java/dagger/internal/codegen/langmodel/DaggerElements.java - platform/external/dagger2 - Git at Google

 /*
  * Copyright (C) 2013 The Dagger Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package dagger.internal.codegen.langmodel;

 import static androidx.room.compiler.processing.compat.XConverters.toJavac;
 import static com.google.auto.common.MoreElements.asExecutable;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.Lists.asList;
 import static dagger.internal.codegen.extension.DaggerStreams.toImmutableSet;
 import static java.util.Comparator.comparing;

 import androidx.room.compiler.processing.XMethodElement;
 import androidx.room.compiler.processing.XProcessingEnv;
 import androidx.room.compiler.processing.XTypeElement;
 import com.google.auto.common.MoreElements;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.squareup.javapoet.ClassName;
 import dagger.Reusable;
 import dagger.internal.codegen.base.ClearableCache;
 import java.io.Writer;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.AnnotationValue;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.Name;
 import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.QualifiedNameable;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.ArrayType;
 import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.ErrorType;
 import javax.lang.model.type.ExecutableType;
 import javax.lang.model.type.IntersectionType;
 import javax.lang.model.type.NoType;
 import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
 import javax.lang.model.type.WildcardType;
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.SimpleTypeVisitor8;
 import javax.lang.model.util.Types;

 /** Extension of {@link Elements} that adds Dagger-specific methods. */
 @Reusable
 public final class DaggerElements implements Elements, ClearableCache {
   private final Map<TypeElement, ImmutableSet<ExecutableElement>> getLocalAndInheritedMethodsCache =
       new HashMap<>();
   private final Elements elements;
   private final Types types;

   public DaggerElements(Elements elements, Types types) {
     this.elements = checkNotNull(elements);
     this.types = checkNotNull(types);
   }

   /**
    * Returns {@code true} if {@code encloser} is equal to or recursively encloses {@code enclosed}.
    */
   public static boolean transitivelyEncloses(Element encloser, Element enclosed) {
     Element current = enclosed;
     while (current != null) {
       if (current.equals(encloser)) {
         return true;
       }
       current = current.getEnclosingElement();
     }
     return false;
   }

   public ImmutableSet<ExecutableElement> getLocalAndInheritedMethods(TypeElement type) {
     return getLocalAndInheritedMethodsCache.computeIfAbsent(
         type, k -> MoreElements.getLocalAndInheritedMethods(type, types, elements));
   }

   @Override
   public TypeElement getTypeElement(CharSequence name) {
     return elements.getTypeElement(name);
   }

   /** Returns the type element for a class name. */
   public TypeElement getTypeElement(ClassName className) {
     return getTypeElement(className.canonicalName());
   }

   /** Returns the argument or the closest enclosing element that is a {@link TypeElement}. */
   public static TypeElement closestEnclosingTypeElement(Element element) {
     Element current = element;
     while (current != null) {
       if (MoreElements.isType(current)) {
         return MoreElements.asType(current);
       }
       current = current.getEnclosingElement();
     }
     throw new IllegalStateException("There is no enclosing TypeElement for: " + element);
   }

   /**
    * Compares elements according to their declaration order among siblings. Only valid to compare
    * elements enclosed by the same parent.
    */
   public static final Comparator<Element> DECLARATION_ORDER =
       comparing(element -> siblings(element).indexOf(element));

   // For parameter elements, element.getEnclosingElement().getEnclosedElements() is empty. So
   // instead look at the parameter list of the enclosing executable.
   private static List<? extends Element> siblings(Element element) {
     return element.getKind().equals(ElementKind.PARAMETER)
         ? asExecutable(element.getEnclosingElement()).getParameters()
         : element.getEnclosingElement().getEnclosedElements();
   }

   /**
    * Returns {@code true} iff the given element has an {@link AnnotationMirror} whose {@linkplain
    * AnnotationMirror#getAnnotationType() annotation type} has the same canonical name as any of
    * that of {@code annotationClasses}.
    */
   public static boolean isAnyAnnotationPresent(
       Element element, Iterable<ClassName> annotationClasses) {
     for (ClassName annotation : annotationClasses) {
       if (isAnnotationPresent(element, annotation)) {
         return true;
       }
     }
     return false;
   }

