of Object#hashCode()}.
    static int
    nullSafeHashCode(Object[] array)
    Return a hash code based on the contents of the specified array.
    static String
    nullSafeToString(boolean[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(byte[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(char[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(double[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(float[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(int[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(long[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(short[] array)
    Return a String representation of the contents of the specified array.
    static String
    nullSafeToString(Object obj)
    Return a String representation of the specified Object.
    static String
    nullSafeToString(Object[] array)
    Return a String representation of the contents of the specified array.
    static Object[]
    toObjectArray(Object source)
    Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).
    static Object
    unwrapOptional(Object obj)
    Unwrap the given object which is potentially a Optional.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • NULL

      public static final ObjectUtils.Null NULL

      Singleton used as a null placeholder where null has another meaning.

      For example, in a HashMap the HashMap.get(Object) method returns null if the Map contains null or if there is no matching key. The Null placeholder can be used to distinguish between these two cases.

      Another example is Hashtable, where null cannot be stored.

      This instance is Serializable.

  • 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

    • isCompatibleWithThrowsClause

      public static boolean isCompatibleWithThrowsClause(Throwable ex, 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

      public static boolean isArray(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(Object[] array)
      Determine whether the given array is empty: i.e. null or of zero length.
      Parameters:
      array - the array to check

    • unwrapOptional

      public static Object unwrapOptional(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

    • containsElement

      public static boolean containsElement(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(A[] array, 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)

    • toObjectArray

      public static Object[] toObjectArray(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:
      IllegalArgumentException - if the parameter is not an array

    • nullSafeEquals

      public static boolean nullSafeEquals(Object o1, 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(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.

    • nullSafeHashCode

      public static int nullSafeHashCode(Object[] array)
      Return a hash code based on the contents of the specified array. If array is null, this method returns 0.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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(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

    • nullSafeClassName

      public static String nullSafeClassName(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(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 String nullSafeToString(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(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(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(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(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(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(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(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(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

    • isEmpty

      public static boolean isEmpty(Object object)

      Checks if an Object is empty or null.

      The following types are supported:
      • CharSequence: Considered empty if its length is zero.
      • Array: Considered empty if its length is zero.
      • Collection: Considered empty if it has zero elements.
      • Map: Considered empty if it has zero key-value mappings.
       ObjectUtils.isEmpty(null)             = true
 ObjectUtils.isEmpty("")               = true
 ObjectUtils.isEmpty("ab")             = false
 ObjectUtils.isEmpty(new int[]{})      = true
 ObjectUtils.isEmpty(new int[]{1,2,3}) = false
 ObjectUtils.isEmpty(1234)             = false
      Parameters:
      object - the Object to test, may be null
      Returns:
      true if the object has a supported type and is empty or null, false otherwise

    • isNotEmpty

      public static boolean isNotEmpty(Object object)

      Checks if an Object is not empty and not null.

      The following types are supported:
      • CharSequence: Considered empty if its length is zero.
      • Array: Considered empty if its length is zero.
      • Collection: Considered empty if it has zero elements.
      • Map: Considered empty if it has zero key-value mappings.
       ObjectUtils.isNotEmpty(null)             = false
 ObjectUtils.isNotEmpty("")               = false
 ObjectUtils.isNotEmpty("ab")             = true
 ObjectUtils.isNotEmpty(new int[]{})      = false
 ObjectUtils.isNotEmpty(new int[]{1,2,3}) = true
 ObjectUtils.isNotEmpty(1234)             = true
      Parameters:
      object - the Object to test, may be null
      Returns:
      true if the object has an unsupported type or is not empty and not null, false otherwise

    • defaultIfNull

      public static <T> T defaultIfNull(T object, T defaultValue)

      Returns a default value if the object passed is null.

       ObjectUtils.defaultIfNull(null, null)      = null
 ObjectUtils.defaultIfNull(null, "")        = ""
 ObjectUtils.defaultIfNull(null, "zz")      = "zz"
 ObjectUtils.defaultIfNull("abc", *)        = "abc"
 ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE
      Type Parameters:
      T - the type of the object
      Parameters:
      object - the Object to test, may be null
      defaultValue - the default value to return, may be null
      Returns:
      object if it is not null, defaultValue otherwise

    • firstNonNull

      @SafeVarargs public static <T> T firstNonNull(T... values)

      Returns the first value in the array which is not null. If all the values are null or the array is null or empty then null is returned.

