org.hibernate.validator.internal.util.ReflectionHelper Maven / Gradle / Ivy
/*
* Hibernate Validator, declare and validate application constraints
*
* License: Apache License, Version 2.0
* See the license.txt file in the root directory or .
*/
package org.hibernate.validator.internal.util;
import static org.hibernate.validator.internal.util.CollectionHelper.newHashMap;
import java.lang.invoke.MethodHandles;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.hibernate.validator.internal.util.logging.Log;
import org.hibernate.validator.internal.util.logging.LoggerFactory;
/**
* Some reflection utility methods. Where necessary calls will be performed as {@code PrivilegedAction} which is necessary
* for situations where a security manager is in place.
*
* @author Hardy Ferentschik
* @author Gunnar Morling
* @author Kevin Pollet <[email protected]> (C) 2011 SERLI
* @author Guillaume Smet
*/
public final class ReflectionHelper {
private static final String PROPERTY_ACCESSOR_PREFIX_GET = "get";
private static final String PROPERTY_ACCESSOR_PREFIX_IS = "is";
private static final String PROPERTY_ACCESSOR_PREFIX_HAS = "has";
public static final String[] PROPERTY_ACCESSOR_PREFIXES = {
PROPERTY_ACCESSOR_PREFIX_GET,
PROPERTY_ACCESSOR_PREFIX_IS,
PROPERTY_ACCESSOR_PREFIX_HAS
};
private static final Log LOG = LoggerFactory.make( MethodHandles.lookup() );
private static final Map, Class> PRIMITIVE_TO_WRAPPER_TYPES;
static {
Map, Class> tmpMap = newHashMap( 9 );
tmpMap.put( boolean.class, Boolean.class );
tmpMap.put( char.class, Character.class );
tmpMap.put( double.class, Double.class );
tmpMap.put( float.class, Float.class );
tmpMap.put( long.class, Long.class );
tmpMap.put( int.class, Integer.class );
tmpMap.put( short.class, Short.class );
tmpMap.put( byte.class, Byte.class );
tmpMap.put( Void.TYPE, Void.TYPE );
PRIMITIVE_TO_WRAPPER_TYPES = Collections.unmodifiableMap( tmpMap );
}
private static final Map, Class> WRAPPER_TO_PRIMITIVE_TYPES;
static {
Map, Class> tmpMap = newHashMap( 9 );
tmpMap.put( Boolean.class, boolean.class );
tmpMap.put( Character.class, char.class );
tmpMap.put( Double.class, double.class );
tmpMap.put( Float.class, float.class );
tmpMap.put( Long.class, long.class );
tmpMap.put( Integer.class, int.class );
tmpMap.put( Short.class, short.class );
tmpMap.put( Byte.class, byte.class );
tmpMap.put( Void.TYPE, Void.TYPE );
WRAPPER_TO_PRIMITIVE_TYPES = Collections.unmodifiableMap( tmpMap );
}
/**
* Private constructor in order to avoid instantiation.
*/
private ReflectionHelper() {
}
/**
* Returns the JavaBeans property name of the given member.
*
* For fields, the field name will be returned. For getter methods, the
* decapitalized property name will be returned, with the "get", "is" or "has"
* prefix stripped off. Getter methods are methods
*
*
* - whose name start with "get" and who have a return type but no parameter
* or
* - whose name starts with "is" and who have no parameter and return
* {@code boolean} or
* - whose name starts with "has" and who have no parameter and return
* {@code boolean} (HV-specific, not mandated by JavaBeans spec).
*
*
* @param member The member for which to get the property name.
*
* @return The property name for the given member or {@code null} if the
* member is neither a field nor a getter method according to the
* JavaBeans standard.
*/
public static String getPropertyName(Member member) {
String name = null;
if ( member instanceof Field ) {
name = member.getName();
}
if ( member instanceof Method ) {
String methodName = member.getName();
for ( String prefix : PROPERTY_ACCESSOR_PREFIXES ) {
if ( methodName.startsWith( prefix ) ) {
name = StringHelper.decapitalize( methodName.substring( prefix.length() ) );
}
}
}
return name;
}
/**
* Checks whether the given executable is a valid JavaBeans getter method, which
* is the case if
*
* - its name starts with "get" and it has a return type but no parameter or
* - its name starts with "is", it has no parameter and is returning
* {@code boolean} or
* - its name starts with "has", it has no parameter and is returning
* {@code boolean} (HV-specific, not mandated by JavaBeans spec).
*
*
* @param executable The executable of interest.
*
* @return {@code true}, if the given executable is a JavaBeans getter method,
* {@code false} otherwise.
