| /* |
| * Copyright (c) 2008, 2015, 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.invoke; |
| |
| import sun.invoke.util.Wrapper; |
| import java.lang.ref.WeakReference; |
| import java.lang.ref.Reference; |
| import java.lang.ref.ReferenceQueue; |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Objects; |
| import java.util.StringJoiner; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.ConcurrentHashMap; |
| import sun.invoke.util.BytecodeDescriptor; |
| import static java.lang.invoke.MethodHandleStatics.*; |
| import sun.invoke.util.VerifyType; |
| |
| /** |
| * A method type represents the arguments and return type accepted and |
| * returned by a method handle, or the arguments and return type passed |
| * and expected by a method handle caller. Method types must be properly |
| * matched between a method handle and all its callers, |
| * and the JVM's operations enforce this matching at, specifically |
| * during calls to {@link MethodHandle#invokeExact MethodHandle.invokeExact} |
| * and {@link MethodHandle#invoke MethodHandle.invoke}, and during execution |
| * of {@code invokedynamic} instructions. |
| * <p> |
| * The structure is a return type accompanied by any number of parameter types. |
| * The types (primitive, {@code void}, and reference) are represented by {@link Class} objects. |
| * (For ease of exposition, we treat {@code void} as if it were a type. |
| * In fact, it denotes the absence of a return type.) |
| * <p> |
| * All instances of {@code MethodType} are immutable. |
| * Two instances are completely interchangeable if they compare equal. |
| * Equality depends on pairwise correspondence of the return and parameter types and on nothing else. |
| * <p> |
| * This type can be created only by factory methods. |
| * All factory methods may cache values, though caching is not guaranteed. |
| * Some factory methods are static, while others are virtual methods which |
| * modify precursor method types, e.g., by changing a selected parameter. |
| * <p> |
| * Factory methods which operate on groups of parameter types |
| * are systematically presented in two versions, so that both Java arrays and |
| * Java lists can be used to work with groups of parameter types. |
| * The query methods {@code parameterArray} and {@code parameterList} |
| * also provide a choice between arrays and lists. |
| * <p> |
| * {@code MethodType} objects are sometimes derived from bytecode instructions |
| * such as {@code invokedynamic}, specifically from the type descriptor strings associated |
| * with the instructions in a class file's constant pool. |
| * <p> |
| * Like classes and strings, method types can also be represented directly |
| * in a class file's constant pool as constants. |
| * A method type may be loaded by an {@code ldc} instruction which refers |
| * to a suitable {@code CONSTANT_MethodType} constant pool entry. |
| * The entry refers to a {@code CONSTANT_Utf8} spelling for the descriptor string. |
| * (For full details on method type constants, |
| * see sections 4.4.8 and 5.4.3.5 of the Java Virtual Machine Specification.) |
| * <p> |
| * When the JVM materializes a {@code MethodType} from a descriptor string, |
| * all classes named in the descriptor must be accessible, and will be loaded. |
| * (But the classes need not be initialized, as is the case with a {@code CONSTANT_Class}.) |
| * This loading may occur at any time before the {@code MethodType} object is first derived. |
| * @author John Rose, JSR 292 EG |
| */ |
| public final |
| class MethodType implements java.io.Serializable { |
| private static final long serialVersionUID = 292L; // {rtype, {ptype...}} |
| |
| // The rtype and ptypes fields define the structural identity of the method type: |
| private final Class<?> rtype; |
| private final Class<?>[] ptypes; |
| |
| // The remaining fields are caches of various sorts: |
| private @Stable MethodTypeForm form; // erased form, plus cached data about primitives |
| private @Stable MethodType wrapAlt; // alternative wrapped/unwrapped version |
| private @Stable Invokers invokers; // cache of handy higher-order adapters |
| private @Stable String methodDescriptor; // cache for toMethodDescriptorString |
| |
| /** |
| * Check the given parameters for validity and store them into the final fields. |
| */ |
| private MethodType(Class<?> rtype, Class<?>[] ptypes, boolean trusted) { |
| checkRtype(rtype); |
| checkPtypes(ptypes); |
| this.rtype = rtype; |
| // defensively copy the array passed in by the user |
| this.ptypes = trusted ? ptypes : Arrays.copyOf(ptypes, ptypes.length); |
| } |
| |
| /** |
| * Construct a temporary unchecked instance of MethodType for use only as a key to the intern table. |
