JDK8/Java8源码在线阅读
/*
* Copyright (c) 2012, 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
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package java.lang.reflect;
import java.lang.annotation.*;
import java.util.Map;
import java.util.Objects;
import sun.reflect.annotation.AnnotationParser;
import sun.reflect.annotation.AnnotationSupport;
import sun.reflect.annotation.TypeAnnotationParser;
import sun.reflect.annotation.TypeAnnotation;
import sun.reflect.generics.repository.ConstructorRepository;
/**
* A shared superclass for the common functionality of {@link Method}
* and {@link Constructor}.
*
* @since 1.8
*/
public abstract class Executable extends AccessibleObject
implements Member, GenericDeclaration {
/*
* Only grant package-visibility to the constructor.
*/
Executable() {}
/**
* Accessor method to allow code sharing
*/
abstract byte[] getAnnotationBytes();
/**
* Accessor method to allow code sharing
*/
abstract Executable getRoot();
/**
* Does the Executable have generic information.
*/
abstract boolean hasGenericInformation();
abstract ConstructorRepository getGenericInfo();
boolean equalParamTypes(Class<?>[] params1, Class<?>[] params2) {
/* Avoid unnecessary cloning */
if (params1.length == params2.length) {
for (int i = 0; i < params1.length; i++) {
if (params1[i] != params2[i])
return false;
}
return true;
}
return false;
}
Annotation[][] parseParameterAnnotations(byte[] parameterAnnotations) {
return AnnotationParser.parseParameterAnnotations(
parameterAnnotations,
sun.misc.SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringClass()),
getDeclaringClass());
}
void separateWithCommas(Class<?>[] types, StringBuilder sb) {
for (int j = 0; j < types.length; j++) {
sb.append(types[j].getTypeName());
if (j < (types.length - 1))
sb.append(",");
}
}
void printModifiersIfNonzero(StringBuilder sb, int mask, boolean isDefault) {
int mod = getModifiers() & mask;
if (mod != 0 && !isDefault) {
sb.append(Modifier.toString(mod)).append(' ');
} else {
int access_mod = mod & Modifier.ACCESS_MODIFIERS;
if (access_mod != 0)
sb.append(Modifier.toString(access_mod)).append(' ');
if (isDefault)
sb.append("default ");
mod = (mod & ~Modifier.ACCESS_MODIFIERS);
if (mod != 0)
sb.append(Modifier.toString(mod)).append(' ');
}
}
String sharedToString(int modifierMask,
boolean isDefault,
Class<?>[] parameterTypes,
Class<?>[] exceptionTypes) {
try {
StringBuilder sb = new StringBuilder();
printModifiersIfNonzero(sb, modifierMask, isDefault);
specificToStringHeader(sb);
sb.append('(');
separateWithCommas(parameterTypes, sb);
sb.append(')');
if (exceptionTypes.length > 0) {
sb.append(" throws ");
separateWithCommas(exceptionTypes, sb);
}
return sb.toString();
} catch (Exception e) {
return "<" + e + ">";
}
}
/**
* Generate toString header information specific to a method or
* constructor.
*/
abstract void specificToStringHeader(StringBuilder sb);
String sharedToGenericString(int modifierMask, boolean isDefault) {
try {
StringBuilder sb = new StringBuilder();
printModifiersIfNonzero(sb, modifierMask, isDefault);
TypeVariable<?>[] typeparms = getTypeParameters();
if (typeparms.length > 0) {
boolean first = true;
sb.append('<');
for(TypeVariable<?> typeparm: typeparms) {
if (!first)
sb.append(',');
// Class objects can't occur here; no need to test
// and call Class.getName().
sb.append(typeparm.toString());
first = false;
}
sb.append("> ");
}
specificToGenericStringHeader(sb);
sb.append('(');
Type[] params = getGenericParameterTypes();
for (int j = 0; j < params.length; j++) {
String param = params[j].getTypeName();
if (isVarArgs() && (j == params.length - 1)) // replace T[] with T...
param = param.replaceFirst("\\[\\]$", "...");
sb.append(param);
if (j < (params.length - 1))
sb.append(',');
}
sb.append(')');
Type[] exceptions = getGenericExceptionTypes();
if (exceptions.length > 0) {
sb.append(" throws ");
for (int k = 0; k < exceptions.length; k++) {
sb.append((exceptions[k] instanceof Class)?
((Class)exceptions[k]).getName():
exceptions[k].toString());
if (k < (exceptions.length - 1))
sb.append(',');
}
}
return sb.toString();
} catch (Exception e) {
return "<" + e + ">";
}
}
/**
* Generate toGenericString header information specific to a
* method or constructor.
