src.java.lang.reflect.Parameter Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of android-all Show documentation
Show all versions of android-all Show documentation
A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* 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 dalvik.annotation.optimization.FastNative;
import java.lang.annotation.*;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import libcore.reflect.AnnotatedElements;
/**
* 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 {
// Android-changed: Extensive modifications made throughout the class for ART.
// Android-removed: Type annotations runtime code. Not supported on Android.
// Android-removed: Annotation retrieval is implemented natively in ART.
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;
}
// Android-changed: Removed references in javadoc to the class file format.
/**
* Returns true if the parameter has a name; returns false otherwise.
* Whether a parameter has a name is determined by compiler options
* and whether the parameter is synthesized.
*
* @return true if and only if the parameter has a name
*/
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 The Java™ Language
* Specification, 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 paramete 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 = null;
/**
* 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;
}
private transient volatile Class parameterClassCache = null;
/**
* 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 The Java™ Language
* Specification.
*/
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
* The Java™ Language Specification.
*/
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 getAnnotation(Class annotationClass) {
Objects.requireNonNull(annotationClass);
// Android-changed: getAnnotation(Class) Uses native code to obtain annotation information.
return getAnnotationNative(executable, index, annotationClass);
}
// Android-added: getAnnotation(Class) Uses native code to obtain annotation information.
@FastNative
private static native A getAnnotationNative(
Executable executable, int parameterIndex, Class annotationType);
/**
* {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
@Override
public T[] getAnnotationsByType(Class annotationClass) {
// Android-changed: getAnnotationsByType(Class), Android uses AnnotatedElements instead.
return AnnotatedElements.getDirectOrIndirectAnnotationsByType(this, annotationClass);
}
/**
* {@inheritDoc}
*/
public Annotation[] getDeclaredAnnotations() {
return executable.getParameterAnnotations()[index];
}
/**
* @throws NullPointerException {@inheritDoc}
*/
public T getDeclaredAnnotation(Class 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[] getDeclaredAnnotationsByType(Class 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();
}
}