   @SafeVarargs
   public static boolean isAnyAnnotationPresent(
       Element element, ClassName first, ClassName... otherAnnotations) {
     return isAnyAnnotationPresent(element, asList(first, otherAnnotations));
   }

   /**
    * Returns {@code true} iff the given element has an {@link AnnotationMirror} whose {@link
    * AnnotationMirror#getAnnotationType() annotation type} has the same canonical name as that of
    * {@code annotationClass}. This method is a safer alternative to calling {@link
    * Element#getAnnotation} and checking for {@code null} as it avoids any interaction with
    * annotation proxies.
    */
   public static boolean isAnnotationPresent(Element element, ClassName annotationName) {
     return getAnnotationMirror(element, annotationName).isPresent();
   }

   // Note: This is similar to auto-common's MoreElements except using ClassName rather than Class.
   // TODO(bcorso): Contribute a String version to auto-common's MoreElements?
   /**
    * Returns an {@link AnnotationMirror} for the annotation of type {@code annotationClass} on
    * {@code element}, or {@link Optional#empty()} if no such annotation exists. This method is a
    * safer alternative to calling {@link Element#getAnnotation} as it avoids any interaction with
    * annotation proxies.
    */
   public static Optional<AnnotationMirror> getAnnotationMirror(
       Element element, ClassName annotationName) {
     String annotationClassName = annotationName.canonicalName();
     for (AnnotationMirror annotationMirror : element.getAnnotationMirrors()) {
       TypeElement annotationTypeElement =
           MoreElements.asType(annotationMirror.getAnnotationType().asElement());
       if (annotationTypeElement.getQualifiedName().contentEquals(annotationClassName)) {
         return Optional.of(annotationMirror);
       }
     }
     return Optional.empty();
   }

   public static ImmutableSet<? extends AnnotationMirror> getAnnotatedAnnotations(
       Element element, ClassName annotationName) {
     return element.getAnnotationMirrors().stream()
         .filter(input -> isAnnotationPresent(input.getAnnotationType().asElement(), annotationName))
         .collect(toImmutableSet());
   }

   /**
    * Returns the field descriptor of the given {@code element}.
    *
    * <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
    *
    * <p>For reference, see the <a
    * href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.2">JVM
    * specification, section 4.3.2</a>.
    */
   public static String getFieldDescriptor(VariableElement element) {
     return element.getSimpleName() + ":" + getDescriptor(element.asType());
   }

   /**
    * Returns the method descriptor of the given {@code element}.
    *
    * <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
    *
    * <p>For reference, see the <a
    * href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.3">JVM
    * specification, section 4.3.3</a>.
    */
   // TODO(bcorso): Expose getMethodDescriptor() method in XProcessing instead.
   public static String getMethodDescriptor(XMethodElement element) {
     return getMethodDescriptor(toJavac(element));
   }

   /**
    * Returns the method descriptor of the given {@code element}.
    *
    * <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
    *
    * <p>For reference, see the <a
    * href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.3">JVM
    * specification, section 4.3.3</a>.
    */
   public static String getMethodDescriptor(ExecutableElement element) {
     return element.getSimpleName() + getDescriptor(element.asType());
   }

   private static String getDescriptor(TypeMirror t) {
     return t.accept(JVM_DESCRIPTOR_TYPE_VISITOR, null);
   }

   private static final SimpleTypeVisitor8<String, Void> JVM_DESCRIPTOR_TYPE_VISITOR =
       new SimpleTypeVisitor8<String, Void>() {

         @Override
         public String visitArray(ArrayType arrayType, Void v) {
           return "[" + getDescriptor(arrayType.getComponentType());
         }

         @Override
         public String visitDeclared(DeclaredType declaredType, Void v) {
           return "L" + getInternalName(declaredType.asElement()) + ";";
         }

         @Override
         public String visitError(ErrorType errorType, Void v) {
           // For descriptor generating purposes we don't need a fully modeled type since we are
           // only interested in obtaining the class name in its "internal form".
           return visitDeclared(errorType, v);
         }