*/
abstract void specificToGenericStringHeader(StringBuilder sb);
/**
* Returns the {@code Class} object representing the class or interface
* that declares the executable represented by this object.
*/
public abstract Class<?> getDeclaringClass();
/**
* Returns the name of the executable represented by this object.
*/
public abstract String getName();
/**
* Returns the Java language {@linkplain Modifier modifiers} for
* the executable represented by this object.
*/
public abstract int getModifiers();
/**
* Returns an array of {@code TypeVariable} objects that represent the
* type variables declared by the generic declaration represented by this
* {@code GenericDeclaration} object, in declaration order. Returns an
* array of length 0 if the underlying generic declaration declares no type
* variables.
*
* @return an array of {@code TypeVariable} objects that represent
* the type variables declared by this generic declaration
* @throws GenericSignatureFormatError if the generic
* signature of this generic declaration does not conform to
* the format specified in
* <cite>The Java™ Virtual Machine Specification</cite>
*/
public abstract TypeVariable<?>[] getTypeParameters();
/**
* Returns an array of {@code Class} objects that represent the formal
* parameter types, in declaration order, of the executable
* represented by this object. Returns an array of length
* 0 if the underlying executable takes no parameters.
*
* @return the parameter types for the executable this object
* represents
*/
public abstract Class<?>[] getParameterTypes();
/**
* Returns the number of formal parameters (whether explicitly
* declared or implicitly declared or neither) for the executable
* represented by this object.
*
* @since 1.8
* @return The number of formal parameters for the executable this
* object represents
*/
public int getParameterCount() {
throw new AbstractMethodError();
}
/**
* Returns an array of {@code Type} objects that represent the formal
* parameter types, in declaration order, of the executable represented by
* this object. Returns an array of length 0 if the
* underlying executable takes no parameters.
*
* <p>If a formal parameter type is a parameterized type,
* the {@code Type} object returned for it must accurately reflect
* the actual type parameters used in the source code.
*
* <p>If a formal parameter type is a type variable or a parameterized
* type, it is created. Otherwise, it is resolved.
*
* @return an array of {@code Type}s that represent the formal
* parameter types of the underlying executable, in declaration order
* @throws GenericSignatureFormatError
* if the generic method signature does not conform to the format
* specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @throws TypeNotPresentException if any of the parameter
* types of the underlying executable refers to a non-existent type
* declaration
* @throws MalformedParameterizedTypeException if any of
* the underlying executable's parameter types refer to a parameterized
* type that cannot be instantiated for any reason
*/
public Type[] getGenericParameterTypes() {
if (hasGenericInformation())
return getGenericInfo().getParameterTypes();
else
return getParameterTypes();
}
/**
* Behaves like {@code getGenericParameterTypes}, but returns type
* information for all parameters, including synthetic parameters.
*/
Type[] getAllGenericParameterTypes() {
final boolean genericInfo = hasGenericInformation();
// Easy case: we don't have generic parameter information. In
// this case, we just return the result of
// getParameterTypes().
if (!genericInfo) {
return getParameterTypes();
} else {
final boolean realParamData = hasRealParameterData();
final Type[] genericParamTypes = getGenericParameterTypes();
final Type[] nonGenericParamTypes = getParameterTypes();
final Type[] out = new Type[nonGenericParamTypes.length];
final Parameter[] params = getParameters();
int fromidx = 0;
// If we have real parameter data, then we use the
// synthetic and mandate flags to our advantage.
if (realParamData) {
for (int i = 0; i < out.length; i++) {
final Parameter param = params[i];
if (param.isSynthetic() || param.isImplicit()) {
// If we hit a synthetic or mandated parameter,
// use the non generic parameter info.
out[i] = nonGenericParamTypes[i];
} else {
// Otherwise, use the generic parameter info.
out[i] = genericParamTypes[fromidx];
fromidx++;
}
}
} else {
// Otherwise, use the non-generic parameter data.
// Without method parameter reflection data, we have
// no way to figure out which parameters are
// synthetic/mandated, thus, no way to match up the
// indexes.
return genericParamTypes.length == nonGenericParamTypes.length ?
genericParamTypes : nonGenericParamTypes;
}
return out;
}
}
/**
* Returns an array of {@code Parameter} objects that represent
* all the parameters to the underlying executable represented by
* this object. Returns an array of length 0 if the executable
* has no parameters.
*
* <p>The parameters of the underlying executable do not necessarily
* have unique names, or names that are legal identifiers in the
* Java programming language (JLS 3.8).