| * Does not check the given parameters for validity, and must be discarded after it is used as a searching key. |
| * The parameters are reversed for this constructor, so that it is not accidentally used. |
| */ |
| private MethodType(Class<?>[] ptypes, Class<?> rtype) { |
| this.rtype = rtype; |
| this.ptypes = ptypes; |
| } |
| |
| /*trusted*/ MethodTypeForm form() { return form; } |
| /*trusted*/ Class<?> rtype() { return rtype; } |
| /*trusted*/ Class<?>[] ptypes() { return ptypes; } |
| |
| void setForm(MethodTypeForm f) { form = f; } |
| |
| /** This number, mandated by the JVM spec as 255, |
| * is the maximum number of <em>slots</em> |
| * that any Java method can receive in its argument list. |
| * It limits both JVM signatures and method type objects. |
| * The longest possible invocation will look like |
| * {@code staticMethod(arg1, arg2, ..., arg255)} or |
| * {@code x.virtualMethod(arg1, arg2, ..., arg254)}. |
| */ |
| /*non-public*/ static final int MAX_JVM_ARITY = 255; // this is mandated by the JVM spec. |
| |
| /** This number is the maximum arity of a method handle, 254. |
| * It is derived from the absolute JVM-imposed arity by subtracting one, |
| * which is the slot occupied by the method handle itself at the |
| * beginning of the argument list used to invoke the method handle. |
| * The longest possible invocation will look like |
| * {@code mh.invoke(arg1, arg2, ..., arg254)}. |
| */ |
| // Issue: Should we allow MH.invokeWithArguments to go to the full 255? |
| /*non-public*/ static final int MAX_MH_ARITY = MAX_JVM_ARITY-1; // deduct one for mh receiver |
| |
| /** This number is the maximum arity of a method handle invoker, 253. |
| * It is derived from the absolute JVM-imposed arity by subtracting two, |
| * which are the slots occupied by invoke method handle, and the |
| * target method handle, which are both at the beginning of the argument |
| * list used to invoke the target method handle. |
| * The longest possible invocation will look like |
| * {@code invokermh.invoke(targetmh, arg1, arg2, ..., arg253)}. |
| */ |
| /*non-public*/ static final int MAX_MH_INVOKER_ARITY = MAX_MH_ARITY-1; // deduct one more for invoker |
| |
| private static void checkRtype(Class<?> rtype) { |
| Objects.requireNonNull(rtype); |
| } |
| private static void checkPtype(Class<?> ptype) { |
| Objects.requireNonNull(ptype); |
| if (ptype == void.class) |
| throw newIllegalArgumentException("parameter type cannot be void"); |
| } |
| /** Return number of extra slots (count of long/double args). */ |
| private static int checkPtypes(Class<?>[] ptypes) { |
| int slots = 0; |
| for (Class<?> ptype : ptypes) { |
| checkPtype(ptype); |
| if (ptype == double.class || ptype == long.class) { |
| slots++; |
| } |
| } |
| checkSlotCount(ptypes.length + slots); |
| return slots; |
| } |
| static void checkSlotCount(int count) { |
| assert((MAX_JVM_ARITY & (MAX_JVM_ARITY+1)) == 0); |
| // MAX_JVM_ARITY must be power of 2 minus 1 for following code trick to work: |
| if ((count & MAX_JVM_ARITY) != count) |
| throw newIllegalArgumentException("bad parameter count "+count); |
| } |
| private static IndexOutOfBoundsException newIndexOutOfBoundsException(Object num) { |
| if (num instanceof Integer) num = "bad index: "+num; |
| return new IndexOutOfBoundsException(num.toString()); |
| } |
| |
| static final ConcurrentWeakInternSet<MethodType> internTable = new ConcurrentWeakInternSet<>(); |
| |
| static final Class<?>[] NO_PTYPES = {}; |
| |
| /** |
| * Finds or creates an instance of the given method type. |
| * @param rtype the return type |
| * @param ptypes the parameter types |
| * @return a method type with the given components |
| * @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null |
| * @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class} |
| */ |
| public static |
| MethodType methodType(Class<?> rtype, Class<?>[] ptypes) { |
| return makeImpl(rtype, ptypes, false); |
| } |
| |
| /** |
| * Finds or creates a method type with the given components. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param rtype the return type |
| * @param ptypes the parameter types |
| * @return a method type with the given components |
| * @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null |
| * @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class} |
| */ |
| public static |
| MethodType methodType(Class<?> rtype, List<Class<?>> ptypes) { |
| boolean notrust = false; // random List impl. could return evil ptypes array |
| return makeImpl(rtype, listToArray(ptypes), notrust); |
| } |
| |
| private static Class<?>[] listToArray(List<Class<?>> ptypes) { |
| // sanity check the size before the toArray call, since size might be huge |
