Class Reflections

java.lang.Object
org.reflections.Reflections

public class Reflections extends Object
Reflections one-stop-shop object

Reflections scans your classpath, indexes the metadata, allows you to query it on runtime and may save and collect that information for many modules within your project.

Using Reflections you can query your metadata such as:

  • get all subtypes of some type
  • get all types/constructors/methods/fields annotated with some annotation, optionally with annotation parameters matching
  • get all resources matching matching a regular expression
  • get all methods with specific signature including parameters, parameter annotations and return type
  • get all methods parameter names
  • get all fields/methods/constructors usages in code

A typical use of Reflections would be:

      Reflections reflections = new Reflections("my.project.prefix");

      Set&#60Class&#60? extends SomeType>> subTypes = reflections.getSubTypesOf(SomeType.class);

      Set&#60Class&#60?>> annotated = reflections.getTypesAnnotatedWith(SomeAnnotation.class);
 

Basically, to use Reflections first instantiate it with one of the constructors, then depending on the scanners, use the convenient query methods:

      Reflections reflections = new Reflections("my.package.prefix");
      //or
      Reflections reflections = new Reflections(ClasspathHelper.forPackage("my.package.prefix"),
            new SubTypesScanner(), new TypesAnnotationScanner(), new FilterBuilder().include(...), ...);

       //or using the ConfigurationBuilder
       new Reflections(new ConfigurationBuilder()
            .filterInputsBy(new FilterBuilder().include(FilterBuilder.prefix("my.project.prefix")))
            .setUrls(ClasspathHelper.forPackage("my.project.prefix"))
            .setScanners(new SubTypesScanner(), new TypeAnnotationsScanner().filterResultsBy(optionalFilter), ...));
 
And then query, for example:
       Set&#60Class&#60? extends Module>> modules = reflections.getSubTypesOf(com.google.inject.Module.class);
       Set&#60Class&#60?>> singletons =             reflections.getTypesAnnotatedWith(javax.inject.Singleton.class);

       Set&#60String> properties =       reflections.getResources(Pattern.compile(".*\\.properties"));
       Set&#60Constructor> injectables = reflections.getConstructorsAnnotatedWith(javax.inject.Inject.class);
       Set&#60Method> deprecateds =      reflections.getMethodsAnnotatedWith(javax.ws.rs.Path.class);
       Set&#60Field> ids =               reflections.getFieldsAnnotatedWith(javax.persistence.Id.class);

       Set&#60Method> someMethods =      reflections.getMethodsMatchParams(long.class, int.class);
       Set&#60Method> voidMethods =      reflections.getMethodsReturn(void.class);
       Set&#60Method> pathParamMethods = reflections.getMethodsWithAnyParamAnnotated(PathParam.class);
       Set&#60Method> floatToString =    reflections.getConverters(Float.class, String.class);
       List&#60String> parameterNames =  reflections.getMethodsParamNames(Method.class);

       Set&#60Member> fieldUsage =       reflections.getFieldUsage(Field.class);
       Set&#60Member> methodUsage =      reflections.getMethodUsage(Method.class);
       Set&#60Member> constructorUsage = reflections.getConstructorUsage(Constructor.class);
 

You can use other scanners defined in Reflections as well, such as: SubTypesScanner, TypeAnnotationsScanner (both default), ResourcesScanner, MethodAnnotationsScanner, ConstructorAnnotationsScanner, FieldAnnotationsScanner, MethodParameterScanner, MethodParameterNamesScanner, MemberUsageScanner or any custom scanner.

Use getStore() to access and query the store directly

In order to save the store metadata, use save(String) or save(String, org.reflections.serializers.Serializer) for example with XmlSerializer or JavaCodeSerializer

In order to collect pre saved metadata and avoid re-scanning, use collect(String, java.util.function.Predicate, org.reflections.serializers.Serializer...)}

Make sure to scan all the transitively relevant packages.
for instance, given your class C extends B extends A, and both B and A are located in another package than C, when only the package of C is scanned - then querying for sub types of A returns nothing (transitive), but querying for sub types of B returns C (direct). In that case make sure to scan all relevant packages a priori.