*
* @since 1.8
* @throws MalformedParametersException if the class file contains
* a MethodParameters attribute that is improperly formatted.
* @return an array of {@code Parameter} objects representing all
* the parameters to the executable this object represents.
*/
public Parameter[] getParameters() {
// TODO: This may eventually need to be guarded by security
// mechanisms similar to those in Field, Method, etc.
//
// Need to copy the cached array to prevent users from messing
// with it. Since parameters are immutable, we can
// shallow-copy.
return privateGetParameters().clone();
}
private Parameter[] synthesizeAllParams() {
final int realparams = getParameterCount();
final Parameter[] out = new Parameter[realparams];
for (int i = 0; i < realparams; i++)
// TODO: is there a way to synthetically derive the
// modifiers? Probably not in the general case, since
// we'd have no way of knowing about them, but there
// may be specific cases.
out[i] = new Parameter("arg" + i, 0, this, i);
return out;
}
private void verifyParameters(final Parameter[] parameters) {
final int mask = Modifier.FINAL | Modifier.SYNTHETIC | Modifier.MANDATED;
if (getParameterTypes().length != parameters.length)
throw new MalformedParametersException("Wrong number of parameters in MethodParameters attribute");
for (Parameter parameter : parameters) {
final String name = parameter.getRealName();
final int mods = parameter.getModifiers();
if (name != null) {
if (name.isEmpty() || name.indexOf('.') != -1 ||
name.indexOf(';') != -1 || name.indexOf('[') != -1 ||
name.indexOf('/') != -1) {
throw new MalformedParametersException("Invalid parameter name \"" + name + "\"");
}
}
if (mods != (mods & mask)) {
throw new MalformedParametersException("Invalid parameter modifiers");
}
}
}
private Parameter[] privateGetParameters() {
// Use tmp to avoid multiple writes to a volatile.
Parameter[] tmp = parameters;
if (tmp == null) {
// Otherwise, go to the JVM to get them
try {
tmp = getParameters0();
} catch(IllegalArgumentException e) {
// Rethrow ClassFormatErrors
throw new MalformedParametersException("Invalid constant pool index");
}
// If we get back nothing, then synthesize parameters
if (tmp == null) {
hasRealParameterData = false;
tmp = synthesizeAllParams();
} else {
hasRealParameterData = true;
verifyParameters(tmp);
}
parameters = tmp;
}
return tmp;
}
boolean hasRealParameterData() {
// If this somehow gets called before parameters gets
// initialized, force it into existence.
if (parameters == null) {
privateGetParameters();
}
return hasRealParameterData;
}
private transient volatile boolean hasRealParameterData;
private transient volatile Parameter[] parameters;
private native Parameter[] getParameters0();
native byte[] getTypeAnnotationBytes0();
// Needed by reflectaccess
byte[] getTypeAnnotationBytes() {
return getTypeAnnotationBytes0();
}
/**
* Returns an array of {@code Class} objects that represent the
* types of exceptions declared to be thrown by the underlying
* executable represented by this object. Returns an array of
* length 0 if the executable declares no exceptions in its {@code
* throws} clause.
*
* @return the exception types declared as being thrown by the
* executable this object represents
*/
public abstract Class<?>[] getExceptionTypes();
/**
* Returns an array of {@code Type} objects that represent the
* exceptions declared to be thrown by this executable object.
* Returns an array of length 0 if the underlying executable declares
* no exceptions in its {@code throws} clause.
*
* <p>If an exception type is a type variable or a parameterized
* type, it is created. Otherwise, it is resolved.
*
* @return an array of Types that represent the exception types
* thrown by the underlying executable
* @throws GenericSignatureFormatError
* if the generic method signature does not conform to the format
* specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @throws TypeNotPresentException if the underlying executable's
* {@code throws} clause refers to a non-existent type declaration
* @throws MalformedParameterizedTypeException if
* the underlying executable's {@code throws} clause refers to a
* parameterized type that cannot be instantiated for any reason
*/
public Type[] getGenericExceptionTypes() {
Type[] result;
if (hasGenericInformation() &&
((result = getGenericInfo().getExceptionTypes()).length > 0))
return result;
else
return getExceptionTypes();
}
/**
* Returns a string describing this {@code Executable}, including
* any type parameters.
* @return a string describing this {@code Executable}, including
* any type parameters
*/
public abstract String toGenericString();
/**
* Returns {@code true} if this executable was declared to take a
* variable number of arguments; returns {@code false} otherwise.
*
* @return {@code true} if an only if this executable was declared
* to take a variable number of arguments.
