/*
* @(#)Constructor.java 1.56 06/07/11
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.lang.reflect;
import sun.reflect.ConstructorAccessor;
import sun.reflect.Reflection;
import sun.reflect.generics.repository.ConstructorRepository;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.scope.ConstructorScope;
import java.lang.annotation.Annotation;
import java.util.Map;
import sun.reflect.annotation.AnnotationParser;
import java.lang.annotation.AnnotationFormatError;
import java.lang.reflect.Modifier;
/**
* <code>Constructor</code> provides information about, and access to, a single
* constructor for a class.
*
* <p><code>Constructor</code> permits widening conversions to occur when matching the
* actual parameters to newInstance() with the underlying
* constructor's formal parameters, but throws an
* <code>IllegalArgumentException</code> if a narrowing conversion would occur.
*
* @param <T> the class in which the constructor is declared
*
* @see Member
* @see java.lang.Class
* @see java.lang.Class#getConstructors()
* @see java.lang.Class#getConstructor(Class[])
* @see java.lang.Class#getDeclaredConstructors()
*
* @author Kenneth Russell
* @author Nakul Saraiya
*/
public final
class Constructor<T> extends AccessibleObject implements
GenericDeclaration,
Member {
private Class<T> clazz;
private int slot;
private Class[] parameterTypes;
private Class[] exceptionTypes;
private int modifiers;
// Generics and annotations support
private transient String signature;
// generic info repository; lazily initialized
private transient ConstructorRepository genericInfo;
private byte[] annotations;
private byte[] parameterAnnotations;
// For non-public members or members in package-private classes,
// it is necessary to perform somewhat expensive security checks.
// If the security check succeeds for a given class, it will
// always succeed (it is not affected by the granting or revoking
// of permissions); we speed up the check in the common case by
// remembering the last Class for which the check succeeded.
private volatile Class securityCheckCache;
// Modifiers that can be applied to a constructor in source code
private static final int LANGUAGE_MODIFIERS =
Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
// Generics infrastructure
// Accessor for factory
private GenericsFactory getFactory() {
// create scope and factory
return CoreReflectionFactory.make(this, ConstructorScope.make(this));
}
// Accessor for generic info repository
private ConstructorRepository getGenericInfo() {
// lazily initialize repository if necessary
if (genericInfo == null) {
// create and cache generic info repository
genericInfo =
ConstructorRepository.make(getSignature(),
getFactory());
}
return genericInfo; //return cached repository
}
private volatile ConstructorAccessor constructorAccessor;
// For sharing of ConstructorAccessors. This branching structure
// is currently only two levels deep (i.e., one root Constructor
// and potentially many Constructor objects pointing to it.)
private Constructor<T> root;
/**
* Package-private constructor used by ReflectAccess to enable
* instantiation of these objects in Java code from the java.lang
* package via sun.reflect.LangReflectAccess.
*/
Constructor(Class<T> declaringClass,
Class[] parameterTypes,
Class[] checkedExceptions,
int modifiers,
int slot,
String signature,
byte[] annotations,
byte[] parameterAnnotations)
{
this.clazz = declaringClass;
this.parameterTypes = parameterTypes;
this.exceptionTypes = checkedExceptions;
this.modifiers = modifiers;
this.slot = slot;
this.signature = signature;
this.annotations = annotations;
this.parameterAnnotations = parameterAnnotations;
}
/**
* Package-private routine (exposed to java.lang.Class via
* ReflectAccess) which returns a copy of this Constructor. The copy's
* "root" field points to this Constructor.
*/
Constructor<T> copy() {
// This routine enables sharing of ConstructorAccessor objects
// among Constructor objects which refer to the same underlying
// method in the VM. (All of this contortion is only necessary
// because of the "accessibility" bit in AccessibleObject,
// which implicitly requires that new java.lang.reflect
// objects be fabricated for each reflective call on Class
// objects.)
Constructor<T> res = new Constructor<T>(clazz,
parameterTypes,
exceptionTypes, modifiers, slot,
signature,
annotations,
parameterAnnotations);
res.root = this;
// Might as well eagerly propagate this if already present
res.constructorAccessor = constructorAccessor;
return res;
}
/**
* Returns the <code>Class</code> object representing the class that declares
* the constructor represented by this <code>Constructor</code> object.
*/
public Class<T> getDeclaringClass() {
return clazz;
}
/**
* Returns the name of this constructor, as a string. This is
* always the same as the simple name of the constructor's declaring
* class.
*/
public String getName() {
return getDeclaringClass().getName();
}
/**
* Returns the Java language modifiers for the constructor
* represented by this <code>Constructor</code> object, as an integer. The
* <code>Modifier</code> class should be used to decode the modifiers.
