Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2019 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation * Stephan Herrmann - Contribution for * Bug 429813 - [1.8][dom ast] IMethodBinding#getJavaElement() should return IMethod for lambda *******************************************************************************/ package org.eclipse.jdt.core.dom; /** * A method binding represents a method or constructor of a class or interface. * Method bindings usually correspond directly to method or * constructor declarations found in the source code. * However, in certain cases of references to a generic method, * the method binding may correspond to a copy of a generic method * declaration with substitutions for the method's type parameters * (for these, <code>getTypeArguments</code> returns a non-empty * list, and either <code>isParameterizedMethod</code> or * <code>isRawMethod</code> returns <code>true</code>). * And in certain cases of references to a method declared in a * generic type, the method binding may correspond to a copy of a * method declaration with substitutions for the type's type * parameters (for these, <code>getTypeArguments</code> returns * an empty list, and both <code>isParameterizedMethod</code> and * <code>isRawMethod</code> return <code>false</code>). * * @see ITypeBinding#getDeclaredMethods() * @since 2.0 * @noimplement This interface is not intended to be implemented by clients. */ public interface IMethodBinding extends IBinding { /** * Returns whether this binding is for a constructor or a method. * * @return <code>true</code> if this is the binding for a constructor, * and <code>false</code> if this is the binding for a method */ public boolean isConstructor(); /** * Returns whether this binding is known to be a compiler-generated * default constructor. * <p> * This method returns <code>false</code> for: * <ul> * <li>methods</li> * <li>constructors with more than one parameter</li> * <li>0-argument constructors where the binding information was obtained * from a Java source file containing an explicit 0-argument constructor * declaration</li> * <li>0-argument constructors where the binding information was obtained * from a Java class file (it is not possible to determine from a * class file whether a 0-argument constructor was present in the source * code versus generated automatically by a Java compiler)</li> * </ul> * * @return <code>true</code> if this is known to be the binding for a * compiler-generated default constructor, and <code>false</code> * otherwise * @since 3.0 */ public boolean isDefaultConstructor(); /** * Returns the name of the method declared in this binding. The method name * is always a simple identifier. The name of a constructor is always the * same as the declared name of its declaring class. * * @return the name of this method, or the declared name of this * constructor's declaring class */ @Override public String getName(); /** * Returns the type binding representing the class or interface * that declares this method or constructor. * * @return the binding of the class or interface that declares this method * or constructor */ public ITypeBinding getDeclaringClass(); /** * If this method binding represents a lambda expression then: * <ul> * <li>If the lambda expression is declared in the body of a method, * answers the binding of that declaring method. * </li> * <li>Otherwise, if the lambda expression is declared in the * initializer of a field, answers the binding of that declaring field. * </li> * <li>Otherwise, if the lambda expression is declared in a static initializer or an * instance initializer, a method binding is returned to represent that initializer * (selector is an empty string in this case). * </li> * </ul> * <p> * If this method binding does not represent a lambda expression, * <code>null</code> is returned. * </p> * @return a method binding or field binding representing the member that * contains the lambda expression represented by this method binding, * or null for regular method bindings. * @since 3.11 */ public IBinding getDeclaringMember(); /** * Returns the resolved default value of an annotation type member, * or <code>null</code> if the member has no default value, or if this * is not the binding for an annotation type member. * <p> * Resolved values are represented as follows (same as for * {@link IMemberValuePairBinding#getValue()}): * <ul> * <li>Primitive type - the equivalent boxed object</li> * <li>java.lang.Class - the <code>ITypeBinding</code> for the class object</li> * <li>java.lang.String - the string value itself</li> * <li>enum type - the <code>IVariableBinding</code> for the enum constant</li> * <li>annotation type - an <code>IAnnotationBinding</code></li> * <li>array type - an <code>Object[]</code> whose elements are as per