com.google.auto.common

Class MoreElements

java.lang.Object

com.google.auto.common.MoreElements

@Beta
public final class MoreElements
extends java.lang.Object

Static utility methods pertaining to Element instances.

Author:

Gregory Kick

Method Summary

Modifier and Type	Method and Description
static javax.lang.model.element.ExecutableElement	asExecutable(javax.lang.model.element.Element element) Returns the given Element instance as ExecutableElement.
static javax.lang.model.element.PackageElement	asPackage(javax.lang.model.element.Element element) Returns the given Element instance as PackageElement.
static javax.lang.model.element.TypeElement	asType(javax.lang.model.element.Element element) Returns the given Element instance as TypeElement.
static javax.lang.model.element.VariableElement	asVariable(javax.lang.model.element.Element element) Returns the given Element instance as VariableElement.
static com.google.common.base.Optional<javax.lang.model.element.AnnotationMirror>	getAnnotationMirror(javax.lang.model.element.Element element, java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass) Returns an AnnotationMirror for the annotation of type annotationClass on element, or Optional.absent() if no such annotation exists.
static com.google.common.collect.ImmutableSet<javax.lang.model.element.ExecutableElement>	getLocalAndInheritedMethods(javax.lang.model.element.TypeElement type, javax.lang.model.util.Elements elementUtils) Deprecated. The method getLocalAndInheritedMethods(TypeElement, Types, Elements) has better consistency between Java compilers.
static com.google.common.collect.ImmutableSet<javax.lang.model.element.ExecutableElement>	getLocalAndInheritedMethods(javax.lang.model.element.TypeElement type, javax.lang.model.util.Types typeUtils, javax.lang.model.util.Elements elementUtils) Returns the set of all non-private methods from type, including methods that it inherits from its ancestors.
static javax.lang.model.element.PackageElement	getPackage(javax.lang.model.element.Element element) An alternate implementation of Elements.getPackageOf(javax.lang.model.element.Element) that does not require an Elements instance.
static <T extends javax.lang.model.element.Element> com.google.common.base.Predicate<T>	hasModifiers(javax.lang.model.element.Modifier... modifiers) Returns a Predicate that can be used to filter elements by Modifier.
static <T extends javax.lang.model.element.Element> com.google.common.base.Predicate<T>	hasModifiers(java.util.Set<javax.lang.model.element.Modifier> modifiers) Returns a Predicate that can be used to filter elements by Modifier.
static boolean	isAnnotationPresent(javax.lang.model.element.Element element, java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass) Returns true iff the given element has an AnnotationMirror whose annotation type has the same canonical name as that of annotationClass.
static boolean	isType(javax.lang.model.element.Element element) Returns true if the given Element instance is a TypeElement.

Methods inherited from class java.lang.Object

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

Method Detail

getPackage

public static javax.lang.model.element.PackageElement getPackage(javax.lang.model.element.Element element)

An alternate implementation of Elements.getPackageOf(javax.lang.model.element.Element) that does not require an Elements instance.

Throws:

java.lang.NullPointerException - if element is null

asPackage

public static javax.lang.model.element.PackageElement asPackage(javax.lang.model.element.Element element)

Returns the given Element instance as PackageElement.

This method is functionally equivalent to an instanceof check and a cast, but should always be used over that idiom as instructed in the documentation for Element.

Throws:

java.lang.NullPointerException - if element is null

java.lang.IllegalArgumentException - if element isn't a PackageElement.

isType

public static boolean isType(javax.lang.model.element.Element element)

Returns true if the given Element instance is a TypeElement.

This method is functionally equivalent to an instanceof check, but should always be used over that idiom as instructed in the documentation for Element.

Throws:

java.lang.NullPointerException - if element is null

asType

public static javax.lang.model.element.TypeElement asType(javax.lang.model.element.Element element)

Returns the given Element instance as TypeElement.

This method is functionally equivalent to an instanceof check and a cast, but should always be used over that idiom as instructed in the documentation for Element.

Throws:

java.lang.NullPointerException - if element is null

java.lang.IllegalArgumentException - if element isn't a TypeElement.

asVariable

public static javax.lang.model.element.VariableElement asVariable(javax.lang.model.element.Element element)

Returns the given Element instance as VariableElement.

This method is functionally equivalent to an instanceof check and a cast, but should always be used over that idiom as instructed in the documentation for Element.

