Package org.apache.commons.lang3

Class ObjectUtils

  • public class ObjectUtils
extends java.lang.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 behavior in more detail.

    #ThreadSafe#

    Since:
    1.0

    • 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 ObjectUtils.Null NULL
      Singleton used as a null placeholder where null has another meaning.

    • Constructor Summary

      Constructors 
      Constructor Description
      ObjectUtils()
      ObjectUtils instances should NOT be constructed in standard programming.

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static boolean allNotNull​(java.lang.Object... values)
      Checks if all values in the array are not nulls.
      static boolean allNull​(java.lang.Object... values)
      Checks if all values in the given array are null.
      static boolean anyNotNull​(java.lang.Object... values)
      Checks if any value in the given array is not null.
      static boolean anyNull​(java.lang.Object... values)
      Checks if any value in the given array is null.
      static <T> T clone​(T obj)
      Clone an object.
      static <T> T cloneIfPossible​(T obj)
      Clone an object if possible.
      static <T extends java.lang.Comparable<? super T>>
      int      		 compare​(T c1, T c2)
      Null safe comparison of Comparables.
      static <T extends java.lang.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 <T> T defaultIfNull​(T object, T defaultValue)
      Returns a default value if the object passed is null.
      static boolean equals​(java.lang.Object object1, java.lang.Object object2)
      Deprecated.
      this method has been replaced by java.util.Objects.equals(Object, Object) in Java 7 and will be removed from future releases.
      static <T> T firstNonNull​(T... values)
      Returns the first value in the array which is not null.
      static <T> T getFirstNonNull​(java.util.function.Supplier<T>... suppliers)
      Executes the given suppliers in order and returns the first return value where a value other than null is returned.
      static <T> T getIfNull​(T object, java.util.function.Supplier<T> defaultSupplier)
      Returns the given object is it is non-null, otherwise returns the Supplier's Supplier.get() value.
      static int hashCode​(java.lang.Object obj)
      Deprecated.
      this method has been replaced by java.util.Objects.hashCode(Object) in Java 7 and will be removed in future releases
      static int hashCodeMulti​(java.lang.Object... objects)
      Deprecated.
      this method has been replaced by java.util.Objects.hash(Object...) in Java 7 and will be removed in future releases.
      static void identityToString​(java.lang.Appendable appendable, java.lang.Object object)
      Appends the toString that would be produced by Object if a class did not override toString itself.
      static java.lang.String identityToString​(java.lang.Object object)
      Gets the toString that would be produced by Object if a class did not override toString itself.
      static void identityToString​(java.lang.StringBuffer buffer, java.lang.Object object)
      Appends the toString that would be produced by Object if a class did not override toString itself.
      static void identityToString​(java.lang.StringBuilder builder, java.lang.Object object)
      Appends the toString that would be produced by Object if a class did not override toString itself.
      static void identityToString​(StrBuilder builder, java.lang.Object object)
      Deprecated.
      as of 3.6, because StrBuilder was moved to commons-text, use one of the other identityToString methods instead
      static boolean isEmpty​(java.lang.Object object)
      Checks if an Object is empty or null.
      static boolean isNotEmpty​(java.lang.Object object)
      Checks if an Object is not empty and not null.
      static <T extends java.lang.Comparable<? super T>>
      T      		 max​(T... values)
      Null safe comparison of Comparables.
      static <T> T median​(java.util.Comparator<T> comparator, T... items)
      Find the "best guess" middle value among comparables.
      static <T extends java.lang.Comparable<? super T>>
      T      		 median​(T... items)
      Find the "best guess" middle value among comparables.
      static <T extends java.lang.Comparable<? super T>>
      T      		 min​(T... values)
      Null safe comparison of Comparables.
      static boolean notEqual​(java.lang.Object object1, java.lang.Object object2)
      Compares two objects for inequality, where either one or both objects may be null.
      static <T> T requireNonEmpty​(T obj)
      Checks that the specified object reference is not null or empty per isEmpty(Object).
      static <T> T requireNonEmpty​(T obj, java.lang.String message)
      Checks that the specified object reference is not null or empty per isEmpty(Object).
      static java.lang.String toString​(java.lang.Object obj)
      Deprecated.
      this method has been replaced by java.util.Objects.toString(Object) in Java 7 and will be removed in future releases.
      static java.lang.String toString​(java.lang.Object obj, java.lang.String nullStr)
      Deprecated.
      this method has been replaced by java.util.Objects.toString(Object, String) in Java 7 and will be removed in future releases.
      static java.lang.String toString​(java.lang.Object obj, java.util.function.Supplier<java.lang.String> supplier)
      Gets the toString of an Object returning a specified text if null input.
      static void wait​(java.lang.Object obj, java.time.Duration duration)
      Calls Object.wait(long, int) for the given Duration.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • 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(java.lang.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.

