| /* |
| * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package java.lang.reflect; |
| |
| import java.lang.annotation.*; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Objects; |
| import sun.reflect.annotation.AnnotationSupport; |
| |
| /** |
| * Information about method parameters. |
| * |
| * A {@code Parameter} provides information about method parameters, |
| * including its name and modifiers. It also provides an alternate |
| * means of obtaining attributes for the parameter. |
| * |
| * @since 1.8 |
| */ |
| public final class Parameter implements AnnotatedElement { |
| |
| private final String name; |
| private final int modifiers; |
| private final Executable executable; |
| private final int index; |
| |
| /** |
| * Package-private constructor for {@code Parameter}. |
| * |
| * If method parameter data is present in the classfile, then the |
| * JVM creates {@code Parameter} objects directly. If it is |
| * absent, however, then {@code Executable} uses this constructor |
| * to synthesize them. |
| * |
| * @param name The name of the parameter. |
| * @param modifiers The modifier flags for the parameter. |
| * @param executable The executable which defines this parameter. |
| * @param index The index of the parameter. |
| */ |
| Parameter(String name, |
| int modifiers, |
| Executable executable, |
| int index) { |
| this.name = name; |
| this.modifiers = modifiers; |
| this.executable = executable; |
| this.index = index; |
| } |
| |
| /** |
| * Compares based on the executable and the index. |
| * |
| * @param obj The object to compare. |
| * @return Whether or not this is equal to the argument. |
| */ |
| public boolean equals(Object obj) { |
| if(obj instanceof Parameter) { |
| Parameter other = (Parameter)obj; |
| return (other.executable.equals(executable) && |
| other.index == index); |
| } |
| return false; |
| } |
| |
| /** |
| * Returns a hash code based on the executable's hash code and the |
| * index. |
| * |
| * @return A hash code based on the executable's hash code. |
| */ |
| public int hashCode() { |
| return executable.hashCode() ^ index; |
| } |
| |
| /** |
| * Returns true if the parameter has a name according to the class |
| * file; returns false otherwise. Whether a parameter has a name |
| * is determined by the {@literal MethodParameters} attribute of |
| * the method which declares the parameter. |
| * |
| * @return true if and only if the parameter has a name according |
| * to the class file. |
| */ |
| public boolean isNamePresent() { |
| return executable.hasRealParameterData() && name != null; |
| } |
| |
| /** |
| * Returns a string describing this parameter. The format is the |
| * modifiers for the parameter, if any, in canonical order as |
| * recommended by <cite>The Java™ Language |
| * Specification</cite>, followed by the fully- qualified type of |
| * the parameter (excluding the last [] if the parameter is |
| * variable arity), followed by "..." if the parameter is variable |
| * arity, followed by a space, followed by the name of the |
| * parameter. |
| * |
| * @return A string representation of the parameter and associated |
| * information. |
| */ |
| public String toString() { |
| final StringBuilder sb = new StringBuilder(); |
| final Type type = getParameterizedType(); |
| final String typename = type.getTypeName(); |
| |
| sb.append(Modifier.toString(getModifiers())); |
| |
| if(0 != modifiers) |
| sb.append(' '); |
| |
| if(isVarArgs()) |
| sb.append(typename.replaceFirst("\\[\\]$", "...")); |
| else |
| sb.append(typename); |
| |
| sb.append(' '); |
| sb.append(getName()); |
| |
| return sb.toString(); |
| } |
| |
| /** |
| * Return the {@code Executable} which declares this parameter. |
| * |
| * @return The {@code Executable} declaring this parameter. |
| */ |
| public Executable getDeclaringExecutable() { |
| return executable; |
| } |
| |
| /** |
| * Get the modifier flags for this the parameter represented by |
| * this {@code Parameter} object. |
| * |
| * @return The modifier flags for this parameter. |
| */ |
| public int getModifiers() { |
| return modifiers; |
| } |
| |
| /** |
| * Returns the name of the parameter. If the parameter's name is |
| * {@linkplain #isNamePresent() present}, then this method returns |
| * the name provided by the class file. Otherwise, this method |
| * synthesizes a name of the form argN, where N is the index of |
| * the parameter in the descriptor of the method which declares |
| * the parameter. |
| * |
| * @return The name of the parameter, either provided by the class |
| * file or synthesized if the class file does not provide |
| * a name. |
| */ |
| public String getName() { |
| // Note: empty strings as parameter names are now outlawed. |
| // The .equals("") is for compatibility with current JVM |
| // behavior. It may be removed at some point. |
| if(name == null || name.equals("")) |