       ObjectUtils.firstNonNull(null, null)      = null
 ObjectUtils.firstNonNull(null, "")        = ""
 ObjectUtils.firstNonNull(null, null, "")  = ""
 ObjectUtils.firstNonNull(null, "zz")      = "zz"
 ObjectUtils.firstNonNull("abc", *)        = "abc"
 ObjectUtils.firstNonNull(null, "xyz", *)  = "xyz"
 ObjectUtils.firstNonNull(Boolean.TRUE, *) = Boolean.TRUE
 ObjectUtils.firstNonNull()                = null
      Type Parameters:
      T - the component type of the array
      Parameters:
      values - the values to test, may be null or empty
      Returns:
      the first value from values which is not null, or null if there are no non-null values

    • anyNotNull

      public static boolean anyNotNull(Object... values)
      Checks if any value in the given array is not null. If all the values are null or the array is null or empty then false is returned. Otherwise true is returned. 
       ObjectUtils.anyNotNull(*)                = true
 ObjectUtils.anyNotNull(*, null)          = true
 ObjectUtils.anyNotNull(null, *)          = true
 ObjectUtils.anyNotNull(null, null, *, *) = true
 ObjectUtils.anyNotNull(null)             = false
 ObjectUtils.anyNotNull(null, null)       = false
      Parameters:
      values - the values to test, may be null or empty
      Returns:
      true if there is at least one non-null value in the array, false if all values in the array are nulls. If the array is null or empty false is also returned.

    • allNotNull

      public static boolean allNotNull(Object... values)
      Checks if all values in the array are not nulls. If any value is null or the array is null then false is returned. If all elements in array are not null or the array is empty (contains no elements) true is returned. 
       ObjectUtils.allNotNull(*)             = true
 ObjectUtils.allNotNull(*, *)          = true
 ObjectUtils.allNotNull(null)          = false
 ObjectUtils.allNotNull(null, null)    = false
 ObjectUtils.allNotNull(null, *)       = false
 ObjectUtils.allNotNull(*, null)       = false
 ObjectUtils.allNotNull(*, *, null, *) = false
      Parameters:
      values - the values to test, may be null or empty
      Returns:
      false if there is at least one null value in the array or the array is null, true if all values in the array are not nulls or array contains no elements.

    • identityToString

      public static String identityToString(Object object)

      Gets the toString that would be produced by Object if a class did not override toString itself. null will return null.

       ObjectUtils.identityToString(null)         = null
 ObjectUtils.identityToString("")           = "java.lang.String@1e23"
 ObjectUtils.identityToString(Boolean.TRUE) = "java.lang.Boolean@7fa"
      Parameters:
      object - the object to create a toString for, may be null
      Returns:
      the default toString text, or null if null passed in

    • identityToString

      public static void identityToString(Appendable appendable, Object object) throws IOException

      Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters. 

       ObjectUtils.identityToString(appendable, "")            = appendable.append("java.lang.String@1e23"
 ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa"
 ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa")
      Parameters:
      appendable - the appendable to append to
      object - the object to create a toString for
      Throws:
      IOException - if an I/O error occurs

    • identityToString

      public static void identityToString(StringBuffer buffer, Object object)

      Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters. 

       ObjectUtils.identityToString(buf, "")            = buf.append("java.lang.String@1e23"
 ObjectUtils.identityToString(buf, Boolean.TRUE)  = buf.append("java.lang.Boolean@7fa"
 ObjectUtils.identityToString(buf, Boolean.TRUE)  = buf.append("java.lang.Boolean@7fa")
      Parameters:
      buffer - the buffer to append to
      object - the object to create a toString for

    • identityToString

      public static void identityToString(StringBuilder builder, Object object)

      Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters. 

       ObjectUtils.identityToString(builder, "")            = builder.append("java.lang.String@1e23"
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa"
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa")
      Parameters:
      builder - the builder to append to
      object - the object to create a toString for

    • min

      @SafeVarargs public static <T extends Comparable<? super T>> T min(T... values)

      Null safe comparison of Comparables.

      Type Parameters:
      T - type of the values processed by this method
      Parameters:
      values - the set of comparable values, may be null
      Returns:
      • If any objects are non-null and unequal, the lesser object.
      • If all objects are non-null and equal, the first.
      • If any of the comparables are null, the lesser of the non-null objects.
      • If all the comparables are null, null is returned.

    • max

      @SafeVarargs public static <T extends Comparable<? super T>> T max(T... values)

      Null safe comparison of Comparables.

      Type Parameters:
      T - type of the values processed by this method
      Parameters:
      values - the set of comparable values, may be null
      Returns:
      • If any objects are non-null and unequal, the greater object.
      • If all objects are non-null and equal, the first.
      • If any of the comparables are null, the greater of the non-null objects.
      • If all the comparables are null, null is returned.