    • Constructor Detail

      • ObjectUtils

        public ObjectUtils()

        ObjectUtils instances should NOT be constructed in standard programming. Instead, the static methods on the class should be used, such as ObjectUtils.defaultIfNull("a","b");.

        This constructor is public to permit tools that require a JavaBean instance to operate.

    • Method Detail

      • allNotNull

        public static boolean allNotNull​(java.lang.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.
        Since:
        3.5

      • allNull

        public static boolean allNull​(java.lang.Object... values)
        Checks if all values in the given array are null.

        If all the values are null or the array is null or empty, then true is returned, otherwise false is returned. 

         ObjectUtils.allNull(*)                = false
 ObjectUtils.allNull(*, null)          = false
 ObjectUtils.allNull(null, *)          = false
 ObjectUtils.allNull(null, null, *, *) = false
 ObjectUtils.allNull(null)             = true
 ObjectUtils.allNull(null, null)       = true
        Parameters:
        values - the values to test, may be null or empty
        Returns:
        true if all values in the array are nulls, false if there is at least one non-null value in the array.
        Since:
        3.11

      • anyNotNull

        public static boolean anyNotNull​(java.lang.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.
        Since:
        3.5

      • anyNull

        public static boolean anyNull​(java.lang.Object... values)
        Checks if any value in the given array is null.

        If any of the values are null or the array is null, then true is returned, otherwise false is returned. 

         ObjectUtils.anyNull(*)             = false
 ObjectUtils.anyNull(*, *)          = false
 ObjectUtils.anyNull(null)          = true
 ObjectUtils.anyNull(null, null)    = true
 ObjectUtils.anyNull(null, *)       = true
 ObjectUtils.anyNull(*, null)       = true
 ObjectUtils.anyNull(*, *, null, *) = true
        Parameters:
        values - the values to test, may be null or empty
        Returns:
        true if there is at least one null value in the array, false if all the values are non-null. If the array is null or empty, true is also returned.
        Since:
        3.11

      • 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:
        CloneFailedException - if the object is cloneable and the clone operation fails
        Since:
        3.0

      • 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:
        CloneFailedException - if the object is cloneable and the clone operation fails
        Since:
        3.0

      • compare

        public static <T extends java.lang.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 java.lang.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
        See Also:
        Comparator.compare(Object, Object)

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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
        Since:
        3.2

      • 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).
        Since:
        3.2

      • 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:
        java.lang.IllegalArgumentException - if the value passed to v is larger than a byte, that is, smaller than -128 or larger than 127.
        Since:
        3.2

      • 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:
        java.lang.IllegalArgumentException - if the value passed to v is larger than a short, that is, smaller than -32768 or larger than 32767.
        Since:
        3.2

      • 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 TODO Rename to getIfNull in 4.0

      • equals

        @Deprecated
public static boolean equals​(java.lang.Object object1,
                             java.lang.Object object2)
        Deprecated.
        this method has been replaced by java.util.Objects.equals(Object, Object) in Java 7 and will be removed from future releases.