*/
public boolean isVarArgs() {
return (getModifiers() & Modifier.VARARGS) != 0;
}
/**
* Returns {@code true} if this executable is a synthetic
* construct; returns {@code false} otherwise.
*
* @return true if and only if this executable is a synthetic
* construct as defined by
* <cite>The Java™ Language Specification</cite>.
* @jls 13.1 The Form of a Binary
*/
public boolean isSynthetic() {
return Modifier.isSynthetic(getModifiers());
}
/**
* Returns an array of arrays of {@code Annotation}s that
* represent the annotations on the formal parameters, in
* declaration order, of the {@code Executable} represented by
* this object. Synthetic and mandated parameters (see
* explanation below), such as the outer "this" parameter to an
* inner class constructor will be represented in the returned
* array. If the executable has no parameters (meaning no formal,
* no synthetic, and no mandated parameters), a zero-length array
* will be returned. If the {@code Executable} has one or more
* parameters, a nested array of length zero is returned for each
* parameter with no annotations. The annotation objects contained
* in the returned arrays are serializable. The caller of this
* method is free to modify the returned arrays; it will have no
* effect on the arrays returned to other callers.
*
* A compiler may add extra parameters that are implicitly
* declared in source ("mandated"), as well as parameters that
* are neither implicitly nor explicitly declared in source
* ("synthetic") to the parameter list for a method. See {@link
* java.lang.reflect.Parameter} for more information.
*
* @see java.lang.reflect.Parameter
* @see java.lang.reflect.Parameter#getAnnotations
* @return an array of arrays that represent the annotations on
* the formal and implicit parameters, in declaration order, of
* the executable represented by this object
*/
public abstract Annotation[][] getParameterAnnotations();
Annotation[][] sharedGetParameterAnnotations(Class<?>[] parameterTypes,
byte[] parameterAnnotations) {
int numParameters = parameterTypes.length;
if (parameterAnnotations == null)
return new Annotation[numParameters][0];
Annotation[][] result = parseParameterAnnotations(parameterAnnotations);
if (result.length != numParameters)
handleParameterNumberMismatch(result.length, numParameters);
return result;
}
abstract void handleParameterNumberMismatch(int resultLength, int numParameters);
/**
* {@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}
* @since 1.8
*/
@Override
public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {
Objects.requireNonNull(annotationClass);
return AnnotationSupport.getDirectlyAndIndirectlyPresent(declaredAnnotations(), annotationClass);
}
/**
* {@inheritDoc}
*/
public Annotation[] getDeclaredAnnotations() {
return AnnotationParser.toArray(declaredAnnotations());
}
private transient Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
private synchronized Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {
if (declaredAnnotations == null) {
Executable root = getRoot();
if (root != null) {
declaredAnnotations = root.declaredAnnotations();
} else {
declaredAnnotations = AnnotationParser.parseAnnotations(
getAnnotationBytes(),
sun.misc.SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringClass()),
getDeclaringClass());
}
}
return declaredAnnotations;
}
/**
* Returns an {@code AnnotatedType} object that represents the use of a type to
* specify the return type of the method/constructor represented by this
* Executable.
*
* If this {@code Executable} object represents a constructor, the {@code
* AnnotatedType} object represents the type of the constructed object.
*
* If this {@code Executable} object represents a method, the {@code
* AnnotatedType} object represents the use of a type to specify the return
* type of the method.
*
* @return an object representing the return type of the method
* or constructor represented by this {@code Executable}
*
* @since 1.8
*/
public abstract AnnotatedType getAnnotatedReturnType();
/* Helper for subclasses of Executable.
*
* Returns an AnnotatedType object that represents the use of a type to
* specify the return type of the method/constructor represented by this
* Executable.
*
* @since 1.8
*/
AnnotatedType getAnnotatedReturnType0(Type returnType) {
return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
sun.misc.SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringClass()),
this,
getDeclaringClass(),
returnType,
TypeAnnotation.TypeAnnotationTarget.METHOD_RETURN);
}
/**
* Returns an {@code AnnotatedType} object that represents the use of a
* type to specify the receiver type of the method/constructor represented
* by this Executable object. The receiver type of a method/constructor is
* available only if the method/constructor has a <em>receiver
* parameter</em> (JLS 8.4.1).
*
* If this {@code Executable} object represents a constructor or instance
* method that does not have a receiver parameter, or has a receiver
* parameter with no annotations on its type, then the return value is an
* {@code AnnotatedType} object representing an element with no
* annotations.
*
* If this {@code Executable} object represents a static method, then the
* return value is null.
*
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