| checkSlotCount(ptypes.size()); |
| return ptypes.toArray(NO_PTYPES); |
| } |
| |
| /** |
| * Finds or creates a method type with the given components. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * The leading parameter type is prepended to the remaining array. |
| * @param rtype the return type |
| * @param ptype0 the first parameter type |
| * @param ptypes the remaining parameter types |
| * @return a method type with the given components |
| * @throws NullPointerException if {@code rtype} or {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is null |
| * @throws IllegalArgumentException if {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is {@code void.class} |
| */ |
| public static |
| MethodType methodType(Class<?> rtype, Class<?> ptype0, Class<?>... ptypes) { |
| Class<?>[] ptypes1 = new Class<?>[1+ptypes.length]; |
| ptypes1[0] = ptype0; |
| System.arraycopy(ptypes, 0, ptypes1, 1, ptypes.length); |
| return makeImpl(rtype, ptypes1, true); |
| } |
| |
| /** |
| * Finds or creates a method type with the given components. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * The resulting method has no parameter types. |
| * @param rtype the return type |
| * @return a method type with the given return value |
| * @throws NullPointerException if {@code rtype} is null |
| */ |
| public static |
| MethodType methodType(Class<?> rtype) { |
| return makeImpl(rtype, NO_PTYPES, true); |
| } |
| |
| /** |
| * Finds or creates a method type with the given components. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * The resulting method has the single given parameter type. |
| * @param rtype the return type |
| * @param ptype0 the parameter type |
| * @return a method type with the given return value and parameter type |
| * @throws NullPointerException if {@code rtype} or {@code ptype0} is null |
| * @throws IllegalArgumentException if {@code ptype0} is {@code void.class} |
| */ |
| public static |
| MethodType methodType(Class<?> rtype, Class<?> ptype0) { |
| return makeImpl(rtype, new Class<?>[]{ ptype0 }, true); |
| } |
| |
| /** |
| * Finds or creates a method type with the given components. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * The resulting method has the same parameter types as {@code ptypes}, |
| * and the specified return type. |
| * @param rtype the return type |
| * @param ptypes the method type which supplies the parameter types |
| * @return a method type with the given components |
| * @throws NullPointerException if {@code rtype} or {@code ptypes} is null |
| */ |
| public static |
| MethodType methodType(Class<?> rtype, MethodType ptypes) { |
| return makeImpl(rtype, ptypes.ptypes, true); |
| } |
| |
| /** |
| * Sole factory method to find or create an interned method type. |
| * @param rtype desired return type |
| * @param ptypes desired parameter types |
| * @param trusted whether the ptypes can be used without cloning |
| * @return the unique method type of the desired structure |
| */ |
| /*trusted*/ static |
| MethodType makeImpl(Class<?> rtype, Class<?>[] ptypes, boolean trusted) { |
| MethodType mt = internTable.get(new MethodType(ptypes, rtype)); |
| if (mt != null) |
| return mt; |
| if (ptypes.length == 0) { |
| ptypes = NO_PTYPES; trusted = true; |
| } |
| mt = new MethodType(rtype, ptypes, trusted); |
| // promote the object to the Real Thing, and reprobe |
| mt.form = MethodTypeForm.findForm(mt); |
| return internTable.add(mt); |
| } |
| private static final MethodType[] objectOnlyTypes = new MethodType[20]; |
| |
| /** |
| * Finds or creates a method type whose components are {@code Object} with an optional trailing {@code Object[]} array. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * All parameters and the return type will be {@code Object}, |
| * except the final array parameter if any, which will be {@code Object[]}. |
| * @param objectArgCount number of parameters (excluding the final array parameter if any) |
| * @param finalArray whether there will be a trailing array parameter, of type {@code Object[]} |
| * @return a generally applicable method type, for all calls of the given fixed argument count and a collected array of further arguments |
| * @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255 (or 254, if {@code finalArray} is true) |
| * @see #genericMethodType(int) |
| */ |
| public static |
| MethodType genericMethodType(int objectArgCount, boolean finalArray) { |
| MethodType mt; |
| checkSlotCount(objectArgCount); |
| int ivarargs = (!finalArray ? 0 : 1); |
| int ootIndex = objectArgCount*2 + ivarargs; |
| if (ootIndex < objectOnlyTypes.length) { |
| mt = objectOnlyTypes[ootIndex]; |
| if (mt != null) return mt; |