        Compares two objects for equality, where either one or both objects may be null. 

         ObjectUtils.equals(null, null)                  = true
 ObjectUtils.equals(null, "")                    = false
 ObjectUtils.equals("", null)                    = false
 ObjectUtils.equals("", "")                      = true
 ObjectUtils.equals(Boolean.TRUE, null)          = false
 ObjectUtils.equals(Boolean.TRUE, "true")        = false
 ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE)  = true
 ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
        Parameters:
        object1 - the first object, may be null
        object2 - the second object, may be null
        Returns:
        true if the values of both objects are the same

      • 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
        Since:
        3.0

      • getFirstNonNull

        @SafeVarargs
public static <T> T getFirstNonNull​(java.util.function.Supplier<T>... suppliers)

        Executes the given suppliers in order and returns the first return value where a value other than null is returned. Once a non-null value is obtained, all following suppliers are not executed anymore. If all the return values are null or no suppliers are provided then null is returned. 

         ObjectUtils.firstNonNullLazy(null, () -> null) = null
 ObjectUtils.firstNonNullLazy(() -> null, () -> "") = ""
 ObjectUtils.firstNonNullLazy(() -> "", () -> throw new IllegalStateException()) = ""
 ObjectUtils.firstNonNullLazy(() -> null, () -> "zz) = "zz"
 ObjectUtils.firstNonNullLazy() = null
        Type Parameters:
        T - the type of the return values
        Parameters:
        suppliers - the suppliers returning the values to test. null values are ignored. Suppliers may return null or a value of type @{code T}
        Returns:
        the first return value from suppliers which is not null, or null if there are no non-null values
        Since:
        3.10

      • getIfNull

        public static <T> T getIfNull​(T object,
                              java.util.function.Supplier<T> defaultSupplier)

        Returns the given object is it is non-null, otherwise returns the Supplier's Supplier.get() value.

        The caller responsible for thread-safety and exception handling of default value supplier. 

         ObjectUtils.getIfNull(null, () -> null)     = null
 ObjectUtils.getIfNull(null, null)              = null
 ObjectUtils.getIfNull(null, () -> "")       = ""
 ObjectUtils.getIfNull(null, () -> "zz")     = "zz"
 ObjectUtils.getIfNull("abc", *)                = "abc"
 ObjectUtils.getIfNull(Boolean.TRUE, *)         = Boolean.TRUE
        Type Parameters:
        T - the type of the object
        Parameters:
        object - the Object to test, may be null
        defaultSupplier - the default value to return, may be null
        Returns:
        object if it is not null, defaultValueSupplier.get() otherwise
        Since:
        3.10

      • hashCode

        @Deprecated
public static int hashCode​(java.lang.Object obj)
        Deprecated.
        this method has been replaced by java.util.Objects.hashCode(Object) in Java 7 and will be removed in future releases

        Gets the hash code of an object returning zero when the object is null. 

         ObjectUtils.hashCode(null)   = 0
 ObjectUtils.hashCode(obj)    = obj.hashCode()
        Parameters:
        obj - the object to obtain the hash code of, may be null
        Returns:
        the hash code of the object, or zero if null
        Since:
        2.1

      • hashCodeMulti

        @Deprecated
public static int hashCodeMulti​(java.lang.Object... objects)
        Deprecated.
        this method has been replaced by java.util.Objects.hash(Object...) in Java 7 and will be removed in future releases.

        Gets the hash code for multiple objects.

        This allows a hash code to be rapidly calculated for a number of objects. The hash code for a single object is the not same as hashCode(Object). The hash code for multiple objects is the same as that calculated by an ArrayList containing the specified objects. 

