public abstract class Assert extends Object
Useful for identifying programmer errors early and clearly at runtime.
For example, if the contract of a public method states it does not
allow null
arguments, Assert
can be used to validate that
contract. Doing this clearly indicates a contract violation when it
occurs and protects the class's invariants.
Typically used to validate method arguments rather than configuration properties, to check for cases that are usually programmer errors rather than configuration errors. In contrast to configuration initialization code, there is usually no point in falling back to defaults in such methods.
This class is similar to JUnit's assertion library. If an argument value is
deemed invalid, an IllegalArgumentException
is thrown (typically).
For example:
Assert.notNull(clazz, "The class must not be null"); Assert.isTrue(i > 0, "The value must be greater than zero");
Mainly for internal use within the framework; consider
Apache's Commons Lang
for a more comprehensive suite of String
utilities.
Constructor and Description |
---|
Assert() |
Modifier and Type | Method and Description |
---|---|
static void |
doesNotContain(String textToSearch,
String substring)
Deprecated.
as of 4.3.7, in favor of
doesNotContain(String, String, String) |
static void |
doesNotContain(String textToSearch,
String substring,
String message)
Assert that the given text does not contain the given substring.
|
static void |
doesNotContain(String textToSearch,
String substring,
Supplier<String> messageSupplier)
Assert that the given text does not contain the given substring.
|
static void |
hasLength(String text)
Deprecated.
as of 4.3.7, in favor of
hasLength(String, String) |
static void |
hasLength(String text,
String message)
Assert that the given String is not empty; that is,
it must not be
null and not the empty String. |
static void |
hasLength(String text,
Supplier<String> messageSupplier)
Assert that the given String is not empty; that is,
it must not be
null and not the empty String. |
static void |
hasText(String text)
Deprecated.
as of 4.3.7, in favor of
hasText(String, String) |
static void |
hasText(String text,
String message)
Assert that the given String contains valid text content; that is, it must not
be
null and must contain at least one non-whitespace character. |
static void |
hasText(String text,
Supplier<String> messageSupplier)
Assert that the given String contains valid text content; that is, it must not
be
null and must contain at least one non-whitespace character. |
static void |
isAssignable(Class<?> superType,
Class<?> subType)
Assert that
superType.isAssignableFrom(subType) is true . |
static void |
isAssignable(Class<?> superType,
Class<?> subType,
String message)
Assert that
superType.isAssignableFrom(subType) is true . |
static void |
isAssignable(Class<?> superType,
Class<?> subType,
Supplier<String> messageSupplier)
Assert that
superType.isAssignableFrom(subType) is true . |
static void |
isInstanceOf(Class<?> type,
Object obj)
Assert that the provided object is an instance of the provided class.
|
static void |
isInstanceOf(Class<?> type,
Object obj,
String message)
Assert that the provided object is an instance of the provided class.
|
static void |
isInstanceOf(Class<?> type,
Object obj,
Supplier<String> messageSupplier)
Assert that the provided object is an instance of the provided class.
|
static void |
isNull(Object object)
Deprecated.
as of 4.3.7, in favor of
isNull(Object, String) |
static void |
isNull(Object object,
String message)
Assert that an object is
null . |
static void |
isNull(Object object,
Supplier<String> messageSupplier)
Assert that an object is
null . |
static void |
isTrue(boolean expression)
Deprecated.
as of 4.3.7, in favor of
isTrue(boolean, String) |
static void |
isTrue(boolean expression,
String message)
Assert a boolean expression, throwing an
IllegalArgumentException
if the expression evaluates to false . |
static void |
isTrue(boolean expression,
Supplier<String> messageSupplier)
Assert a boolean expression, throwing an
IllegalArgumentException
if the expression evaluates to false . |
static void |
noNullElements(Collection<?> collection,
String message)
Assert that a collection contains no
null elements. |
static void |
noNullElements(Collection<?> collection,
Supplier<String> messageSupplier)
Assert that a collection contains no
null elements. |
static void |
noNullElements(Object[] array)
Deprecated.