Throws:

java.lang.NullPointerException - if element is null

java.lang.IllegalArgumentException - if element isn't a VariableElement.

asExecutable

public static javax.lang.model.element.ExecutableElement asExecutable(javax.lang.model.element.Element element)

Returns the given Element instance as ExecutableElement.

This method is functionally equivalent to an instanceof check and a cast, but should always be used over that idiom as instructed in the documentation for Element.

Throws:

java.lang.NullPointerException - if element is null

java.lang.IllegalArgumentException - if element isn't a ExecutableElement.

isAnnotationPresent

public static boolean isAnnotationPresent(javax.lang.model.element.Element element,
                                          java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass)

Returns true iff the given element has an AnnotationMirror whose annotation type has the same canonical name as that of annotationClass. This method is a safer alternative to calling Element.getAnnotation(java.lang.Class<A>) and checking for null as it avoids any interaction with . This() { super(); } . This() { super(); } annotation proxies.

getAnnotationMirror

public static com.google.common.base.Optional<javax.lang.model.element.AnnotationMirror> getAnnotationMirror(javax.lang.model.element.Element element,
                                                                                                             java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass)

Returns an AnnotationMirror for the annotation of type annotationClass on element, or Optional.absent() if no such annotation exists. This method is a safer alternative to calling Element.getAnnotation(java.lang.Class<A>) as it avoids any interaction with annotation proxies.

hasModifiers

public static <T extends javax.lang.model.element.Element> com.google.common.base.Predicate<T> hasModifiers(javax.lang.model.element.Modifier... modifiers)

Returns a Predicate that can be used to filter elements by Modifier. The predicate returns true if the input Element has all of the given modifiers, perhaps in addition to others.

Here is an example how one could get a List of static methods of a class:

 FluentIterable.from(ElementFilter.methodsIn(clazzElement.getEnclosedElements()))
     .filter(MoreElements.hasModifiers(Modifier.STATIC).toList();
 

hasModifiers

public static <T extends javax.lang.model.element.Element> com.google.common.base.Predicate<T> hasModifiers(java.util.Set<javax.lang.model.element.Modifier> modifiers)

Returns a Predicate that can be used to filter elements by Modifier. The predicate returns true if the input Element has all of the given modifiers, perhaps in addition to others.

Here is an example how one could get a List of methods with certain modifiers of a class:

 Set<Modifier> modifiers = ...;
 FluentIterable.from(ElementFilter.methodsIn(clazzElement.getEnclosedElements()))
     .filter(MoreElements.hasModifiers(modifiers).toList();
 

getLocalAndInheritedMethods

@Deprecated
public static com.google.common.collect.ImmutableSet<javax.lang.model.element.ExecutableElement> getLocalAndInheritedMethods(javax.lang.model.element.TypeElement type,
                                                                                                                                         javax.lang.model.util.Elements elementUtils)

Deprecated. The method getLocalAndInheritedMethods(TypeElement, Types, Elements) has better consistency between Java compilers.

Returns the set of all non-private methods from type, including methods that it inherits from its ancestors. Inherited methods that are overridden are not included in the result. So if type defines public String toString(), the returned set will contain that method, but not the toString() method defined by Object.

The returned set may contain more than one method with the same signature, if type inherits those methods from different ancestors. For example, if it inherits from unrelated interfaces One and Two which each define void foo();, and if it does not itself override the foo() method, then both One.foo() and Two.foo() will be in the returned set.

Parameters:

type - the type whose own and inherited methods are to be returned

elementUtils - an Elements object, typically returned by processingEnv.getElementUtils()

getLocalAndInheritedMethods

public static com.google.common.collect.ImmutableSet<javax.lang.model.element.ExecutableElement> getLocalAndInheritedMethods(javax.lang.model.element.TypeElement type,
                                                                                                                             javax.lang.model.util.Types typeUtils,
                                                                                                                             javax.lang.model.util.Elements elementUtils)

Returns the set of all non-private methods from type, including methods that it inherits from its ancestors. Inherited methods that are overridden are not included in the result. So if type defines public String toString(), the returned set will contain that method, but not the toString() method defined by Object.

The returned set may contain more than one method with the same signature, if type inherits those methods from different ancestors. For example, if it inherits from unrelated interfaces One and Two which each define void foo();, and if it does not itself override the foo() method, then both One.foo() and Two.foo() will be in the returned set.

Parameters:

type - the type whose own and inherited methods are to be returned

typeUtils - a Types object, typically returned by processingEnv.getTypeUtils()

elementUtils - an Elements object, typically returned by processingEnv.getElementUtils()