         ObjectUtils.hashCodeMulti()                 = 1
 ObjectUtils.hashCodeMulti((Object[]) null)  = 1
 ObjectUtils.hashCodeMulti(a)                = 31 + a.hashCode()
 ObjectUtils.hashCodeMulti(a,b)              = (31 + a.hashCode()) * 31 + b.hashCode()
 ObjectUtils.hashCodeMulti(a,b,c)            = ((31 + a.hashCode()) * 31 + b.hashCode()) * 31 + c.hashCode()
        Parameters:
        objects - the objects to obtain the hash code of, may be null
        Returns:
        the hash code of the objects, or zero if null
        Since:
        3.0

      • identityToString

        public static void identityToString​(java.lang.Appendable appendable,
                                    java.lang.Object object)
                             throws java.io.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:
        java.io.IOException - if an I/O error occurs.
        Since:
        3.2

      • identityToString

        public static java.lang.String identityToString​(java.lang.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

        @Deprecated
public static void identityToString​(StrBuilder builder,
                                    java.lang.Object object)
        Deprecated.
        as of 3.6, because StrBuilder was moved to commons-text, use one of the other identityToString methods instead

        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
        Since:
        3.2

      • identityToString

        public static void identityToString​(java.lang.StringBuffer buffer,
                                    java.lang.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
        Since:
        2.4

      • identityToString

        public static void identityToString​(java.lang.StringBuilder builder,
                                    java.lang.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
        Since:
        3.2

      • isEmpty

        public static boolean isEmpty​(java.lang.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
        Since:
        3.9

      • isNotEmpty

        public static boolean isNotEmpty​(java.lang.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
        Since:
        3.9

      • max

        @SafeVarargs
public static <T extends java.lang.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.

      • median

        @SafeVarargs
public static <T> T median​(java.util.Comparator<T> comparator,
                           T... items)
        Find the "best guess" middle value among comparables. If there is an even number of total values, the lower of the two middle values will be returned.
        Type Parameters:
        T - type of values processed by this method
        Parameters:
        comparator - to use for comparisons
        items - to compare
        Returns:
        T at middle position
        Throws:
        java.lang.NullPointerException - if items or comparator is null
        java.lang.IllegalArgumentException - if items is empty or contains null values
        Since:
        3.0.1

      • median

        @SafeVarargs
public static <T extends java.lang.Comparable<? super T>> T median​(T... items)
        Find the "best guess" middle value among comparables. If there is an even number of total values, the lower of the two middle values will be returned.
        Type Parameters:
        T - type of values processed by this method
        Parameters:
        items - to compare
        Returns:
        T at middle position
        Throws:
        java.lang.NullPointerException - if items is null
        java.lang.IllegalArgumentException - if items is empty or contains null values
        Since:
        3.0.1

      • min

        @SafeVarargs
public static <T extends java.lang.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.

      • notEqual

        public static boolean notEqual​(java.lang.Object object1,
                               java.lang.Object object2)

        Compares two objects for inequality, where either one or both objects may be null. 

         ObjectUtils.notEqual(null, null)                  = false
 ObjectUtils.notEqual(null, "")                    = true
 ObjectUtils.notEqual("", null)                    = true
 ObjectUtils.notEqual("", "")                      = false
 ObjectUtils.notEqual(Boolean.TRUE, null)          = true
 ObjectUtils.notEqual(Boolean.TRUE, "true")        = true
 ObjectUtils.notEqual(Boolean.TRUE, Boolean.TRUE)  = false
 ObjectUtils.notEqual(Boolean.TRUE, Boolean.FALSE) = true
        Parameters:
        object1 - the first object, may be null
        object2 - the second object, may be null
        Returns:
        false if the values of both objects are the same

      • requireNonEmpty

        public static <T> T requireNonEmpty​(T obj)
        Checks that the specified object reference is not null or empty per isEmpty(Object). Use this method for validation, for example: 
         public Foo(Bar bar) {
        this.bar = Objects.requireNonEmpty(bar);
 }
        Type Parameters:
        T - the type of the reference.
        Parameters:
        obj - the object reference to check for nullity.
        Returns:
        obj if not null.
        Throws:
        java.lang.NullPointerException - if obj is null.
        java.lang.IllegalArgumentException - if obj is empty per isEmpty(Object).
        Since:
        3.12.0
        See Also:
        isEmpty(Object)