as of 4.3.7, in favor of
noNullElements(Object[], String) |
static void |
noNullElements(Object[] array,
String message)
Assert that an array contains no
null elements. |
static void |
noNullElements(Object[] array,
Supplier<String> messageSupplier)
Assert that an array contains no
null elements. |
static void |
notEmpty(Collection<?> collection)
Deprecated.
as of 4.3.7, in favor of
notEmpty(Collection, String) |
static void |
notEmpty(Collection<?> collection,
String message)
Assert that a collection contains elements; that is, it must not be
null and must contain at least one element. |
static void |
notEmpty(Collection<?> collection,
Supplier<String> messageSupplier)
Assert that a collection contains elements; that is, it must not be
null and must contain at least one element. |
static void |
notEmpty(Map<?,?> map)
Deprecated.
as of 4.3.7, in favor of
notEmpty(Map, String) |
static void |
notEmpty(Map<?,?> map,
String message)
Assert that a Map contains entries; that is, it must not be
null
and must contain at least one entry. |
static void |
notEmpty(Map<?,?> map,
Supplier<String> messageSupplier)
Assert that a Map contains entries; that is, it must not be
null
and must contain at least one entry. |
static void |
notEmpty(Object[] array)
Deprecated.
as of 4.3.7, in favor of
notEmpty(Object[], String) |
static void |
notEmpty(Object[] array,
String message)
Assert that an array contains elements; that is, it must not be
null and must contain at least one element. |
static void |
notEmpty(Object[] array,
Supplier<String> messageSupplier)
Assert that an array contains elements; that is, it must not be
null and must contain at least one element. |
static void |
notNull(Object object)
Deprecated.
as of 4.3.7, in favor of
notNull(Object, String) |
static void |
notNull(Object object,
String message)
Assert that an object is not
null . |
static void |
notNull(Object object,
Supplier<String> messageSupplier)
Assert that an object is not
null . |
static void |
state(boolean expression)
Deprecated.
as of 4.3.7, in favor of
state(boolean, String) |
static void |
state(boolean expression,
String message)
Assert a boolean expression, throwing an
IllegalStateException
if the expression evaluates to false . |
static void |
state(boolean expression,
Supplier<String> messageSupplier)
Assert a boolean expression, throwing an
IllegalStateException
if the expression evaluates to false . |
public static void state(boolean expression, String message)
IllegalStateException
if the expression evaluates to false
.
Call isTrue(boolean, java.lang.String)
if you wish to throw an IllegalArgumentException
on an assertion failure.
Assert.state(id == null, "The id property must not already be initialized");
expression
- a boolean expressionmessage
- the exception message to use if the assertion failsIllegalStateException
- if expression
is false
public static void state(boolean expression, Supplier<String> messageSupplier)
IllegalStateException
if the expression evaluates to false
.
Call isTrue(boolean, java.lang.String)
if you wish to throw an IllegalArgumentException
on an assertion failure.
Assert.state(id == null, () -> "ID for " + entity.getName() + " must not already be initialized");
expression
- a boolean expressionmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalStateException
- if expression
is false
@Deprecated public static void state(boolean expression)
state(boolean, String)
IllegalStateException
if the expression evaluates to false
.public static void isTrue(boolean expression, String message)
IllegalArgumentException
if the expression evaluates to false
.
Assert.isTrue(i > 0, "The value must be greater than zero");
expression
- a boolean expressionmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if expression
is false
public static void isTrue(boolean expression, Supplier<String> messageSupplier)
IllegalArgumentException
if the expression evaluates to false
.
Assert.isTrue(i > 0, () -> "The value '" + i + "' must be greater than zero");
expression
- a boolean expressionmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if expression
is false
@Deprecated public static void isTrue(boolean expression)
isTrue(boolean, String)
IllegalArgumentException
if the expression evaluates to false
.public static void isNull(@Nullable Object object, String message)
null
.
Assert.isNull(value, "The value must be null");
object
- the object to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the object is not null
public static void isNull(@Nullable Object object, Supplier<String> messageSupplier)
null
.