For Javadoc, source code, and more information about Reflections Library, see http://github.com/ronmamo/reflections/

  • Field Details

    • log

      public static org.slf4j.Logger log
    • configuration

      protected final transient Configuration configuration
    • store

      protected Store store
  • Constructor Details

  • Method Details

    • scan

      protected void scan()
    • producingDescription

      private static String producingDescription(Store store)
    • scan

      protected void scan(URL url)
    • collect

      public static Reflections collect()
      collect saved Reflection xml resources and merge it into a Reflections instance

      by default, resources are collected from all urls that contains the package META-INF/reflections and includes files matching the pattern .*-reflections.xml

    • collect

      public static Reflections collect(String packagePrefix, Predicate<String> resourceNameFilter, Serializer... optionalSerializer)
      collect saved Reflections resources from all urls that contains the given packagePrefix and matches the given resourceNameFilter and de-serializes them using the default serializer XmlSerializer or using the optionally supplied optionalSerializer

      it is preferred to use a designated resource prefix (for example META-INF/reflections but not just META-INF), so that relevant urls could be found much faster

      Parameters:
      optionalSerializer - - optionally supply one serializer instance. if not specified or null, XmlSerializer will be used
    • collect

      public Reflections collect(InputStream inputStream)
      merges saved Reflections resources from the given input stream, using the serializer configured in this instance's Configuration
      useful if you know the serialized resource location and prefer not to look it up the classpath
    • collect

      public Reflections collect(File file)
      merges saved Reflections resources from the given file, using the serializer configured in this instance's Configuration

      useful if you know the serialized resource location and prefer not to look it up the classpath

    • merge

      public Reflections merge(Reflections reflections)
      merges a Reflections instance metadata into this instance
    • expandSuperTypes

      public void expandSuperTypes()
      expand super types after scanning, for super types that were not scanned. this is helpful in finding the transitive closure without scanning all 3rd party dependencies. it uses ReflectionUtils.getSuperTypes(Class).

      for example, for classes A,B,C where A supertype of B, B supertype of C:

      • if scanning C resulted in B (B->C in store), but A was not scanned (although A supertype of B) - then getSubTypes(A) will not return C
      • if expanding supertypes, B will be expanded with A (A->B in store) - then getSubTypes(A) will return C
    • expandSupertypes

      private void expandSupertypes(Store store, String key, Class<?> type)
    • getSubTypesOf

      public <T> Set<Class<? extends T>> getSubTypesOf(Class<T> type)
      gets all sub types in hierarchy of a given type

      depends on SubTypesScanner configured

    • getTypesAnnotatedWith

      public Set<Class<?>> getTypesAnnotatedWith(Class<? extends Annotation> annotation)
      get types annotated with a given annotation, both classes and annotations

      Inherited is not honored by default.

      when honoring @Inherited, meta-annotation should only effect annotated super classes and its sub types

      Note that this (@Inherited) meta-annotation type has no effect if the annotated type is used for anything other then a class. Also, this meta-annotation causes annotations to be inherited only from superclasses; annotations on implemented interfaces have no effect.

      depends on TypeAnnotationsScanner and SubTypesScanner configured

    • getTypesAnnotatedWith

      public Set<Class<?>> getTypesAnnotatedWith(Class<? extends Annotation> annotation, boolean honorInherited)
      get types annotated with a given annotation, both classes and annotations

      Inherited is honored according to given honorInherited.

      when honoring @Inherited, meta-annotation should only effect annotated super classes and it's sub types

      when not honoring @Inherited, meta annotation effects all subtypes, including annotations interfaces and classes

      Note that this (@Inherited) meta-annotation type has no effect if the annotated type is used for anything other then a class. Also, this meta-annotation causes annotations to be inherited only from superclasses; annotations on implemented interfaces have no effect.

      depends on TypeAnnotationsScanner and SubTypesScanner configured

    • getTypesAnnotatedWith

      public Set<Class<?>> getTypesAnnotatedWith(Annotation annotation)
      get types annotated with a given annotation, both classes and annotations, including annotation member values matching

      Inherited is not honored by default

      depends on TypeAnnotationsScanner configured

    • getTypesAnnotatedWith

      public Set<Class<?>> getTypesAnnotatedWith(Annotation annotation, boolean honorInherited)
      get types annotated with a given annotation, both classes and annotations, including annotation member values matching