*
* @see Modifier
*/
public int getModifiers() {
return modifiers;
}
/**
* Returns an array of <tt>TypeVariable</tt> objects that represent the
* type variables declared by the generic declaration represented by this
* <tt>GenericDeclaration</tt> object, in declaration order. Returns an
* array of length 0 if the underlying generic declaration declares no type
* variables.
*
* @return an array of <tt>TypeVariable</tt> 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 the Java Virtual Machine Specification,
* 3rd edition
* @since 1.5
*/
public TypeVariable<Constructor<T>>[] getTypeParameters() {
if (getSignature() != null) {
return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
} else
return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
}
/**
* Returns an array of <code>Class</code> objects that represent the formal
* parameter types, in declaration order, of the constructor
* represented by this <code>Constructor</code> object. Returns an array of
* length 0 if the underlying constructor takes no parameters.
*
* @return the parameter types for the constructor this object
* represents
*/
public Class<?>[] getParameterTypes() {
return (Class<?>[]) parameterTypes.clone();
}
/**
* Returns an array of <tt>Type</tt> objects that represent the formal
* parameter types, in declaration order, of the method represented by
* this <tt>Constructor</tt> object. Returns an array of length 0 if the
* underlying method takes no parameters.
*
* <p>If a formal parameter type is a parameterized type,
* the <tt>Type</tt> 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 <tt>Type</tt>s that represent the formal
* parameter types of the underlying method, in declaration order
* @throws GenericSignatureFormatError
* if the generic method signature does not conform to the format
* specified in the Java Virtual Machine Specification, 3rd edition
* @throws TypeNotPresentException if any of the parameter
* types of the underlying method refers to a non-existent type
* declaration
* @throws MalformedParameterizedTypeException if any of
* the underlying method's parameter types refer to a parameterized
* type that cannot be instantiated for any reason
* @since 1.5
*/
public Type[] getGenericParameterTypes() {
if (getSignature() != null)
return getGenericInfo().getParameterTypes();
else
return getParameterTypes();
}
/**
* Returns an array of <code>Class</code> objects that represent the types
* of exceptions declared to be thrown by the underlying constructor
* represented by this <code>Constructor</code> object. Returns an array of
* length 0 if the constructor declares no exceptions in its <code>throws</code> clause.
*
* @return the exception types declared as being thrown by the
* constructor this object represents
*/
public Class<?>[] getExceptionTypes() {
return (Class<?>[])exceptionTypes.clone();
}
/**
* Returns an array of <tt>Type</tt> objects that represent the
* exceptions declared to be thrown by this <tt>Constructor</tt> object.
* Returns an array of length 0 if the underlying method declares
* no exceptions in its <tt>throws</tt> clause.
*
* <p>If an exception type is a parameterized type, the <tt>Type</tt>
* object returned for it must accurately reflect the actual type
* parameters used in the source code.
*
* <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 method
* @throws GenericSignatureFormatError
* if the generic method signature does not conform to the format
* specified in the Java Virtual Machine Specification, 3rd edition
* @throws TypeNotPresentException if the underlying method's
* <tt>throws</tt> clause refers to a non-existent type declaration
* @throws MalformedParameterizedTypeException if
* the underlying method's <tt>throws</tt> clause refers to a
* parameterized type that cannot be instantiated for any reason
* @since 1.5
*/
public Type[] getGenericExceptionTypes() {
Type[] result;
if (getSignature() != null &&
( (result = getGenericInfo().getExceptionTypes()).length > 0 ))
return result;
else
return getExceptionTypes();
}
/**
* Compares this <code>Constructor</code> against the specified object.
* Returns true if the objects are the same. Two <code>Constructor</code> objects are
* the same if they were declared by the same class and have the
* same formal parameter types.
*/
public boolean equals(Object obj) {
if (obj != null && obj instanceof Constructor) {
Constructor other = (Constructor)obj;
if (getDeclaringClass() == other.getDeclaringClass()) {
/* Avoid unnecessary cloning */
Class[] params1 = parameterTypes;
Class[] params2 = other.parameterTypes;
if (params1.length == params2.length) {
for (int i = 0; i < params1.length; i++) {
if (params1[i] != params2[i])
return false;
}
return true;
}
}
}
return false;
}
/**
* Returns a hashcode for this <code>Constructor</code>. The hashcode is
* the same as the hashcode for the underlying constructor's
* declaring class name.
*/
public int hashCode() {
return getDeclaringClass().getName().hashCode();
}
/**
* Returns a string describing this <code>Constructor</code>. The string is
* formatted as the constructor access modifiers, if any,
* followed by the fully-qualified name of the declaring class,
* followed by a parenthesized, comma-separated list of the
* constructor's formal parameter types. For example:
* <pre>
* public java.util.Hashtable(int,float)
* </pre>
*
* <p>The only possible modifiers for constructors are the access
* modifiers <tt>public</tt>, <tt>protected</tt> or
* <tt>private</tt>. Only one of these may appear, or none if the
* constructor has default (package) access.