Assert.isNull(value, () -> "The value '" + value + "' must be null");
object
- the object to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the object is not null
@Deprecated public static void isNull(@Nullable Object object)
isNull(Object, String)
null
.public static void notNull(@Nullable Object object, String message)
null
.
Assert.notNull(clazz, "The class must not be null");
object
- the object to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the object is null
public static void notNull(@Nullable Object object, Supplier<String> messageSupplier)
null
.
Assert.notNull(clazz, () -> "The class '" + clazz.getName() + "' must not be null");
object
- the object to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the object is null
@Deprecated public static void notNull(@Nullable Object object)
notNull(Object, String)
null
.public static void hasLength(@Nullable String text, String message)
null
and not the empty String.
Assert.hasLength(name, "Name must not be empty");
text
- the String to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the text is emptyStringUtils.hasLength(java.lang.CharSequence)
public static void hasLength(@Nullable String text, Supplier<String> messageSupplier)
null
and not the empty String.
Assert.hasLength(name, () -> "Name for account '" + account.getId() + "' must not be empty");
text
- the String to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the text is emptyStringUtils.hasLength(java.lang.CharSequence)
@Deprecated public static void hasLength(@Nullable String text)
hasLength(String, String)
null
and not the empty String.public static void hasText(@Nullable String text, String message)
null
and must contain at least one non-whitespace character.
Assert.hasText(name, "'name' must not be empty");
text
- the String to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the text does not contain valid text contentStringUtils.hasText(java.lang.CharSequence)
public static void hasText(@Nullable String text, Supplier<String> messageSupplier)
null
and must contain at least one non-whitespace character.
Assert.hasText(name, () -> "Name for account '" + account.getId() + "' must not be empty");
text
- the String to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the text does not contain valid text contentStringUtils.hasText(java.lang.CharSequence)
@Deprecated public static void hasText(@Nullable String text)
hasText(String, String)
null
and must contain at least one non-whitespace character.public static void doesNotContain(@Nullable String textToSearch, String substring, String message)
Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
textToSearch
- the text to searchsubstring
- the substring to find within the textmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the text contains the substringpublic static void doesNotContain(@Nullable String textToSearch, String substring, Supplier<String> messageSupplier)
Assert.doesNotContain(name, forbidden, () -> "Name must not contain '" + forbidden + "'");
textToSearch
- the text to searchsubstring
- the substring to find within the textmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the text contains the substring@Deprecated public static void doesNotContain(@Nullable String textToSearch, String substring)
doesNotContain(String, String, String)
public static void notEmpty(@Nullable Object[] array, String message)
null
and must contain at least one element.
Assert.notEmpty(array, "The array must contain elements");
array
- the array to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the object array is null
or contains no elementspublic static void notEmpty(@Nullable Object[] array, Supplier<String> messageSupplier)
null
and must contain at least one element.
Assert.notEmpty(array, () -> "The " + arrayType + " array must contain elements");
array
- the array to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the object array is null
or contains no elements@Deprecated public static void notEmpty(@Nullable Object[] array)
notEmpty(Object[], String)
null
and must contain at least one element.public static void noNullElements(@Nullable Object[] array, String message)
null
elements.
Note: Does not complain if the array is empty!
Assert.noNullElements(array, "The array must contain non-null elements");
array
- the array to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the object array contains a null
elementpublic static void noNullElements(@Nullable Object[] array, Supplier<String> messageSupplier)
null
elements.
Note: Does not complain if the array is empty!
Assert.noNullElements(array, () -> "The " + arrayType + " array must contain non-null elements");
array
- the array to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the object array contains a null
element@Deprecated public static void noNullElements(@Nullable Object[] array)
noNullElements(Object[], String)
null
elements.public static void notEmpty(@Nullable Collection<?> collection, String message)
null
and must contain at least one element.
Assert.notEmpty(collection, "Collection must contain elements");
collection
- the collection to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the collection is null
or
contains no elementspublic static void notEmpty(@Nullable Collection<?> collection, Supplier<String> messageSupplier)
null
and must contain at least one element.