| } |
| Class<?>[] ptypes = new Class<?>[objectArgCount + ivarargs]; |
| Arrays.fill(ptypes, Object.class); |
| if (ivarargs != 0) ptypes[objectArgCount] = Object[].class; |
| mt = makeImpl(Object.class, ptypes, true); |
| if (ootIndex < objectOnlyTypes.length) { |
| objectOnlyTypes[ootIndex] = mt; // cache it here also! |
| } |
| return mt; |
| } |
| |
| /** |
| * Finds or creates a method type whose components are all {@code Object}. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * All parameters and the return type will be Object. |
| * @param objectArgCount number of parameters |
| * @return a generally applicable method type, for all calls of the given argument count |
| * @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255 |
| * @see #genericMethodType(int, boolean) |
| */ |
| public static |
| MethodType genericMethodType(int objectArgCount) { |
| return genericMethodType(objectArgCount, false); |
| } |
| |
| /** |
| * Finds or creates a method type with a single different parameter type. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param num the index (zero-based) of the parameter type to change |
| * @param nptype a new parameter type to replace the old one with |
| * @return the same type, except with the selected parameter changed |
| * @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()} |
| * @throws IllegalArgumentException if {@code nptype} is {@code void.class} |
| * @throws NullPointerException if {@code nptype} is null |
| */ |
| public MethodType changeParameterType(int num, Class<?> nptype) { |
| if (parameterType(num) == nptype) return this; |
| checkPtype(nptype); |
| Class<?>[] nptypes = ptypes.clone(); |
| nptypes[num] = nptype; |
| return makeImpl(rtype, nptypes, true); |
| } |
| |
| /** |
| * Finds or creates a method type with additional parameter types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param num the position (zero-based) of the inserted parameter type(s) |
| * @param ptypesToInsert zero or more new parameter types to insert into the parameter list |
| * @return the same type, except with the selected parameter(s) inserted |
| * @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()} |
| * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} |
| * or if the resulting method type would have more than 255 parameter slots |
| * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null |
| */ |
| public MethodType insertParameterTypes(int num, Class<?>... ptypesToInsert) { |
| int len = ptypes.length; |
| if (num < 0 || num > len) |
| throw newIndexOutOfBoundsException(num); |
| int ins = checkPtypes(ptypesToInsert); |
| checkSlotCount(parameterSlotCount() + ptypesToInsert.length + ins); |
| int ilen = ptypesToInsert.length; |
| if (ilen == 0) return this; |
| Class<?>[] nptypes = Arrays.copyOfRange(ptypes, 0, len+ilen); |
| System.arraycopy(nptypes, num, nptypes, num+ilen, len-num); |
| System.arraycopy(ptypesToInsert, 0, nptypes, num, ilen); |
| return makeImpl(rtype, nptypes, true); |
| } |
| |
| /** |
| * Finds or creates a method type with additional parameter types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list |
| * @return the same type, except with the selected parameter(s) appended |
| * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} |
| * or if the resulting method type would have more than 255 parameter slots |
| * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null |
| */ |
| public MethodType appendParameterTypes(Class<?>... ptypesToInsert) { |
| return insertParameterTypes(parameterCount(), ptypesToInsert); |
| } |
| |
| /** |
| * Finds or creates a method type with additional parameter types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param num the position (zero-based) of the inserted parameter type(s) |
| * @param ptypesToInsert zero or more new parameter types to insert into the parameter list |
| * @return the same type, except with the selected parameter(s) inserted |
| * @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()} |
| * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} |
| * or if the resulting method type would have more than 255 parameter slots |
| * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null |
| */ |
| public MethodType insertParameterTypes(int num, List<Class<?>> ptypesToInsert) { |
| return insertParameterTypes(num, listToArray(ptypesToInsert)); |
| } |
| |
| /** |
| * Finds or creates a method type with additional parameter types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list |
| * @return the same type, except with the selected parameter(s) appended |
| * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} |
| * or if the resulting method type would have more than 255 parameter slots |
| * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null |
| */ |
| public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) { |
| return insertParameterTypes(parameterCount(), ptypesToInsert); |
| } |
| |
| /** |
| * Finds or creates a method type with modified parameter types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param start the position (zero-based) of the first replaced parameter type(s) |
| * @param end the position (zero-based) after the last replaced parameter type(s) |
| * @param ptypesToInsert zero or more new parameter types to insert into the parameter list |
| * @return the same type, except with the selected parameter(s) replaced |
| * @throws IndexOutOfBoundsException if {@code start} is negative or greater than {@code parameterCount()} |
| * or if {@code end} is negative or greater than {@code parameterCount()} |
| * or if {@code start} is greater than {@code end} |
| * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} |
| * or if the resulting method type would have more than 255 parameter slots |
| * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null |
| */ |
| /*non-public*/ MethodType replaceParameterTypes(int start, int end, Class<?>... ptypesToInsert) { |
| if (start == end) |
| return insertParameterTypes(start, ptypesToInsert); |
| int len = ptypes.length; |
| if (!(0 <= start && start <= end && end <= len)) |
| throw newIndexOutOfBoundsException("start="+start+" end="+end); |
| int ilen = ptypesToInsert.length; |
| if (ilen == 0) |
| return dropParameterTypes(start, end); |
| return dropParameterTypes(start, end).insertParameterTypes(start, ptypesToInsert); |
| } |
| |
| /** Replace the last arrayLength parameter types with the component type of arrayType. |
| * @param arrayType any array type |
| * @param arrayLength the number of parameter types to change |
| * @return the resulting type |
| */ |
| /*non-public*/ MethodType asSpreaderType(Class<?> arrayType, int arrayLength) { |
| assert(parameterCount() >= arrayLength); |
| int spreadPos = ptypes.length - arrayLength; |
| if (arrayLength == 0) return this; // nothing to change |
| if (arrayType == Object[].class) { |
| if (isGeneric()) return this; // nothing to change |
| if (spreadPos == 0) { |
| // no leading arguments to preserve; go generic |
| MethodType res = genericMethodType(arrayLength); |
| if (rtype != Object.class) { |
| res = res.changeReturnType(rtype); |
| } |
| return res; |
| } |
| } |
| Class<?> elemType = arrayType.getComponentType(); |
| assert(elemType != null); |
| for (int i = spreadPos; i < ptypes.length; i++) { |
| if (ptypes[i] != elemType) { |
| Class<?>[] fixedPtypes = ptypes.clone(); |
| Arrays.fill(fixedPtypes, i, ptypes.length, elemType); |
| return methodType(rtype, fixedPtypes); |
| } |
| } |
| return this; // arguments check out; no change |
| } |
| |
| /** Return the leading parameter type, which must exist and be a reference. |
| * @return the leading parameter type, after error checks |
| */ |
| /*non-public*/ Class<?> leadingReferenceParameter() { |
| Class<?> ptype; |
| if (ptypes.length == 0 || |
| (ptype = ptypes[0]).isPrimitive()) |
| throw newIllegalArgumentException("no leading reference parameter"); |
| return ptype; |
| } |
| |
| /** Delete the last parameter type and replace it with arrayLength copies of the component type of arrayType. |
| * @param arrayType any array type |
| * @param arrayLength the number of parameter types to insert |
| * @return the resulting type |
| */ |
| /*non-public*/ MethodType asCollectorType(Class<?> arrayType, int arrayLength) { |
| assert(parameterCount() >= 1); |
| assert(lastParameterType().isAssignableFrom(arrayType)); |
| MethodType res; |
| if (arrayType == Object[].class) { |
| res = genericMethodType(arrayLength); |
| if (rtype != Object.class) { |
| res = res.changeReturnType(rtype); |
| } |
| } else { |
| Class<?> elemType = arrayType.getComponentType(); |
| assert(elemType != null); |
| res = methodType(rtype, Collections.nCopies(arrayLength, elemType)); |
| } |
| if (ptypes.length == 1) { |
| return res; |
| } else { |
| return res.insertParameterTypes(0, parameterList().subList(0, ptypes.length-1)); |
| } |
| } |
| |
| /** |
| * Finds or creates a method type with some parameter types omitted. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param start the index (zero-based) of the first parameter type to remove |
| * @param end the index (greater than {@code start}) of the first parameter type after not to remove |
| * @return the same type, except with the selected parameter(s) removed |
| * @throws IndexOutOfBoundsException if {@code start} is negative or greater than {@code parameterCount()} |
