Package io.permazen

Class Util

java.lang.Object

io.permazen.Util

public final class Util
extends Object

Various utility routines.

Method Summary

Modifier and Type	Method	Description
static TypeToken<?>	findErasureDifference(TypeToken<?> genType, Collection<? extends TypeToken<?>> candidates)	Check whether a generic type and its erased equivalent match the same set of candidate types.
static PermazenField	findField(PermazenClass<?> pclass, String fieldName)	Identify the named field in the given PermazenClass.
static PermazenField	findField(PermazenClass<?> pclass, String fieldName, Boolean expectSubField)	Identify the named field in the given PermazenClass.
static PermazenSimpleField	findSimpleField(PermazenClass<?> pclass, String fieldName)	Identify the named simple field in the given PermazenClass.
static <A extends Annotation> A	getAnnotation(AnnotatedElement element, Class<A> annotationType)	Find the annotation on the given element.
static Type	getTypeParameter(Type type, int index)	Get the n'th generic type parameter.
static boolean	hasDefaultValidationAnnotation(AnnotatedElement obj)	Determine whether the given object has any JSR 303 annotation(s) defining validation constraints in the default group.
static AnnotatedElement	hasValidation(Class<?> type)	Determine if any JSR 303 validation annotations are present on the given type itself or any of its methods (public methods only).
static boolean	hasValidationAnnotation(AnnotatedElement obj)	Determine whether the given object has any JSR 303 annotation(s).
static Object	invoke(Method method, Object target, Object... params)	Invoke method via reflection and re-throw any checked exception wrapped in an PermazenException.
static boolean	isAnyGroupBeingValidated(Class<?>[] constraintGroups, Class<?>[] validationGroups)	Determine if a constraint whose groups() contain the given constraint groups should be applied when validating with the given validation groups.
static boolean	isGroupBeingValidated(Class<?> constraintGroup, Class<?>[] validationGroups)	Determine if a constraint whose groups() contain the given constraint group should be applied when validating with the given validation groups.
static boolean	requiresDefaultValidation(Class<?> type)	Determine if instances of the given type require any validation under the default validation group.
static boolean	requiresDefaultValidation(Method method)	Determine if the given getter method, or any method it overrides, has a JSR 303 validation constraint applicable under the default validation group.
static <A, B> Converter<B,A>	reverse(Converter<A,B> converter)	Return the reverse of the given Converter, treating a null converter as if it were the identity.
static <T> Stream<T>	streamOf(T obj)	Substitute for Stream.of(Object).

Methods inherited from class java.lang.Object

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

Method Details

getAnnotation

public static <A extends Annotation> A getAnnotation(AnnotatedElement element,
 Class<A> annotationType)

Find the annotation on the given element.

If spring-core is available on the classpath, the implementation in AnnotationScanner utilizes Spring's AnnotatedElementUtils.getMergedAnnotation(AnnotatedElement, Class) method to find annotations that are either present or meta-present on the element, and includes support for annotation attribute overrides; otherwise, it just invokes AnnotatedElement.getAnnotation(Class).

Type Parameters:

A - annotation type

Parameters:

element - element with annotation or meta-present annotation

annotationType - type of the annotation to find

Returns:

the annotation found, or null if not found

hasValidation

public static AnnotatedElement hasValidation(Class<?> type)

Determine if any JSR 303 validation annotations are present on the given type itself or any of its methods (public methods only).

Parameters:

type - object type

Returns:

a non-null object with JSR 303 validation requirements, or null if none found

Throws:

IllegalArgumentException - if type is null

requiresDefaultValidation

public static boolean requiresDefaultValidation(Class<?> type)

Determine if instances of the given type require any validation under the default validation group.

This will be true if type or any of its declared methods has a JSR 303 (public methods only) or @OnValidate annotation, or if any of its super-types requires validation.

Parameters:

type - object type

Returns:

true if type has any validation requirements

Throws:

IllegalArgumentException - if type is null

See Also:

• ValidationMode

requiresDefaultValidation

public static boolean requiresDefaultValidation(Method method)

Determine if the given getter method, or any method it overrides, has a JSR 303 validation constraint applicable under the default validation group.

Parameters:

method - annotated method

Returns:

true if obj has one or more JSR 303 annotations

Throws:

IllegalArgumentException - if method is null

hasDefaultValidationAnnotation

public static boolean hasDefaultValidationAnnotation(AnnotatedElement obj)

Determine whether the given object has any JSR 303 annotation(s) defining validation constraints in the default group.

Parameters:

obj - annotated element

Returns:

true if obj has one or more JSR 303 default validation constraint annotations

Throws:

IllegalArgumentException - if obj is null

hasValidationAnnotation

public static boolean hasValidationAnnotation(AnnotatedElement obj)

Determine whether the given object has any JSR 303 annotation(s).

