/* * Copyright (c) 1996, 2010, 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 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} provides information about, and access to, a single * constructor for a class. * *

{@code Constructor} permits widening conversions to occur when matching the * actual parameters to newInstance() with the underlying * constructor's formal parameters, but throws an * {@code IllegalArgumentException} if a narrowing conversion would occur. * * @param 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 extends AccessibleObject implements GenericDeclaration, Member { private Class 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; // 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 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 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 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 res = new Constructor<>(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} object representing the class that declares * the constructor represented by this {@code Constructor} object. */ public Class getDeclaringClass() { return clazz; } /** * Returns the name of this constructor, as a string. This is * the binary 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} object, as an integer. The * {@code Modifier} class should be used to decode the modifiers. * * @see Modifier */ public int getModifiers() { return modifiers; } /** * 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 the Java Virtual Machine Specification, * 3rd edition * @since 1.5 */ public TypeVariable>[] getTypeParameters() { if (getSignature() != null) { return (TypeVariable>[])getGenericInfo().getTypeParameters(); } else return (TypeVariable>[])new TypeVariable[0]; } /** * Returns an array of {@code Class} objects that represent the formal * parameter types, in declaration order, of the constructor * represented by this {@code Constructor} 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 {@code Type} objects that represent the formal * parameter types, in declaration order, of the method represented by * this {@code Constructor} object. Returns an array of length 0 if the * underlying method takes no parameters. * *

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. * *

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 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} objects that represent the types * of exceptions declared to be thrown by the underlying constructor * represented by this {@code Constructor} object. Returns an array of * length 0 if the constructor declares no exceptions in its {@code throws} 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 {@code Type} objects that represent the * exceptions declared to be thrown by this {@code Constructor} object. * Returns an array of length 0 if the underlying method declares * no exceptions in its {@code throws} clause. * *

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 * {@code throws} clause refers to a non-existent type declaration * @throws MalformedParameterizedTypeException if * the underlying method's {@code throws} 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} against the specified object. * Returns true if the objects are the same. Two {@code Constructor} 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}. 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}. 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: *

     *    public java.util.Hashtable(int,float)
     * 
* *

The only possible modifiers for constructors are the access * modifiers {@code public}, {@code protected} or * {@code private}. 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() & Modifier.constructorModifiers(); 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}, * 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. * * If this constructor was declared to take a variable number of * arguments, instead of denoting the last parameter as * "Type[]", it is denoted as * "Type...". * * 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 "{@code throws}" followed by a * comma-separated list of the thrown exception types. * *

The only possible modifiers for constructors are the access * modifiers {@code public}, {@code protected} or * {@code private}. Only one of these may appear, or none if the * constructor has default (package) access. * * @return a string describing this {@code Constructor}, * include type parameters * * @since 1.5 */ public String toGenericString() { try { StringBuilder sb = new StringBuilder(); int mod = getModifiers() & Modifier.constructorModifiers(); if (mod != 0) { sb.append(Modifier.toString(mod) + " "); } 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("> "); } sb.append(Field.getTypeName(getDeclaringClass())); sb.append("("); Type[] params = getGenericParameterTypes(); for (int j = 0; j < params.length; j++) { String param = (params[j] instanceof Class)? Field.getTypeName((Class)params[j]): (params[j].toString()); 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 + ">"; } } /** * Uses the constructor represented by this {@code Constructor} 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. * *

If the number of formal parameters required by the underlying constructor * is 0, the supplied {@code initargs} array may be of length 0 or null. * *

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 The Java Language * Specification, section 15.9.3. * *

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. * *

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 {@code float} * 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} object * is enforcing 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 {@code true} if this constructor was declared to take * a variable number of arguments; returns {@code false} * otherwise. * * @return {@code true} 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 {@code true} if this constructor is a synthetic * constructor; returns {@code false} 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 getAnnotation(Class annotationClass) { if (annotationClass == null) throw new NullPointerException(); return (T) declaredAnnotations().get(annotationClass); } /** * @since 1.5 */ public Annotation[] getDeclaredAnnotations() { return AnnotationParser.toArray(declaredAnnotations()); } private transient Map, Annotation> declaredAnnotations; private synchronized Map, 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 {@code Constructor} 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; } }