         @Override
         public String visitExecutable(ExecutableType executableType, Void v) {
           String parameterDescriptors =
               executableType.getParameterTypes().stream()
                   .map(DaggerElements::getDescriptor)
                   .collect(Collectors.joining());
           String returnDescriptor = getDescriptor(executableType.getReturnType());
           return "(" + parameterDescriptors + ")" + returnDescriptor;
         }

         @Override
         public String visitIntersection(IntersectionType intersectionType, Void v) {
           // For a type variable with multiple bounds: "the erasure of a type variable is determined
           // by the first type in its bound" - JVM Spec Sec 4.4
           return getDescriptor(intersectionType.getBounds().get(0));
         }

         @Override
         public String visitNoType(NoType noType, Void v) {
           return "V";
         }

         @Override
         public String visitPrimitive(PrimitiveType primitiveType, Void v) {
           switch (primitiveType.getKind()) {
             case BOOLEAN:
               return "Z";
             case BYTE:
               return "B";
             case SHORT:
               return "S";
             case INT:
               return "I";
             case LONG:
               return "J";
             case CHAR:
               return "C";
             case FLOAT:
               return "F";
             case DOUBLE:
               return "D";
             default:
               throw new IllegalArgumentException("Unknown primitive type.");
           }
         }

         @Override
         public String visitTypeVariable(TypeVariable typeVariable, Void v) {
           // The erasure of a type variable is the erasure of its leftmost bound. - JVM Spec Sec 4.6
           return getDescriptor(typeVariable.getUpperBound());
         }

         @Override
         public String defaultAction(TypeMirror typeMirror, Void v) {
           throw new IllegalArgumentException("Unsupported type: " + typeMirror);
         }

         @Override
         public String visitWildcard(WildcardType wildcardType, Void v) {
           return "";
         }

         /**
          * Returns the name of this element in its "internal form".
          *
          * <p>For reference, see the <a
          * href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.2">JVM
          * specification, section 4.2</a>.
          */
         private String getInternalName(Element element) {
           try {
             TypeElement typeElement = MoreElements.asType(element);
             switch (typeElement.getNestingKind()) {
               case TOP_LEVEL:
                 return typeElement.getQualifiedName().toString().replace('.', '/');
               case MEMBER:
                 return getInternalName(typeElement.getEnclosingElement())
                     + "$"
                     + typeElement.getSimpleName();
               default:
                 throw new IllegalArgumentException("Unsupported nesting kind.");
             }
           } catch (IllegalArgumentException e) {
             // Not a TypeElement, try something else...
           }

           if (element instanceof QualifiedNameable) {
             QualifiedNameable qualifiedNameElement = (QualifiedNameable) element;
             return qualifiedNameElement.getQualifiedName().toString().replace('.', '/');
           }

           return element.getSimpleName().toString();
         }
       };

   /** Returns the type element or throws {@link TypeNotPresentException} if it is null. */
   public static XTypeElement checkTypePresent(XProcessingEnv processingEnv, ClassName className) {
     return checkTypePresent(processingEnv, className.canonicalName());
   }

   /** Returns the type element or throws {@link TypeNotPresentException} if it is null. */
   public static XTypeElement checkTypePresent(XProcessingEnv processingEnv, String typeName) {
     XTypeElement type = processingEnv.findTypeElement(typeName);
     if (type == null) {
       throw new TypeNotPresentException(typeName, null);
     }
     return type;
   }

   @Override
   public PackageElement getPackageElement(CharSequence name) {
     return elements.getPackageElement(name);
   }

   @Override
   public Map<? extends ExecutableElement, ? extends AnnotationValue> getElementValuesWithDefaults(
       AnnotationMirror a) {
     return elements.getElementValuesWithDefaults(a);
   }

   /** Returns a map of annotation values keyed by attribute name. */
   public Map<String, ? extends AnnotationValue> getElementValuesWithDefaultsByName(
       AnnotationMirror a) {
     ImmutableMap.Builder<String, AnnotationValue> builder = ImmutableMap.builder();
     getElementValuesWithDefaults(a).forEach((k, v) -> builder.put(k.getSimpleName().toString(), v));
     return builder.build();
   }