Assert.notEmpty(collection, () -> "The " + collectionType + " collection must contain elements");
collection
- the collection to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the collection is null
or
contains no elements@Deprecated public static void notEmpty(@Nullable Collection<?> collection)
notEmpty(Collection, String)
null
and must contain at least one element.public static void noNullElements(@Nullable Collection<?> collection, String message)
null
elements.
Note: Does not complain if the collection is empty!
Assert.noNullElements(collection, "Collection must contain non-null elements");
collection
- the collection to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the collection contains a null
elementpublic static void noNullElements(@Nullable Collection<?> collection, Supplier<String> messageSupplier)
null
elements.
Note: Does not complain if the collection is empty!
Assert.noNullElements(collection, () -> "Collection " + collectionName + " must contain non-null elements");
collection
- the collection to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the collection contains a null
elementpublic static void notEmpty(@Nullable Map<?,?> map, String message)
null
and must contain at least one entry.
Assert.notEmpty(map, "Map must contain entries");
map
- the map to checkmessage
- the exception message to use if the assertion failsIllegalArgumentException
- if the map is null
or contains no entriespublic static void notEmpty(@Nullable Map<?,?> map, Supplier<String> messageSupplier)
null
and must contain at least one entry.
Assert.notEmpty(map, () -> "The " + mapType + " map must contain entries");
map
- the map to checkmessageSupplier
- a supplier for the exception message to use if the
assertion failsIllegalArgumentException
- if the map is null
or contains no entries@Deprecated public static void notEmpty(@Nullable Map<?,?> map)
notEmpty(Map, String)
null
and must contain at least one entry.public static void isInstanceOf(Class<?> type, @Nullable Object obj, String message)
Assert.instanceOf(Foo.class, foo, "Foo expected");
type
- the type to check againstobj
- the object to checkmessage
- a message which will be prepended to provide further context.
If it is empty or ends in ":" or ";" or "," or ".", a full exception message
will be appended. If it ends in a space, the name of the offending object's
type will be appended. In any other case, a ":" with a space and the name
of the offending object's type will be appended.IllegalArgumentException
- if the object is not an instance of typepublic static void isInstanceOf(Class<?> type, @Nullable Object obj, Supplier<String> messageSupplier)
Assert.instanceOf(Foo.class, foo, () -> "Processing " + Foo.class.getSimpleName() + ":");
type
- the type to check againstobj
- the object to checkmessageSupplier
- a supplier for the exception message to use if the
assertion fails. See isInstanceOf(Class, Object, String)
for details.IllegalArgumentException
- if the object is not an instance of typepublic static void isInstanceOf(Class<?> type, @Nullable Object obj)
Assert.instanceOf(Foo.class, foo);
type
- the type to check againstobj
- the object to checkIllegalArgumentException
- if the object is not an instance of typepublic static void isAssignable(Class<?> superType, @Nullable Class<?> subType, String message)
superType.isAssignableFrom(subType)
is true
.
Assert.isAssignable(Number.class, myClass, "Number expected");
superType
- the super type to check againstsubType
- the sub type to checkmessage
- a message which will be prepended to provide further context.
If it is empty or ends in ":" or ";" or "," or ".", a full exception message
will be appended. If it ends in a space, the name of the offending sub type
will be appended. In any other case, a ":" with a space and the name of the
offending sub type will be appended.IllegalArgumentException
- if the classes are not assignablepublic static void isAssignable(Class<?> superType, @Nullable Class<?> subType, Supplier<String> messageSupplier)
superType.isAssignableFrom(subType)
is true
.
Assert.isAssignable(Number.class, myClass, () -> "Processing " + myAttributeName + ":");
superType
- the super type to check againstsubType
- the sub type to checkmessageSupplier
- a supplier for the exception message to use if the
assertion fails. See isAssignable(Class, Class, String)
for details.IllegalArgumentException
- if the classes are not assignablepublic static void isAssignable(Class<?> superType, Class<?> subType)
superType.isAssignableFrom(subType)
is true
.
Assert.isAssignable(Number.class, myClass);
superType
- the super type to checksubType
- the sub type to checkIllegalArgumentException
- if the classes are not assignable