above * (the language only allows single dimensional arrays in annotations)</li> * </ul> * * @return the default value of this annotation type member, or <code>null</code> * if none or not applicable * @since 3.2 */ public Object getDefaultValue(); /** * Returns the resolved declaration annotations of a parameter of this method. * The result returned is the same regardless of whether * this is a parameterized method. * <p> * <b>Note:</b> This method only returns declaration annotations. * <em>Type annotations</em> in the sense of JLS8 9.7.4 are <em>not</em> returned. * Type annotations can be retrieved from a parameter type * via {@link ITypeBinding#getTypeAnnotations()}. * </p> * * @param paramIndex the index of the parameter of interest * @return the resolved declaration annotations of the <code>paramIndex</code>th parameter, * or an empty list if there are none * @throws ArrayIndexOutOfBoundsException if <code>paramIndex</code> is * not a valid index * @since 3.2 */ public IAnnotationBinding[] getParameterAnnotations(int paramIndex); /** * Returns a list of type bindings representing the formal parameter types, * in declaration order, of this method or constructor. Returns an array of * length 0 if this method or constructor does not takes any parameters. * <p> * Note that the binding for the last parameter type of a vararg method * declaration like <code>void fun(Foo... args)</code> is always for * an array type (i.e., <code>Foo[]</code>) reflecting the the way varargs * get compiled. However, the type binding obtained directly from * the <code>SingleVariableDeclaration</code> for the vararg parameter * is always for the type as written; i.e., the type binding for * <code>Foo</code>. * </p> * <p> * Note: The result does not include synthetic parameters introduced by * inner class emulation. Explicit receiver parameters are also not included. * </p> * * @return a (possibly empty) list of type bindings for the formal * parameters of this method or constructor */ public ITypeBinding[] getParameterTypes(); /** * Returns the type of this method's receiver or <code>null</code> * if there is no receiver declared explicitly. * * @return the type of this method's receiver or <code>null</code> * if there is no receiver declared explicitly. * * @since 3.10 */ public ITypeBinding getDeclaredReceiverType(); /** * Returns the binding for the return type of this method. Returns the * special primitive <code>void</code> return type for constructors. * <p> * For methods, the type binding that is returned contains type annotations * if any. For e.g. the following code would get the type annotations on a * method: <br><br> * <code> IAnnotationBinding[] annots = getReturnType().getTypeAnnotations() </code> * </p> * For a constructor, the returned binding does not include type annotations. * * @return the binding for the return type of this method, or the * <code>void</code> return type for constructors */ public ITypeBinding getReturnType(); /** * Returns a list of type bindings representing the types of the exceptions thrown * by this method or constructor. Returns an array of length 0 if this method * throws no exceptions. The resulting types are in no particular order. * * @return a list of type bindings for exceptions * thrown by this method or constructor */ public ITypeBinding[] getExceptionTypes(); /** * Returns the type parameters of this method or constructor binding. * <p> * Note that type parameters only occur on the binding of the * declaring generic method. Type bindings corresponding to a raw or * parameterized reference to a generic method do not carry type * parameters (they instead have non-empty type arguments * and non-trivial erasure). * </p> * * @return the list of binding for the type variables for the type * parameters of this method, or otherwise the empty list * @see ITypeBinding#isTypeVariable() * @since 3.1 */ public ITypeBinding[] getTypeParameters(); /** * Returns whether this is the binding for an annotation type member. * * @return <code>true</code> iff this is the binding for an annotation type member * and <code>false</code> otherwise * @since 3.2 */ public boolean isAnnotationMember(); /** * Returns whether this method binding represents a declaration of * a generic method. * <p> * Note that type parameters only occur on the binding of the * declaring generic method; e.g., <code>public <T> T identity(T t);</code>. * Method bindings corresponding to a raw or parameterized reference to a generic * method do not carry type parameters (they instead have non-empty type arguments * and non-trivial erasure). * This method is fully equivalent to <code>getTypeParameters().length > 0)</code>. * </p> * <p> * Note that {@link #isGenericMethod()}, * {@link #isParameterizedMethod()}, * and {@link #isRawMethod()} are