   @Override
   public String getDocComment(Element e) {
     return elements.getDocComment(e);
   }

   @Override
   public boolean isDeprecated(Element e) {
     return elements.isDeprecated(e);
   }

   @Override
   public Name getBinaryName(TypeElement type) {
     return elements.getBinaryName(type);
   }

   @Override
   public PackageElement getPackageOf(Element type) {
     return elements.getPackageOf(type);
   }

   @Override
   public List<? extends Element> getAllMembers(TypeElement type) {
     return elements.getAllMembers(type);
   }

   @Override
   public List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e) {
     return elements.getAllAnnotationMirrors(e);
   }

   @Override
   public boolean hides(Element hider, Element hidden) {
     return elements.hides(hider, hidden);
   }

   @Override
   public boolean overrides(
       ExecutableElement overrider, ExecutableElement overridden, TypeElement type) {
     return elements.overrides(overrider, overridden, type);
   }

   @Override
   public String getConstantExpression(Object value) {
     return elements.getConstantExpression(value);
   }

   @Override
   public void printElements(Writer w, Element... elements) {
     this.elements.printElements(w, elements);
   }

   @Override
   public Name getName(CharSequence cs) { // SUPPRESS_GET_NAME_CHECK: This is not xprocessing usage.
     return elements.getName(cs); // SUPPRESS_GET_NAME_CHECK: This is not xprocessing usage.
   }

   @Override
   public boolean isFunctionalInterface(TypeElement type) {
     return elements.isFunctionalInterface(type);
   }

   @Override
   public void clearCache() {
     getLocalAndInheritedMethodsCache.clear();
   }
 }
	/*
	* Copyright (C) 2013 The Dagger Authors.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package dagger.internal.codegen.langmodel;

	import static androidx.room.compiler.processing.compat.XConverters.toJavac;
	import static com.google.auto.common.MoreElements.asExecutable;
	import static com.google.common.base.Preconditions.checkNotNull;
	import static com.google.common.collect.Lists.asList;
	import static dagger.internal.codegen.extension.DaggerStreams.toImmutableSet;
	import static java.util.Comparator.comparing;

	import androidx.room.compiler.processing.XMethodElement;
	import androidx.room.compiler.processing.XProcessingEnv;
	import androidx.room.compiler.processing.XTypeElement;
	import com.google.auto.common.MoreElements;
	import com.google.common.collect.ImmutableMap;
	import com.google.common.collect.ImmutableSet;
	import com.squareup.javapoet.ClassName;
	import dagger.Reusable;
	import dagger.internal.codegen.base.ClearableCache;
	import java.io.Writer;
	import java.util.Comparator;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Optional;
	import java.util.stream.Collectors;
	import javax.lang.model.element.AnnotationMirror;
	import javax.lang.model.element.AnnotationValue;
	import javax.lang.model.element.Element;
	import javax.lang.model.element.ElementKind;
	import javax.lang.model.element.ExecutableElement;
	import javax.lang.model.element.Name;
	import javax.lang.model.element.PackageElement;
	import javax.lang.model.element.QualifiedNameable;
	import javax.lang.model.element.TypeElement;
	import javax.lang.model.element.VariableElement;
	import javax.lang.model.type.ArrayType;
	import javax.lang.model.type.DeclaredType;
	import javax.lang.model.type.ErrorType;
	import javax.lang.model.type.ExecutableType;
	import javax.lang.model.type.IntersectionType;
	import javax.lang.model.type.NoType;
	import javax.lang.model.type.PrimitiveType;
	import javax.lang.model.type.TypeMirror;
	import javax.lang.model.type.TypeVariable;
	import javax.lang.model.type.WildcardType;
	import javax.lang.model.util.Elements;
	import javax.lang.model.util.SimpleTypeVisitor8;
	import javax.lang.model.util.Types;

	/** Extension of {@link Elements} that adds Dagger-specific methods. */
	@Reusable
	public final class DaggerElements implements Elements, ClearableCache {
	private final Map<TypeElement, ImmutableSet<ExecutableElement>> getLocalAndInheritedMethodsCache =
	new HashMap<>();
	private final Elements elements;
	private final Types types;

	public DaggerElements(Elements elements, Types types) {
	this.elements = checkNotNull(elements);
	this.types = checkNotNull(types);
	}