*/
public static boolean isGetterMethod(Executable executable) {
if ( !( executable instanceof Method ) ) {
return false;
}
Method method = (Method) executable;
if ( method.getParameterTypes().length != 0 ) {
return false;
}
String methodName = method.getName();
// get()
if ( methodName.startsWith( PROPERTY_ACCESSOR_PREFIX_GET ) && method.getReturnType() != void.class ) {
return true;
}
//boolean is()
else if ( methodName.startsWith( PROPERTY_ACCESSOR_PREFIX_IS ) && method.getReturnType() == boolean.class ) {
return true;
}
//boolean has()
else if ( methodName.startsWith( PROPERTY_ACCESSOR_PREFIX_HAS ) && method.getReturnType() == boolean.class ) {
return true;
}
return false;
}
/**
* @param member The {@code Member} instance for which to retrieve the type.
*
* @return Returns the {@code Type} of the given {@code Field} or {@code Method}.
*
* @throws IllegalArgumentException in case {@code member} is not a {@code Field} or {@code Method}.
*/
public static Type typeOf(Member member) {
Type type;
if ( member instanceof Field ) {
type = ( (Field) member ).getGenericType();
}
else if ( member instanceof Method ) {
type = ( (Method) member ).getGenericReturnType();
}
else if ( member instanceof Constructor ) {
type = member.getDeclaringClass();
}
//TODO HV-571 change log method name
else {
throw LOG.getMemberIsNeitherAFieldNorAMethodException( member );
}
if ( type instanceof TypeVariable ) {
type = TypeHelper.getErasedType( type );
}
return type;
}
/**
* Returns the type of the parameter of the given method with the given parameter index.
*
* @param executable The executable of interest.
* @param parameterIndex The index of the parameter for which the type should be returned.
*
* @return The erased type.
*/
public static Type typeOf(Executable executable, int parameterIndex) {
Type[] genericParameterTypes = executable.getGenericParameterTypes();
// getGenericParameterTypes() doesn't return synthetic parameters; in this case fall back to getParameterTypes()
if ( parameterIndex >= genericParameterTypes.length ) {
genericParameterTypes = executable.getParameterTypes();
}
Type type = genericParameterTypes[parameterIndex];
if ( type instanceof TypeVariable ) {
type = TypeHelper.getErasedType( type );
}
return type;
}
public static Object getValue(Field field, Object object) {
try {
return field.get( object );
}
catch (IllegalAccessException e) {
throw LOG.getUnableToAccessMemberException( field.getName(), e );
}
}
public static Object getValue(Method method, Object object) {
try {
return method.invoke( object );
}
catch (IllegalAccessException | InvocationTargetException e) {
throw LOG.getUnableToAccessMemberException( method.getName(), e );
}
}
/**
* Indicates whether the given type represents a collection of elements or not (i.e. whether it is an
* {@code Iterable}, {@code Map} or array type).
*/
public static boolean isCollection(Type type) {
return isIterable( type ) ||
isMap( type ) ||
TypeHelper.isArray( type );
}
/**
* Determines the type of the elements of an {@code Iterable}, array or the value of a {@code Map}.
*/
public static Type getCollectionElementType(Type type) {
Type indexedType = null;
if ( isIterable( type ) && type instanceof ParameterizedType ) {
ParameterizedType paramType = (ParameterizedType) type;
indexedType = paramType.getActualTypeArguments()[0];
}
else if ( isMap( type ) && type instanceof ParameterizedType ) {
ParameterizedType paramType = (ParameterizedType) type;
indexedType = paramType.getActualTypeArguments()[1];
}
else if ( TypeHelper.isArray( type ) ) {
indexedType = TypeHelper.getComponentType( type );
}
return indexedType;
}
/**
* Indicates if the type is considered indexable (ie is a {@code List}, an array or a {@code Map}).
*
* Note that it does not include {@code Set}s as they are not indexable.
*
* @param type the type to inspect.
*
* @return Returns true if the type is indexable.
*/
public static boolean isIndexable(Type type) {
return isList( type ) ||
isMap( type ) ||
TypeHelper.isArray( type );
}
/**
* Converts the given {@code Type} to a {@code Class}.
*
* @param type the type to convert
* @return the class corresponding to the type
*/
public static Class getClassFromType(Type type) {
if ( type instanceof Class ) {
return (Class) type;
}
if ( type instanceof ParameterizedType ) {
return getClassFromType( ( (ParameterizedType) type ).getRawType() );
}
if ( type instanceof GenericArrayType ) {
return Object[].class;
}
throw LOG.getUnableToConvertTypeToClassException( type );
}
/**
* @param type the type to check.
*
* @return Returns {@code true} if {@code type} is a iterable type, {@code false} otherwise.