mutually exclusive. * </p> * * @return <code>true</code> if this method binding represents a * declaration of a generic method, and <code>false</code> otherwise * @see #getTypeParameters() * @since 3.1 */ public boolean isGenericMethod(); /** * Returns whether this method binding represents an instance of * a generic method corresponding to a parameterized method reference. * <p> * Note that {@link #isGenericMethod()}, * {@link #isParameterizedMethod()}, * and {@link #isRawMethod()} are mutually exclusive. * </p> * * @return <code>true</code> if this method binding represents a * an instance of a generic method corresponding to a parameterized * method reference, and <code>false</code> otherwise * @see #getMethodDeclaration() * @see #getTypeArguments() * @since 3.1 */ public boolean isParameterizedMethod(); /** * Returns the type arguments of this generic method instance, or the * empty list for other method bindings. * <p> * Note that type arguments only occur on a method binding that represents * an instance of a generic method corresponding to a raw or parameterized * reference to a generic method. Do not confuse these with type parameters * which only occur on the method binding corresponding directly to the * declaration of a generic method. * </p> * * @return the list of type bindings for the type arguments used to * instantiate the corrresponding generic method, or otherwise the empty list * @see #getMethodDeclaration() * @see #isParameterizedMethod() * @see #isRawMethod() * @since 3.1 */ public ITypeBinding[] getTypeArguments(); /** * Returns the binding for the method declaration corresponding to this * method binding. * <ul> * <li>For parameterized methods ({@link #isParameterizedMethod()}) * and raw methods ({@link #isRawMethod()}), this method returns the binding * for the corresponding generic method.</li> * <li>For references to the method {@link Object#getClass() Object.getClass()}, * returns the binding for the method declaration which is declared to return * <code>Class<?></code> or <code>Class<? extends Object></code>. In the * reference binding, the return type becomes * <code>Class<? extends </code><em>R</em><code>></code>, where <em>R</em> * is the erasure of the static type of the receiver of the method invocation.</li> * <li>For references to a signature polymorphic method from class MethodHandle, * returns the declaration of the method. In the reference binding, the parameter types and * the return type are determined by the concrete invocation context.</li> * <li>For lambda methods, returns the (possibly parameterized) single abstract method * of the functional type.</li> * <li>For other method bindings, this returns the same binding.</li> * </ul> * * @return the method binding * @since 3.1 */ public IMethodBinding getMethodDeclaration(); /** * Returns whether this method binding represents an instance of * a generic method corresponding to a raw method reference. * <p> * Note that {@link #isGenericMethod()}, * {@link #isParameterizedMethod()}, * and {@link #isRawMethod()} are mutually exclusive. * </p> * * @return <code>true</code> if this method binding represents a * an instance of a generic method corresponding to a raw * method reference, and <code>false</code> otherwise * @see #getMethodDeclaration() * @see #getTypeArguments() * @since 3.1 */ public boolean isRawMethod(); /** * Returns whether this method's signature is a subsignature of the given method as * specified in section 8.4.2 of <em>The Java Language Specification, Third Edition</em> (JLS3). * * @return <code>true</code> if this method's signature is a subsignature of the given method * @since 3.1 */ public boolean isSubsignature(IMethodBinding otherMethod); /** * Returns whether this is a variable arity method. * <p> * Note: Variable arity ("varargs") methods were added in JLS3. * </p> * * @return <code>true</code> if this is a variable arity method, * and <code>false</code> otherwise * @since 3.1 */ public boolean isVarargs(); /** * Returns whether this method overrides the given method, * as specified in section 8.4.8.1 of <em>The Java Language * Specification, Third Edition</em> (JLS3). * * @param method the method that is possibly overriden * @return <code>true</code> if this method overrides the given method, * and <code>false</code> otherwise * @since 3.1 */ public boolean overrides(IMethodBinding method); /** * Returns a list of variable bindings representing the synthetic outer * local variables. Returns an empty array for non-lambda expressions or if * this method does not have any synthetic parameters. * * @return a (possibly empty) list of variable bindings for the synthetic * outer locals of this method if this is a lambda expression, else an empty array. * @since 3.18 */ public IVariableBinding[] getSyntheticOuterLocals(); }