      • requireNonEmpty

        public static <T> T requireNonEmpty​(T obj,
                                    java.lang.String message)
        Checks that the specified object reference is not null or empty per isEmpty(Object). Use this method for validation, for example: 
         public Foo(Bar bar) {
        this.bar = Objects.requireNonEmpty(bar, "bar");
 }
        Type Parameters:
        T - the type of the reference.
        Parameters:
        obj - the object reference to check for nullity.
        message - the exception message.
        Returns:
        obj if not null.
        Throws:
        java.lang.NullPointerException - if obj is null.
        java.lang.IllegalArgumentException - if obj is empty per isEmpty(Object).
        Since:
        3.12.0
        See Also:
        isEmpty(Object)

      • toString

        @Deprecated
public static java.lang.String toString​(java.lang.Object obj)
        Deprecated.
        this method has been replaced by java.util.Objects.toString(Object) in Java 7 and will be removed in future releases. Note however that said method will return "null" for null references, while this method returns an empty String. To preserve behavior use java.util.Objects.toString(myObject, "")

        Gets the toString of an Object returning an empty string ("") if null input. 

         ObjectUtils.toString(null)         = ""
 ObjectUtils.toString("")           = ""
 ObjectUtils.toString("bat")        = "bat"
 ObjectUtils.toString(Boolean.TRUE) = "true"
        Parameters:
        obj - the Object to toString, may be null
        Returns:
        the passed in Object's toString, or "" if null input
        Since:
        2.0
        See Also:
        StringUtils.defaultString(String), String.valueOf(Object)

      • toString

        @Deprecated
public static java.lang.String toString​(java.lang.Object obj,
                                        java.lang.String nullStr)
        Deprecated.
        this method has been replaced by java.util.Objects.toString(Object, String) in Java 7 and will be removed in future releases.

        Gets the toString of an Object returning a specified text if null input. 

         ObjectUtils.toString(null, null)           = null
 ObjectUtils.toString(null, "null")         = "null"
 ObjectUtils.toString("", "null")           = ""
 ObjectUtils.toString("bat", "null")        = "bat"
 ObjectUtils.toString(Boolean.TRUE, "null") = "true"
        Parameters:
        obj - the Object to toString, may be null
        nullStr - the String to return if null input, may be null
        Returns:
        the passed in Object's toString, or nullStr if null input
        Since:
        2.0
        See Also:
        StringUtils.defaultString(String,String), String.valueOf(Object)

      • toString

        public static java.lang.String toString​(java.lang.Object obj,
                                        java.util.function.Supplier<java.lang.String> supplier)

        Gets the toString of an Object returning a specified text if null input. 

         ObjectUtils.toString(obj, () -> expensive())
 
         ObjectUtils.toString(null, () -> expensive())         = result of expensive()
 ObjectUtils.toString(null, () -> expensive())         = result of expensive()
 ObjectUtils.toString("", () -> expensive())           = ""
 ObjectUtils.toString("bat", () -> expensive())        = "bat"
 ObjectUtils.toString(Boolean.TRUE, () -> expensive()) = "true"
        Parameters:
        obj - the Object to toString, may be null
        supplier - the Supplier of String used on null input, may be null
        Returns:
        the passed in Object's toString, or nullStr if null input
        Since:
        3.11

      • wait

        public static void wait​(java.lang.Object obj,
                        java.time.Duration duration)
                 throws java.lang.InterruptedException
        Calls Object.wait(long, int) for the given Duration.
        Parameters:
        obj - The receiver of the wait call.
        duration - How long to wait.
        Throws:
        java.lang.IllegalArgumentException - if the timeout duration is negative.
        java.lang.IllegalMonitorStateException - if the current thread is not the owner of the obj's monitor.
        java.lang.InterruptedException - if any thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
        Since:
        3.12.0
        See Also:
        Object.wait(long, int)