| return "arg" + index; |
| else |
| return name; |
| } |
| |
| // Package-private accessor to the real name field. |
| String getRealName() { |
| return name; |
| } |
| |
| /** |
| * Returns a {@code Type} object that identifies the parameterized |
| * type for the parameter represented by this {@code Parameter} |
| * object. |
| * |
| * @return a {@code Type} object identifying the parameterized |
| * type of the parameter represented by this object |
| */ |
| public Type getParameterizedType() { |
| Type tmp = parameterTypeCache; |
| if (null == tmp) { |
| tmp = executable.getAllGenericParameterTypes()[index]; |
| parameterTypeCache = tmp; |
| } |
| |
| return tmp; |
| } |
| |
| private transient volatile Type parameterTypeCache; |
| |
| /** |
| * Returns a {@code Class} object that identifies the |
| * declared type for the parameter represented by this |
| * {@code Parameter} object. |
| * |
| * @return a {@code Class} object identifying the declared |
| * type of the parameter represented by this object |
| */ |
| public Class<?> getType() { |
| Class<?> tmp = parameterClassCache; |
| if (null == tmp) { |
| tmp = executable.getParameterTypes()[index]; |
| parameterClassCache = tmp; |
| } |
| return tmp; |
| } |
| |
| /** |
| * Returns an AnnotatedType object that represents the use of a type to |
| * specify the type of the formal parameter represented by this Parameter. |
| * |
| * @return an {@code AnnotatedType} object representing the use of a type |
| * to specify the type of the formal parameter represented by this |
| * Parameter |
| */ |
| public AnnotatedType getAnnotatedType() { |
| // no caching for now |
| return executable.getAnnotatedParameterTypes()[index]; |
| } |
| |
| private transient volatile Class<?> parameterClassCache; |
| |
| /** |
| * Returns {@code true} if this parameter is implicitly declared |
| * in source code; returns {@code false} otherwise. |
| * |
| * @return true if and only if this parameter is implicitly |
| * declared as defined by <cite>The Java™ Language |
| * Specification</cite>. |
| */ |
| public boolean isImplicit() { |
| return Modifier.isMandated(getModifiers()); |
| } |
| |
| /** |
| * Returns {@code true} if this parameter is neither implicitly |
| * nor explicitly declared in source code; returns {@code false} |
| * otherwise. |
| * |
| * @jls 13.1 The Form of a Binary |
| * @return true if and only if this parameter is a synthetic |
| * construct as defined by |
| * <cite>The Java™ Language Specification</cite>. |
| */ |
| public boolean isSynthetic() { |
| return Modifier.isSynthetic(getModifiers()); |
| } |
| |
| /** |
| * Returns {@code true} if this parameter represents a variable |
| * argument list; returns {@code false} otherwise. |
| * |
| * @return {@code true} if an only if this parameter represents a |
| * variable argument list. |
| */ |
| public boolean isVarArgs() { |
| return executable.isVarArgs() && |
| index == executable.getParameterCount() - 1; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| */ |
| public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { |
| Objects.requireNonNull(annotationClass); |
| return annotationClass.cast(declaredAnnotations().get(annotationClass)); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| */ |
| @Override |
| public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) { |
| Objects.requireNonNull(annotationClass); |
| |
| return AnnotationSupport.getDirectlyAndIndirectlyPresent(declaredAnnotations(), annotationClass); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public Annotation[] getDeclaredAnnotations() { |
| return executable.getParameterAnnotations()[index]; |
| } |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| */ |
| public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) { |
| // Only annotations on classes are inherited, for all other |
| // objects getDeclaredAnnotation is the same as |
| // getAnnotation. |
| return getAnnotation(annotationClass); |
| } |
| |
| /** |
| * @throws NullPointerException {@inheritDoc} |
| */ |
| @Override |
| public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) { |
| // Only annotations on classes are inherited, for all other |
| // objects getDeclaredAnnotations is the same as |
| // getAnnotations. |
| return getAnnotationsByType(annotationClass); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public Annotation[] getAnnotations() { |
| return getDeclaredAnnotations(); |
| } |
| |
| private transient Map<Class<? extends Annotation>, Annotation> declaredAnnotations; |
| |
| private synchronized Map<Class<? extends Annotation>, Annotation> declaredAnnotations() { |
| if(null == declaredAnnotations) { |
| declaredAnnotations = new HashMap<>(); |
| for (Annotation a : getDeclaredAnnotations()) |
| declaredAnnotations.put(a.annotationType(), a); |
| } |
| return declaredAnnotations; |
| } |
| |
| } |