Parameters:

obj - annotated element

Returns:

true if obj has one or more JSR 303 validation constraint annotations

Throws:

IllegalArgumentException - if obj is null

isGroupBeingValidated

public static boolean isGroupBeingValidated(Class<?> constraintGroup,
 Class<?>[] validationGroups)

Determine if a constraint whose groups() contain the given constraint group should be applied when validating with the given validation groups.

Parameters:

constraintGroup - validation group associated with a validation constraint

validationGroups - groups for which validation is being performed

Returns:

whether to apply the validation constraint

Throws:

IllegalArgumentException - if any null values are encountered

isAnyGroupBeingValidated

public static boolean isAnyGroupBeingValidated(Class<?>[] constraintGroups,
 Class<?>[] validationGroups)

Determine if a constraint whose groups() contain the given constraint groups should be applied when validating with the given validation groups.

Parameters:

constraintGroups - validation groups associated with a validation constraint

validationGroups - groups for which validation is being performed

Returns:

whether to apply the validation constraint

Throws:

IllegalArgumentException - if any null values are encountered

findField

public static PermazenField findField(PermazenClass<?> pclass,
 String fieldName)

Identify the named field in the given PermazenClass.

The field may be specified by name like "myfield" or by name and storage ID like "myfield#1234".

To specify a sub-field of a complex field, qualify it with the parent field like "mymap.key".

This method is equivalent to findField(pclass, fieldName, null).

Parameters:

pclass - containing object type

fieldName - field name

Returns:

resulting PermazenField, or null if no such field is found in pclass

Throws:

IllegalArgumentException - if fieldName is ambiguous or invalid

IllegalArgumentException - if pclass or fieldName is null

findSimpleField

public static PermazenSimpleField findSimpleField(PermazenClass<?> pclass,
 String fieldName)

Identify the named simple field in the given PermazenClass.

The field may be specified by name like "myfield" or by name and storage ID like "myfield#1234".

To specify a sub-field of a complex field, qualify it with the parent field like "mymap.key".

This method is equivalent to findField(pclass, fieldName, true) plus filtering out non-PermazenSimpleFields.

Parameters:

pclass - containing object type

fieldName - field name

Returns:

resulting PermazenField, or null if no such field is found in pclass

Throws:

IllegalArgumentException - if fieldName is ambiguous or invalid

IllegalArgumentException - if pclass or fieldName is null

findField

public static PermazenField findField(PermazenClass<?> pclass,
 String fieldName,
 Boolean expectSubField)

Identify the named field in the given PermazenClass.

The field may be specified by name like "myfield" or by name and storage ID like "myfield#1234".

To specify a sub-field of a complex field, qualify it with the parent field like "mymap.key".

The expectSubField parameter controls what happens when a complex field is matched. If true, then either a sub-field must be specified, or else the complex field must have only one sub-field and then that sub-field is assumed. If false, it is an error to specify a sub-field of a complex field. If null, either is OK.

Parameters:

pclass - containing object type

fieldName - field name

expectSubField - true if the field should be a complex sub-field instead of a complex field, false if field should not be complex field instead of a complex sub-field, or null for don't care

Returns:

resulting PermazenField, or null if no such field is found in pclass

Throws:

IllegalArgumentException - if fieldName is ambiguous or invalid

IllegalArgumentException - if pclass or fieldName is null

findErasureDifference

public static TypeToken<?> findErasureDifference(TypeToken<?> genType,
 Collection<? extends TypeToken<?>> candidates)

Check whether a generic type and its erased equivalent match the same set of candidate types.

Parameters:

genType - parameter generic type

candidates - possible candidates for parameter

Returns:

mismatching candidate, or null if generic and erased match the same candidates

streamOf

public static <T> Stream<T> streamOf(T obj)

Substitute for Stream.of(Object).

Permazen needs this method because the v1.6 class files we generate don't support invoking static methods on interfaces.

getTypeParameter

public static Type getTypeParameter(Type type,
 int index)

Get the n'th generic type parameter.

Parameters:

type - parameterized generic type

index - type parameter index (zero based)

Returns:

type parameter at index

Throws:

IllegalArgumentException - if type is not a parameterized type with more than index type variables

invoke

public static Object invoke(Method method,
 Object target,
 Object... params)

Invoke method via reflection and re-throw any checked exception wrapped in an PermazenException.

Parameters:

method - method to invoke

target - instance, or null if method is static

params - method parameters

Returns:

method return value

Throws:

PermazenException - if an error occurs

reverse

public static <A,
B> Converter<B,A> reverse(Converter<A,B> converter)

Return the reverse of the given Converter, treating a null converter as if it were the identity.

Parameters:

converter - original converter, or null for the identity conversion

Returns:

reversed converter