      Inherited is honored according to given honorInherited

      depends on TypeAnnotationsScanner configured

    • getAllAnnotated

      protected Collection<String> getAllAnnotated(Collection<String> annotated, Class<? extends Annotation> annotation, boolean honorInherited)
    • getMethodsAnnotatedWith

      public Set<Method> getMethodsAnnotatedWith(Class<? extends Annotation> annotation)
      get all methods annotated with a given annotation

      depends on MethodAnnotationsScanner configured

    • getMethodsAnnotatedWith

      public Set<Method> getMethodsAnnotatedWith(Annotation annotation)
      get all methods annotated with a given annotation, including annotation member values matching

      depends on MethodAnnotationsScanner configured

    • getMethodsMatchParams

      public Set<Method> getMethodsMatchParams(Class<?>... types)
      get methods with parameter types matching given types
    • getMethodsReturn

      public Set<Method> getMethodsReturn(Class returnType)
      get methods with return type match given type
    • getMethodsWithAnyParamAnnotated

      public Set<Method> getMethodsWithAnyParamAnnotated(Class<? extends Annotation> annotation)
      get methods with any parameter annotated with given annotation
    • getMethodsWithAnyParamAnnotated

      public Set<Method> getMethodsWithAnyParamAnnotated(Annotation annotation)
      get methods with any parameter annotated with given annotation, including annotation member values matching
    • getConstructorsAnnotatedWith

      public Set<Constructor> getConstructorsAnnotatedWith(Class<? extends Annotation> annotation)
      get all constructors annotated with a given annotation

      depends on MethodAnnotationsScanner configured

    • getConstructorsAnnotatedWith

      public Set<Constructor> getConstructorsAnnotatedWith(Annotation annotation)
      get all constructors annotated with a given annotation, including annotation member values matching

      depends on MethodAnnotationsScanner configured

    • getConstructorsMatchParams

      public Set<Constructor> getConstructorsMatchParams(Class<?>... types)
      get constructors with parameter types matching given types
    • getConstructorsWithAnyParamAnnotated

      public Set<Constructor> getConstructorsWithAnyParamAnnotated(Class<? extends Annotation> annotation)
      get constructors with any parameter annotated with given annotation
    • getConstructorsWithAnyParamAnnotated

      public Set<Constructor> getConstructorsWithAnyParamAnnotated(Annotation annotation)
      get constructors with any parameter annotated with given annotation, including annotation member values matching
    • getFieldsAnnotatedWith

      public Set<Field> getFieldsAnnotatedWith(Class<? extends Annotation> annotation)
      get all fields annotated with a given annotation

      depends on FieldAnnotationsScanner configured

    • getFieldsAnnotatedWith

      public Set<Field> getFieldsAnnotatedWith(Annotation annotation)
      get all methods annotated with a given annotation, including annotation member values matching

      depends on FieldAnnotationsScanner configured

    • getResources

      public Set<String> getResources(Predicate<String> namePredicate)
      get resources relative paths where simple name (key) matches given namePredicate

      depends on ResourcesScanner configured

    • getResources

      public Set<String> getResources(Pattern pattern)
      get resources relative paths where simple name (key) matches given regular expression

      depends on ResourcesScanner configured

      Set xmls = reflections.getResources(".*\\.xml");
    • getMethodParamNames

      public List<String> getMethodParamNames(Method method)
      get parameter names of given method

      depends on MethodParameterNamesScanner configured

    • getConstructorParamNames

      public List<String> getConstructorParamNames(Constructor constructor)
      get parameter names of given constructor

      depends on MethodParameterNamesScanner configured

    • getFieldUsage

      public Set<Member> getFieldUsage(Field field)
      get all given field usages in methods and constructors

      depends on MemberUsageScanner configured

    • getMethodUsage

      public Set<Member> getMethodUsage(Method method)
      get all given method usages in methods and constructors

      depends on MemberUsageScanner configured

    • getConstructorUsage

      public Set<Member> getConstructorUsage(Constructor constructor)
      get all given constructors usages in methods and constructors

      depends on MemberUsageScanner configured

    • getAllTypes

      public Set<String> getAllTypes()
      get all types scanned. this is effectively similar to getting all subtypes of Object.

      depends on SubTypesScanner configured with SubTypesScanner(false), otherwise ReflectionsException is thrown

      note using this might be a bad practice. it is better to get types matching some criteria, such as getSubTypesOf(Class) or getTypesAnnotatedWith(Class)

      Returns:
      Set of String, and not of Class, in order to avoid definition of all types in PermGen
    • getStore

      public Store getStore()
      returns the Store used for storing and querying the metadata
    • getConfiguration

      public Configuration getConfiguration()
      returns the Configuration object of this instance
    • save

      public File save(String filename)
      serialize to a given directory and filename

      * it is preferred to specify a designated directory (for example META-INF/reflections), so that it could be found later much faster using the load method

      see the documentation for the save method on the configured Serializer

    • save

      public File save(String filename, Serializer serializer)
      serialize to a given directory and filename using given serializer

      * it is preferred to specify a designated directory (for example META-INF/reflections), so that it could be found later much faster using the load method

    • loaders

      private ClassLoader[] loaders()