| * or if {@code end} is negative or greater than {@code parameterCount()} |
| * or if {@code start} is greater than {@code end} |
| */ |
| public MethodType dropParameterTypes(int start, int end) { |
| int len = ptypes.length; |
| if (!(0 <= start && start <= end && end <= len)) |
| throw newIndexOutOfBoundsException("start="+start+" end="+end); |
| if (start == end) return this; |
| Class<?>[] nptypes; |
| if (start == 0) { |
| if (end == len) { |
| // drop all parameters |
| nptypes = NO_PTYPES; |
| } else { |
| // drop initial parameter(s) |
| nptypes = Arrays.copyOfRange(ptypes, end, len); |
| } |
| } else { |
| if (end == len) { |
| // drop trailing parameter(s) |
| nptypes = Arrays.copyOfRange(ptypes, 0, start); |
| } else { |
| int tail = len - end; |
| nptypes = Arrays.copyOfRange(ptypes, 0, start + tail); |
| System.arraycopy(ptypes, end, nptypes, start, tail); |
| } |
| } |
| return makeImpl(rtype, nptypes, true); |
| } |
| |
| /** |
| * Finds or creates a method type with a different return type. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * @param nrtype a return parameter type to replace the old one with |
| * @return the same type, except with the return type change |
| * @throws NullPointerException if {@code nrtype} is null |
| */ |
| public MethodType changeReturnType(Class<?> nrtype) { |
| if (returnType() == nrtype) return this; |
| return makeImpl(nrtype, ptypes, true); |
| } |
| |
| /** |
| * Reports if this type contains a primitive argument or return value. |
| * The return type {@code void} counts as a primitive. |
| * @return true if any of the types are primitives |
| */ |
| public boolean hasPrimitives() { |
| return form.hasPrimitives(); |
| } |
| |
| /** |
| * Reports if this type contains a wrapper argument or return value. |
| * Wrappers are types which box primitive values, such as {@link Integer}. |
| * The reference type {@code java.lang.Void} counts as a wrapper, |
| * if it occurs as a return type. |
| * @return true if any of the types are wrappers |
| */ |
| public boolean hasWrappers() { |
| return unwrap() != this; |
| } |
| |
| /** |
| * Erases all reference types to {@code Object}. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * All primitive types (including {@code void}) will remain unchanged. |
| * @return a version of the original type with all reference types replaced |
| */ |
| public MethodType erase() { |
| return form.erasedType(); |
| } |
| |
| /** |
| * Erases all reference types to {@code Object}, and all subword types to {@code int}. |
| * This is the reduced type polymorphism used by private methods |
| * such as {@link MethodHandle#invokeBasic invokeBasic}. |
| * @return a version of the original type with all reference and subword types replaced |
| */ |
| /*non-public*/ MethodType basicType() { |
| return form.basicType(); |
| } |
| |
| /** |
| * @return a version of the original type with MethodHandle prepended as the first argument |
| */ |
| /*non-public*/ MethodType invokerType() { |
| return insertParameterTypes(0, MethodHandle.class); |
| } |
| |
| /** |
| * Converts all types, both reference and primitive, to {@code Object}. |
| * Convenience method for {@link #genericMethodType(int) genericMethodType}. |
| * The expression {@code type.wrap().erase()} produces the same value |
| * as {@code type.generic()}. |
| * @return a version of the original type with all types replaced |
| */ |
| public MethodType generic() { |
| return genericMethodType(parameterCount()); |
| } |
| |
| /*non-public*/ boolean isGeneric() { |
| return this == erase() && !hasPrimitives(); |
| } |
| |
| /** |
| * Converts all primitive types to their corresponding wrapper types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * All reference types (including wrapper types) will remain unchanged. |
| * A {@code void} return type is changed to the type {@code java.lang.Void}. |
| * The expression {@code type.wrap().erase()} produces the same value |
| * as {@code type.generic()}. |
| * @return a version of the original type with all primitive types replaced |
| */ |
| public MethodType wrap() { |
| return hasPrimitives() ? wrapWithPrims(this) : this; |
| } |
| |
| /** |
| * Converts all wrapper types to their corresponding primitive types. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * All primitive types (including {@code void}) will remain unchanged. |
| * A return type of {@code java.lang.Void} is changed to {@code void}. |
| * @return a version of the original type with all wrapper types replaced |
| */ |
| public MethodType unwrap() { |
| MethodType noprims = !hasPrimitives() ? this : wrapWithPrims(this); |
| return unwrapWithNoPrims(noprims); |
| } |
| |