*/
public String toString() {
try {
StringBuffer sb = new StringBuffer();
int mod = getModifiers() & LANGUAGE_MODIFIERS;
if (mod != 0) {
sb.append(Modifier.toString(mod) + " ");
}
sb.append(Field.getTypeName(getDeclaringClass()));
sb.append("(");
Class[] params = parameterTypes; // avoid clone
for (int j = 0; j < params.length; j++) {
sb.append(Field.getTypeName(params[j]));
if (j < (params.length - 1))
sb.append(",");
}
sb.append(")");
Class[] exceptions = exceptionTypes; // avoid clone
if (exceptions.length > 0) {
sb.append(" throws ");
for (int k = 0; k < exceptions.length; k++) {
sb.append(exceptions[k].getName());
if (k < (exceptions.length - 1))
sb.append(",");
}
}
return sb.toString();
} catch (Exception e) {
return "<" + e + ">";
}
}
/**
* Returns a string describing this <code>Constructor</code>,
* including type parameters. The string is formatted as the
* constructor access modifiers, if any, followed by an
* angle-bracketed comma separated list of the constructor's type
* parameters, if any, followed by the fully-qualified name of the
* declaring class, followed by a parenthesized, comma-separated
* list of the constructor's generic formal parameter types. A
* space is used to separate access modifiers from one another and
* from the type parameters or return type. If there are no type
* parameters, the type parameter list is elided; if the type
* parameter list is present, a space separates the list from the
* class name. If the constructor is declared to throw
* exceptions, the parameter list is followed by a space, followed
* by the word "<tt>throws</tt>" followed by a
* comma-separated list of the thrown exception types.
*
* <p>The only possible modifiers for constructors are the access
* modifiers <tt>public</tt>, <tt>protected</tt> or
* <tt>private</tt>. Only one of these may appear, or none if the
* constructor has default (package) access.
*
* @return a string describing this <code>Constructor</code>,
* include type parameters
*
* @since 1.5
*/
public String toGenericString() {
try {
StringBuilder sb = new StringBuilder();
int mod = getModifiers() & LANGUAGE_MODIFIERS;
if (mod != 0) {
sb.append(Modifier.toString(mod) + " ");
}
Type[] typeparms = getTypeParameters();
if (typeparms.length > 0) {
boolean first = true;
sb.append("<");
for(Type typeparm: typeparms) {
if (!first)
sb.append(",");
if (typeparm instanceof Class)
sb.append(((Class)typeparm).getName());
else
sb.append(typeparm.toString());
first = false;
}
sb.append("> ");
}
sb.append(Field.getTypeName(getDeclaringClass()));
sb.append("(");
Type[] params = getGenericParameterTypes();
for (int j = 0; j < params.length; j++) {
sb.append((params[j] instanceof Class)?
Field.getTypeName((Class)params[j]):
(params[j].toString()) );
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 + ">";
}
}
/**
* Uses the constructor represented by this <code>Constructor</code> object to
* create and initialize a new instance of the constructor's
* declaring class, with the specified initialization parameters.
* Individual parameters are automatically unwrapped to match
* primitive formal parameters, and both primitive and reference
* parameters are subject to method invocation conversions as necessary.
*
* <p>If the number of formal parameters required by the underlying constructor
* is 0, the supplied <code>initargs</code> array may be of length 0 or null.
*
* <p>If the constructor's declaring class is an inner class in a
* non-static context, the first argument to the constructor needs
* to be the enclosing instance; see <i>The Java Language
* Specification</i>, section 15.9.3.
*
* <p>If the required access and argument checks succeed and the
* instantiation will proceed, the constructor's declaring class
* is initialized if it has not already been initialized.
*
* <p>If the constructor completes normally, returns the newly
* created and initialized instance.
*
* @param initargs array of objects to be passed as arguments to
* the constructor call; values of primitive types are wrapped in
* a wrapper object of the appropriate type (e.g. a <tt>float</tt>
* in a {@link java.lang.Float Float})
*
* @return a new object created by calling the constructor
* this object represents
*
* @exception IllegalAccessException if this <code>Constructor</code> object
* enforces Java language access control and the underlying
* constructor is inaccessible.
* @exception IllegalArgumentException if the number of actual
* and formal parameters differ; if an unwrapping
* conversion for primitive arguments fails; or if,
* after possible unwrapping, a parameter value
* cannot be converted to the corresponding formal
* parameter type by a method invocation conversion; if
* this constructor pertains to an enum type.
* @exception InstantiationException if the class that declares the
* underlying constructor represents an abstract class.