    • compare

      public static <T extends Comparable<? super T>> int compare(T c1, T c2)

      Null safe comparison of Comparables. null is assumed to be less than a non-null value.

      Type Parameters:
      T - type of the values processed by this method
      Parameters:
      c1 - the first comparable, may be null
      c2 - the second comparable, may be null
      Returns:
      a negative value if c1 < c2, zero if c1 = c2 and a positive value if c1 > c2

    • compare

      public static <T extends Comparable<? super T>> int compare(T c1, T c2, boolean nullGreater)

      Null safe comparison of Comparables.

      Type Parameters:
      T - type of the values processed by this method
      Parameters:
      c1 - the first comparable, may be null
      c2 - the second comparable, may be null
      nullGreater - if true null is considered greater than a non-null value or if false null is considered less than a Non-null value
      Returns:
      a negative value if c1 < c2, zero if c1 = c2 and a positive value if c1 > c2

    • clone

      public static <T> T clone(T obj)

      Clone an object.

      Type Parameters:
      T - the type of the object
      Parameters:
      obj - the object to clone, null returns null
      Returns:
      the clone if the object implements Cloneable otherwise null
      Throws:
      IllegalStateException - if the object is cloneable and the clone operation fails

    • cloneIfPossible

      public static <T> T cloneIfPossible(T obj)

      Clone an object if possible.

      This method is similar to clone(Object), but will return the provided instance as the return value instead of null if the instance is not cloneable. This is more convenient if the caller uses different implementations (e.g. of a service) and some of the implementations do not allow concurrent processing or have state. In such cases the implementation can simply provide a proper clone implementation and the caller's code does not have to change.

      Type Parameters:
      T - the type of the object
      Parameters:
      obj - the object to clone, null returns null
      Returns:
      the clone if the object implements Cloneable otherwise the object itself
      Throws:
      IllegalStateException - if the object is cloneable and the clone operation fails

    • CONST

      public static boolean CONST(boolean v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static boolean MAGIC_FLAG = ObjectUtils.CONST(true);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the boolean value to return
      Returns:
      the boolean v, unchanged

    • CONST

      public static byte CONST(byte v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static byte MAGIC_BYTE = ObjectUtils.CONST((byte) 127);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the byte value to return
      Returns:
      the byte v, unchanged

    • CONST_BYTE

      public static byte CONST_BYTE(int v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static byte MAGIC_BYTE = ObjectUtils.CONST_BYTE(127);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the byte literal (as an int) value to return
      Returns:
      the byte v, unchanged
      Throws:
      IllegalArgumentException - if the value passed to v is larger than a byte, that is, smaller than -128 or larger than 127.

    • CONST

      public static char CONST(char v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static char MAGIC_CHAR = ObjectUtils.CONST('a');
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the char value to return
      Returns:
      the char v, unchanged

    • CONST

      public static short CONST(short v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static short MAGIC_SHORT = ObjectUtils.CONST((short) 123);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the short value to return
      Returns:
      the short v, unchanged

    • CONST_SHORT

      public static short CONST_SHORT(int v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static short MAGIC_SHORT = ObjectUtils.CONST_SHORT(127);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the short literal (as an int) value to return
      Returns:
      the byte v, unchanged
      Throws:
      IllegalArgumentException - if the value passed to v is larger than a short, that is, smaller than -32768 or larger than 32767.

    • CONST

      public static int CONST(int v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static int MAGIC_INT = ObjectUtils.CONST(123);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the int value to return
      Returns:
      the int v, unchanged

    • CONST

      public static long CONST(long v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static long MAGIC_LONG = ObjectUtils.CONST(123L);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the long value to return
      Returns:
      the long v, unchanged

    • CONST

      public static float CONST(float v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static float MAGIC_FLOAT = ObjectUtils.CONST(1.0f);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the float value to return
      Returns:
      the float v, unchanged

    • CONST

      public static double CONST(double v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static double MAGIC_DOUBLE = ObjectUtils.CONST(1.0);
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Parameters:
      v - the double value to return
      Returns:
      the double v, unchanged

    • CONST

      public static <T> T CONST(T v)
      This method returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g., 
           public final static String MAGIC_STRING = ObjectUtils.CONST("abc");
      This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.
      Type Parameters:
      T - the Object type
      Parameters:
      v - the genericized Object value to return (typically a String).
      Returns:
      the genericized Object v, unchanged (typically a String).