| private static MethodType wrapWithPrims(MethodType pt) { |
| assert(pt.hasPrimitives()); |
| MethodType wt = pt.wrapAlt; |
| if (wt == null) { |
| // fill in lazily |
| wt = MethodTypeForm.canonicalize(pt, MethodTypeForm.WRAP, MethodTypeForm.WRAP); |
| assert(wt != null); |
| pt.wrapAlt = wt; |
| } |
| return wt; |
| } |
| |
| private static MethodType unwrapWithNoPrims(MethodType wt) { |
| assert(!wt.hasPrimitives()); |
| MethodType uwt = wt.wrapAlt; |
| if (uwt == null) { |
| // fill in lazily |
| uwt = MethodTypeForm.canonicalize(wt, MethodTypeForm.UNWRAP, MethodTypeForm.UNWRAP); |
| if (uwt == null) |
| uwt = wt; // type has no wrappers or prims at all |
| wt.wrapAlt = uwt; |
| } |
| return uwt; |
| } |
| |
| /** |
| * Returns the parameter type at the specified index, within this method type. |
| * @param num the index (zero-based) of the desired parameter type |
| * @return the selected parameter type |
| * @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()} |
| */ |
| public Class<?> parameterType(int num) { |
| return ptypes[num]; |
| } |
| /** |
| * Returns the number of parameter types in this method type. |
| * @return the number of parameter types |
| */ |
| public int parameterCount() { |
| return ptypes.length; |
| } |
| /** |
| * Returns the return type of this method type. |
| * @return the return type |
| */ |
| public Class<?> returnType() { |
| return rtype; |
| } |
| |
| /** |
| * Presents the parameter types as a list (a convenience method). |
| * The list will be immutable. |
| * @return the parameter types (as an immutable list) |
| */ |
| public List<Class<?>> parameterList() { |
| return Collections.unmodifiableList(Arrays.asList(ptypes.clone())); |
| } |
| |
| /*non-public*/ Class<?> lastParameterType() { |
| int len = ptypes.length; |
| return len == 0 ? void.class : ptypes[len-1]; |
| } |
| |
| /** |
| * Presents the parameter types as an array (a convenience method). |
| * Changes to the array will not result in changes to the type. |
| * @return the parameter types (as a fresh copy if necessary) |
| */ |
| public Class<?>[] parameterArray() { |
| return ptypes.clone(); |
| } |
| |
| /** |
| * Compares the specified object with this type for equality. |
| * That is, it returns {@code true} if and only if the specified object |
| * is also a method type with exactly the same parameters and return type. |
| * @param x object to compare |
| * @see Object#equals(Object) |
| */ |
| @Override |
| public boolean equals(Object x) { |
| return this == x || x instanceof MethodType && equals((MethodType)x); |
| } |
| |
| private boolean equals(MethodType that) { |
| return this.rtype == that.rtype |
| && Arrays.equals(this.ptypes, that.ptypes); |
| } |
| |
| /** |
| * Returns the hash code value for this method type. |
| * It is defined to be the same as the hashcode of a List |
| * whose elements are the return type followed by the |
| * parameter types. |
| * @return the hash code value for this method type |
| * @see Object#hashCode() |
| * @see #equals(Object) |
| * @see List#hashCode() |
| */ |
| @Override |
| public int hashCode() { |
| int hashCode = 31 + rtype.hashCode(); |
| for (Class<?> ptype : ptypes) |
| hashCode = 31*hashCode + ptype.hashCode(); |
| return hashCode; |
| } |
| |
| /** |
| * Returns a string representation of the method type, |
| * of the form {@code "(PT0,PT1...)RT"}. |
| * The string representation of a method type is a |
| * parenthesis enclosed, comma separated list of type names, |
| * followed immediately by the return type. |
| * <p> |
| * Each type is represented by its |
| * {@link java.lang.Class#getSimpleName simple name}. |
| */ |
| @Override |
| public String toString() { |
| StringJoiner sj = new StringJoiner(",", "(", |
| ")" + rtype.getSimpleName()); |
| for (int i = 0; i < ptypes.length; i++) { |
| sj.add(ptypes[i].getSimpleName()); |
| } |
| return sj.toString(); |
| } |
| |
| /** True if the old return type can always be viewed (w/o casting) under new return type, |
| * and the new parameters can be viewed (w/o casting) under the old parameter types. |
| */ |
| /*non-public*/ |
| boolean isViewableAs(MethodType newType, boolean keepInterfaces) { |
| if (!VerifyType.isNullConversion(returnType(), newType.returnType(), keepInterfaces)) |
| return false; |
| return parametersAreViewableAs(newType, keepInterfaces); |
| } |
| /** True if the new parameters can be viewed (w/o casting) under the old parameter types. */ |
| /*non-public*/ |
| boolean parametersAreViewableAs(MethodType newType, boolean keepInterfaces) { |
| if (form == newType.form && form.erasedType == this) |
| return true; // my reference parameters are all Object |
| if (ptypes == newType.ptypes) |
| return true; |