* @exception InvocationTargetException if the underlying constructor
* throws an exception.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
*/
public T newInstance(Object ... initargs)
throws InstantiationException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException
{
if (!override) {
if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {
Class caller = Reflection.getCallerClass(2);
if (securityCheckCache != caller) {
Reflection.ensureMemberAccess(caller, clazz, null, modifiers);
securityCheckCache = caller;
}
}
}
if ((clazz.getModifiers() & Modifier.ENUM) != 0)
throw new IllegalArgumentException("Cannot reflectively create enum objects");
if (constructorAccessor == null) acquireConstructorAccessor();
return (T) constructorAccessor.newInstance(initargs);
}
/**
* Returns <tt>true</tt> if this constructor was declared to take
* a variable number of arguments; returns <tt>false</tt>
* otherwise.
*
* @return <tt>true</tt> if an only if this constructor was declared to
* take a variable number of arguments.
* @since 1.5
*/
public boolean isVarArgs() {
return (getModifiers() & Modifier.VARARGS) != 0;
}
/**
* Returns <tt>true</tt> if this constructor is a synthetic
* constructor; returns <tt>false</tt> otherwise.
*
* @return true if and only if this constructor is a synthetic
* constructor as defined by the Java Language Specification.
* @since 1.5
*/
public boolean isSynthetic() {
return Modifier.isSynthetic(getModifiers());
}
// NOTE that there is no synchronization used here. It is correct
// (though not efficient) to generate more than one
// ConstructorAccessor for a given Constructor. However, avoiding
// synchronization will probably make the implementation more
// scalable.
private void acquireConstructorAccessor() {
// First check to see if one has been created yet, and take it
// if so.
ConstructorAccessor tmp = null;
if (root != null) tmp = root.getConstructorAccessor();
if (tmp != null) {
constructorAccessor = tmp;
return;
}
// Otherwise fabricate one and propagate it up to the root
tmp = reflectionFactory.newConstructorAccessor(this);
setConstructorAccessor(tmp);
}
// Returns ConstructorAccessor for this Constructor object, not
// looking up the chain to the root
ConstructorAccessor getConstructorAccessor() {
return constructorAccessor;
}
// Sets the ConstructorAccessor for this Constructor object and
// (recursively) its root
void setConstructorAccessor(ConstructorAccessor accessor) {
constructorAccessor = accessor;
// Propagate up
if (root != null) {
root.setConstructorAccessor(accessor);
}
}
int getSlot() {
return slot;
}
String getSignature() {
return signature;
}
byte[] getRawAnnotations() {
return annotations;
}
byte[] getRawParameterAnnotations() {
return parameterAnnotations;
}
/**
* @throws NullPointerException {@inheritDoc}
* @since 1.5
*/
public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
if (annotationClass == null)
throw new NullPointerException();
return (T) declaredAnnotations().get(annotationClass);
}
private static final Annotation[] EMPTY_ANNOTATION_ARRAY=new Annotation[0];
/**
* @since 1.5
*/
public Annotation[] getDeclaredAnnotations() {
return declaredAnnotations().values().toArray(EMPTY_ANNOTATION_ARRAY);
}
private transient Map<Class, Annotation> declaredAnnotations;
private synchronized Map<Class, Annotation> declaredAnnotations() {
if (declaredAnnotations == null) {
declaredAnnotations = AnnotationParser.parseAnnotations(
annotations, sun.misc.SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringClass()),
getDeclaringClass());
}
return declaredAnnotations;
}
/**
* Returns an array of arrays that represent the annotations on the formal
* parameters, in declaration order, of the method represented by
* this <tt>Constructor</tt> object. (Returns an array of length zero if the
* underlying method is parameterless. If the method 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.
*
* @return an array of arrays that represent the annotations on the formal
* parameters, in declaration order, of the method represented by this
* Constructor object
* @since 1.5
*/
public Annotation[][] getParameterAnnotations() {
int numParameters = parameterTypes.length;
if (parameterAnnotations == null)
return new Annotation[numParameters][0];
Annotation[][] result = AnnotationParser.parseParameterAnnotations(
parameterAnnotations,
sun.misc.SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringClass()),
getDeclaringClass());
if (result.length != numParameters) {
Class<?> declaringClass = getDeclaringClass();
if (declaringClass.isEnum() ||
declaringClass.isAnonymousClass() ||
declaringClass.isLocalClass() )
; // Can't do reliable parameter counting
else {
if (!declaringClass.isMemberClass() || // top-level
// Check for the enclosing instance parameter for
// non-static member classes
(declaringClass.isMemberClass() &&
((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
result.length + 1 != numParameters) ) {
throw new AnnotationFormatError(
"Parameter annotations don't match number of parameters");
}
}
}
return result;
}
}
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