*/
public static boolean isIterable(Type type) {
if ( type instanceof Class && Iterable.class.isAssignableFrom( (Class) type ) ) {
return true;
}
if ( type instanceof ParameterizedType ) {
return isIterable( ( (ParameterizedType) type ).getRawType() );
}
if ( type instanceof WildcardType ) {
Type[] upperBounds = ( (WildcardType) type ).getUpperBounds();
return upperBounds.length != 0 && isIterable( upperBounds[0] );
}
return false;
}
/**
* @param type the type to check.
*
* @return Returns {@code true} if {@code type} is implementing {@code Map}, {@code false} otherwise.
*/
public static boolean isMap(Type type) {
if ( type instanceof Class && Map.class.isAssignableFrom( (Class) type ) ) {
return true;
}
if ( type instanceof ParameterizedType ) {
return isMap( ( (ParameterizedType) type ).getRawType() );
}
if ( type instanceof WildcardType ) {
Type[] upperBounds = ( (WildcardType) type ).getUpperBounds();
return upperBounds.length != 0 && isMap( upperBounds[0] );
}
return false;
}
/**
* @param type the type to check.
*
* @return Returns {@code true} if {@code type} is implementing {@code List}, {@code false} otherwise.
*/
public static boolean isList(Type type) {
if ( type instanceof Class && List.class.isAssignableFrom( (Class) type ) ) {
return true;
}
if ( type instanceof ParameterizedType ) {
return isList( ( (ParameterizedType) type ).getRawType() );
}
if ( type instanceof WildcardType ) {
Type[] upperBounds = ( (WildcardType) type ).getUpperBounds();
return upperBounds.length != 0 && isList( upperBounds[0] );
}
return false;
}
/**
* Tries to retrieve the indexed value from the specified object.
*
* @param value The object from which to retrieve the indexed value. The object has to be non {@code null} and
* either a collection or array.
* @param index The index.
*
* @return The indexed value or {@code null} if {@code value} is {@code null} or not a collection or array.
* {@code null} is also returned in case the index does not exist.
*/
public static Object getIndexedValue(Object value, int index) {
if ( value == null ) {
return null;
}
Iterable iterable;
Type type = value.getClass();
if ( isIterable( type ) ) {
iterable = ( (Iterable) value );
}
else if ( TypeHelper.isArray( type ) ) {
iterable = CollectionHelper.iterableFromArray( value );
}
else {
return null;
}
int i = 0;
for ( Object o : iterable ) {
if ( i == index ) {
return o;
}
i++;
}
return null;
}
/**
* Tries to retrieve the mapped value from the specified object.
*
* @param value The object from which to retrieve the mapped value. The object has to be non {@code null} and
* must implement the @{code Map} interface.
* @param key The map key. index.
*
* @return The mapped value or {@code null} if {@code value} is {@code null} or not implementing @{code Map}.
*/
public static Object getMappedValue(Object value, Object key) {
if ( !( value instanceof Map ) ) {
return null;
}
Map map = (Map) value;
//noinspection SuspiciousMethodCalls
return map.get( key );
}
/**
* Returns the auto-boxed type of a primitive type.
*
* @param primitiveType the primitive type
*
* @return the auto-boxed type of a primitive type. In case {@link Void} is
* passed (which is considered as primitive type by
* {@link Class#isPrimitive()}), {@link Void} will be returned.
*
* @throws IllegalArgumentException in case the parameter {@code primitiveType} does not
* represent a primitive type.
*/
private static Class internalBoxedType(Class primitiveType) {
Class wrapperType = PRIMITIVE_TO_WRAPPER_TYPES.get( primitiveType );
if ( wrapperType == null ) {
throw LOG.getHasToBeAPrimitiveTypeException( primitiveType.getClass() );
}
return wrapperType;
}
/**
* Returns the corresponding auto-boxed type if given a primitive type. Returns the given type itself otherwise.
*/
public static Type boxedType(Type type) {
if ( type instanceof Class && ( (Class) type ).isPrimitive() ) {
return internalBoxedType( (Class) type );
}
else {
return type;
}
}
/**
* Returns the corresponding auto-boxed type if given a primitive type. Returns the given type itself otherwise.
*/
public static Class boxedType(Class type) {
if ( type.isPrimitive() ) {
return internalBoxedType( (Class) type );
}
else {
return type;
}
}
/**
* Returns the primitive type for a boxed type.
*
* @param type the boxed type
*
* @return the primitive type for a auto-boxed type. In case {@link Void} is
* passed (which is considered as primitive type by
* {@link Class#isPrimitive()}), {@link Void} will be returned.
*
* @throws IllegalArgumentException in case the parameter {@code primitiveType} does not
* represent a primitive type.
*/
public static Class unBoxedType(Class type) {
Class wrapperType = WRAPPER_TO_PRIMITIVE_TYPES.get( type );
if ( wrapperType == null ) {
throw LOG.getHasToBeABoxedTypeException( type.getClass() );
}
return wrapperType;
}
}