	/**
	* Returns {@code true} if {@code encloser} is equal to or recursively encloses {@code enclosed}.
	*/
	public static boolean transitivelyEncloses(Element encloser, Element enclosed) {
	Element current = enclosed;
	while (current != null) {
	if (current.equals(encloser)) {
	return true;
	}
	current = current.getEnclosingElement();
	}
	return false;
	}

	public ImmutableSet<ExecutableElement> getLocalAndInheritedMethods(TypeElement type) {
	return getLocalAndInheritedMethodsCache.computeIfAbsent(
	type, k -> MoreElements.getLocalAndInheritedMethods(type, types, elements));
	}

	@Override
	public TypeElement getTypeElement(CharSequence name) {
	return elements.getTypeElement(name);
	}

	/** Returns the type element for a class name. */
	public TypeElement getTypeElement(ClassName className) {
	return getTypeElement(className.canonicalName());
	}

	/** Returns the argument or the closest enclosing element that is a {@link TypeElement}. */
	public static TypeElement closestEnclosingTypeElement(Element element) {
	Element current = element;
	while (current != null) {
	if (MoreElements.isType(current)) {
	return MoreElements.asType(current);
	}
	current = current.getEnclosingElement();
	}
	throw new IllegalStateException("There is no enclosing TypeElement for: " + element);
	}

	/**
	* Compares elements according to their declaration order among siblings. Only valid to compare
	* elements enclosed by the same parent.
	*/
	public static final Comparator<Element> DECLARATION_ORDER =
	comparing(element -> siblings(element).indexOf(element));

	// For parameter elements, element.getEnclosingElement().getEnclosedElements() is empty. So
	// instead look at the parameter list of the enclosing executable.
	private static List<? extends Element> siblings(Element element) {
	return element.getKind().equals(ElementKind.PARAMETER)
	? asExecutable(element.getEnclosingElement()).getParameters()
	: element.getEnclosingElement().getEnclosedElements();
	}

	/**
	* Returns {@code true} iff the given element has an {@link AnnotationMirror} whose {@linkplain
	* AnnotationMirror#getAnnotationType() annotation type} has the same canonical name as any of
	* that of {@code annotationClasses}.
	*/
	public static boolean isAnyAnnotationPresent(
	Element element, Iterable<ClassName> annotationClasses) {
	for (ClassName annotation : annotationClasses) {
	if (isAnnotationPresent(element, annotation)) {
	return true;
	}
	}
	return false;
	}

	@SafeVarargs
	public static boolean isAnyAnnotationPresent(
	Element element, ClassName first, ClassName... otherAnnotations) {
	return isAnyAnnotationPresent(element, asList(first, otherAnnotations));
	}

	/**
	* Returns {@code true} iff the given element has an {@link AnnotationMirror} whose {@link
	* AnnotationMirror#getAnnotationType() annotation type} has the same canonical name as that of
	* {@code annotationClass}. This method is a safer alternative to calling {@link
	* Element#getAnnotation} and checking for {@code null} as it avoids any interaction with
	* annotation proxies.
	*/
	public static boolean isAnnotationPresent(Element element, ClassName annotationName) {
	return getAnnotationMirror(element, annotationName).isPresent();
	}

	// Note: This is similar to auto-common's MoreElements except using ClassName rather than Class.
	// TODO(bcorso): Contribute a String version to auto-common's MoreElements?
	/**
	* Returns an {@link AnnotationMirror} for the annotation of type {@code annotationClass} on
	* {@code element}, or {@link Optional#empty()} if no such annotation exists. This method is a
	* safer alternative to calling {@link Element#getAnnotation} as it avoids any interaction with
	* annotation proxies.
	*/
	public static Optional<AnnotationMirror> getAnnotationMirror(
	Element element, ClassName annotationName) {
	String annotationClassName = annotationName.canonicalName();
	for (AnnotationMirror annotationMirror : element.getAnnotationMirrors()) {
	TypeElement annotationTypeElement =
	MoreElements.asType(annotationMirror.getAnnotationType().asElement());
	if (annotationTypeElement.getQualifiedName().contentEquals(annotationClassName)) {
	return Optional.of(annotationMirror);
	}
	}
	return Optional.empty();
	}

	public static ImmutableSet<? extends AnnotationMirror> getAnnotatedAnnotations(
	Element element, ClassName annotationName) {
	return element.getAnnotationMirrors().stream()
	.filter(input -> isAnnotationPresent(input.getAnnotationType().asElement(), annotationName))
	.collect(toImmutableSet());
	}

	/**
	* Returns the field descriptor of the given {@code element}.
	*
	* <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
	*
	* <p>For reference, see the <a
	* href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.2">JVM
	* specification, section 4.3.2</a>.
	*/
	public static String getFieldDescriptor(VariableElement element) {
	return element.getSimpleName() + ":" + getDescriptor(element.asType());
	}

	/**
	* Returns the method descriptor of the given {@code element}.
	*
	* <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
	*
	* <p>For reference, see the <a
	* href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.3">JVM
	* specification, section 4.3.3</a>.
	*/
	// TODO(bcorso): Expose getMethodDescriptor() method in XProcessing instead.
	public static String getMethodDescriptor(XMethodElement element) {
	return getMethodDescriptor(toJavac(element));
	}

	/**
	* Returns the method descriptor of the given {@code element}.
	*
	* <p>This is useful for matching Kotlin Metadata JVM Signatures with elements from the AST.
	*
	* <p>For reference, see the <a
	* href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.3">JVM
	* specification, section 4.3.3</a>.
	*/
	public static String getMethodDescriptor(ExecutableElement element) {
	return element.getSimpleName() + getDescriptor(element.asType());
	}

	private static String getDescriptor(TypeMirror t) {
	return t.accept(JVM_DESCRIPTOR_TYPE_VISITOR, null);
	}

	private static final SimpleTypeVisitor8<String, Void> JVM_DESCRIPTOR_TYPE_VISITOR =
	new SimpleTypeVisitor8<String, Void>() {

	@Override
	public String visitArray(ArrayType arrayType, Void v) {
	return "[" + getDescriptor(arrayType.getComponentType());
	}

	@Override
	public String visitDeclared(DeclaredType declaredType, Void v) {
	return "L" + getInternalName(declaredType.asElement()) + ";";
	}

	@Override
	public String visitError(ErrorType errorType, Void v) {
	// For descriptor generating purposes we don't need a fully modeled type since we are
	// only interested in obtaining the class name in its "internal form".
	return visitDeclared(errorType, v);
	}

	@Override
	public String visitExecutable(ExecutableType executableType, Void v) {
	String parameterDescriptors =
	executableType.getParameterTypes().stream()
	.map(DaggerElements::getDescriptor)
	.collect(Collectors.joining());
	String returnDescriptor = getDescriptor(executableType.getReturnType());
	return "(" + parameterDescriptors + ")" + returnDescriptor;
	}

	@Override
	public String visitIntersection(IntersectionType intersectionType, Void v) {
	// For a type variable with multiple bounds: "the erasure of a type variable is determined
	// by the first type in its bound" - JVM Spec Sec 4.4
	return getDescriptor(intersectionType.getBounds().get(0));
	}

	@Override
	public String visitNoType(NoType noType, Void v) {
	return "V";
	}

	@Override
	public String visitPrimitive(PrimitiveType primitiveType, Void v) {
	switch (primitiveType.getKind()) {
	case BOOLEAN:
	return "Z";
	case BYTE:
	return "B";
	case SHORT:
	return "S";
	case INT:
	return "I";
	case LONG:
	return "J";
	case CHAR:
	return "C";
	case FLOAT:
	return "F";
	case DOUBLE:
	return "D";
	default:
	throw new IllegalArgumentException("Unknown primitive type.");
	}
	}

	@Override
	public String visitTypeVariable(TypeVariable typeVariable, Void v) {
	// The erasure of a type variable is the erasure of its leftmost bound. - JVM Spec Sec 4.6
	return getDescriptor(typeVariable.getUpperBound());
	}

	@Override
	public String defaultAction(TypeMirror typeMirror, Void v) {
	throw new IllegalArgumentException("Unsupported type: " + typeMirror);
	}

	@Override
	public String visitWildcard(WildcardType wildcardType, Void v) {
	return "";
	}

	/**
	* Returns the name of this element in its "internal form".
	*
	* <p>For reference, see the <a
	* href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.2">JVM
	* specification, section 4.2</a>.
	*/
	private String getInternalName(Element element) {
	try {
	TypeElement typeElement = MoreElements.asType(element);
	switch (typeElement.getNestingKind()) {
	case TOP_LEVEL:
	return typeElement.getQualifiedName().toString().replace('.', '/');
	case MEMBER:
	return getInternalName(typeElement.getEnclosingElement())
	+ "$"
	+ typeElement.getSimpleName();
	default:
	throw new IllegalArgumentException("Unsupported nesting kind.");
	}
	} catch (IllegalArgumentException e) {
	// Not a TypeElement, try something else...
	}

	if (element instanceof QualifiedNameable) {
	QualifiedNameable qualifiedNameElement = (QualifiedNameable) element;
	return qualifiedNameElement.getQualifiedName().toString().replace('.', '/');
	}

	return element.getSimpleName().toString();
	}
	};

	/** Returns the type element or throws {@link TypeNotPresentException} if it is null. */
	public static XTypeElement checkTypePresent(XProcessingEnv processingEnv, ClassName className) {
	return checkTypePresent(processingEnv, className.canonicalName());
	}

	/** Returns the type element or throws {@link TypeNotPresentException} if it is null. */
	public static XTypeElement checkTypePresent(XProcessingEnv processingEnv, String typeName) {
	XTypeElement type = processingEnv.findTypeElement(typeName);
	if (type == null) {
	throw new TypeNotPresentException(typeName, null);
	}
	return type;
	}

	@Override
	public PackageElement getPackageElement(CharSequence name) {
	return elements.getPackageElement(name);
	}

	@Override
	public Map<? extends ExecutableElement, ? extends AnnotationValue> getElementValuesWithDefaults(
	AnnotationMirror a) {
	return elements.getElementValuesWithDefaults(a);
	}

	/** Returns a map of annotation values keyed by attribute name. */
	public Map<String, ? extends AnnotationValue> getElementValuesWithDefaultsByName(
	AnnotationMirror a) {
	ImmutableMap.Builder<String, AnnotationValue> builder = ImmutableMap.builder();
	getElementValuesWithDefaults(a).forEach((k, v) -> builder.put(k.getSimpleName().toString(), v));
	return builder.build();
	}

	@Override
	public String getDocComment(Element e) {
	return elements.getDocComment(e);
	}

	@Override
	public boolean isDeprecated(Element e) {
	return elements.isDeprecated(e);
	}

	@Override
	public Name getBinaryName(TypeElement type) {
	return elements.getBinaryName(type);
	}

	@Override
	public PackageElement getPackageOf(Element type) {
	return elements.getPackageOf(type);
	}

	@Override
	public List<? extends Element> getAllMembers(TypeElement type) {
	return elements.getAllMembers(type);
	}

	@Override
	public List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e) {
	return elements.getAllAnnotationMirrors(e);
	}

	@Override
	public boolean hides(Element hider, Element hidden) {
	return elements.hides(hider, hidden);
	}

	@Override
	public boolean overrides(
	ExecutableElement overrider, ExecutableElement overridden, TypeElement type) {
	return elements.overrides(overrider, overridden, type);
	}

	@Override
	public String getConstantExpression(Object value) {
	return elements.getConstantExpression(value);
	}

	@Override
	public void printElements(Writer w, Element... elements) {
	this.elements.printElements(w, elements);
	}

	@Override
	public Name getName(CharSequence cs) { // SUPPRESS_GET_NAME_CHECK: This is not xprocessing usage.
	return elements.getName(cs); // SUPPRESS_GET_NAME_CHECK: This is not xprocessing usage.
	}

	@Override
	public boolean isFunctionalInterface(TypeElement type) {
	return elements.isFunctionalInterface(type);
	}

	@Override
	public void clearCache() {
	getLocalAndInheritedMethodsCache.clear();
	}
	}