| int argc = parameterCount(); |
| if (argc != newType.parameterCount()) |
| return false; |
| for (int i = 0; i < argc; i++) { |
| if (!VerifyType.isNullConversion(newType.parameterType(i), parameterType(i), keepInterfaces)) |
| return false; |
| } |
| return true; |
| } |
| /*non-public*/ |
| boolean isConvertibleTo(MethodType newType) { |
| MethodTypeForm oldForm = this.form(); |
| MethodTypeForm newForm = newType.form(); |
| if (oldForm == newForm) |
| // same parameter count, same primitive/object mix |
| return true; |
| if (!canConvert(returnType(), newType.returnType())) |
| return false; |
| Class<?>[] srcTypes = newType.ptypes; |
| Class<?>[] dstTypes = ptypes; |
| if (srcTypes == dstTypes) |
| return true; |
| int argc; |
| if ((argc = srcTypes.length) != dstTypes.length) |
| return false; |
| if (argc <= 1) { |
| if (argc == 1 && !canConvert(srcTypes[0], dstTypes[0])) |
| return false; |
| return true; |
| } |
| if ((oldForm.primitiveParameterCount() == 0 && oldForm.erasedType == this) || |
| (newForm.primitiveParameterCount() == 0 && newForm.erasedType == newType)) { |
| // Somewhat complicated test to avoid a loop of 2 or more trips. |
| // If either type has only Object parameters, we know we can convert. |
| assert(canConvertParameters(srcTypes, dstTypes)); |
| return true; |
| } |
| return canConvertParameters(srcTypes, dstTypes); |
| } |
| |
| /** Returns true if MHs.explicitCastArguments produces the same result as MH.asType. |
| * If the type conversion is impossible for either, the result should be false. |
| */ |
| /*non-public*/ |
| boolean explicitCastEquivalentToAsType(MethodType newType) { |
| if (this == newType) return true; |
| if (!explicitCastEquivalentToAsType(rtype, newType.rtype)) { |
| return false; |
| } |
| Class<?>[] srcTypes = newType.ptypes; |
| Class<?>[] dstTypes = ptypes; |
| if (dstTypes == srcTypes) { |
| return true; |
| } |
| assert(dstTypes.length == srcTypes.length); |
| for (int i = 0; i < dstTypes.length; i++) { |
| if (!explicitCastEquivalentToAsType(srcTypes[i], dstTypes[i])) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** Reports true if the src can be converted to the dst, by both asType and MHs.eCE, |
| * and with the same effect. |
| * MHs.eCA has the following "upgrades" to MH.asType: |
| * 1. interfaces are unchecked (that is, treated as if aliased to Object) |
| * Therefore, {@code Object->CharSequence} is possible in both cases but has different semantics |
| * 2. the full matrix of primitive-to-primitive conversions is supported |
| * Narrowing like {@code long->byte} and basic-typing like {@code boolean->int} |
| * are not supported by asType, but anything supported by asType is equivalent |
| * with MHs.eCE. |
| * 3a. unboxing conversions can be followed by the full matrix of primitive conversions |
| * 3b. unboxing of null is permitted (creates a zero primitive value) |
| * Other than interfaces, reference-to-reference conversions are the same. |
| * Boxing primitives to references is the same for both operators. |
| */ |
| private static boolean explicitCastEquivalentToAsType(Class<?> src, Class<?> dst) { |
| if (src == dst || dst == Object.class || dst == void.class) return true; |
| if (src.isPrimitive()) { |
| // Could be a prim/prim conversion, where casting is a strict superset. |
| // Or a boxing conversion, which is always to an exact wrapper class. |
| return canConvert(src, dst); |
| } else if (dst.isPrimitive()) { |
| // Unboxing behavior is different between MHs.eCA & MH.asType (see 3b). |
| return false; |
| } else { |
| // R->R always works, but we have to avoid a check-cast to an interface. |
| return !dst.isInterface() || dst.isAssignableFrom(src); |
| } |
| } |
| |
| private boolean canConvertParameters(Class<?>[] srcTypes, Class<?>[] dstTypes) { |
| for (int i = 0; i < srcTypes.length; i++) { |
| if (!canConvert(srcTypes[i], dstTypes[i])) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /*non-public*/ |
| static boolean canConvert(Class<?> src, Class<?> dst) { |
| // short-circuit a few cases: |
| if (src == dst || src == Object.class || dst == Object.class) return true; |
| // the remainder of this logic is documented in MethodHandle.asType |
| if (src.isPrimitive()) { |
| // can force void to an explicit null, a la reflect.Method.invoke |
| // can also force void to a primitive zero, by analogy |
| if (src == void.class) return true; //or !dst.isPrimitive()? |
| Wrapper sw = Wrapper.forPrimitiveType(src); |
| if (dst.isPrimitive()) { |
| // P->P must widen |
| return Wrapper.forPrimitiveType(dst).isConvertibleFrom(sw); |
| } else { |
| // P->R must box and widen |
| return dst.isAssignableFrom(sw.wrapperType()); |
| } |
| } else if (dst.isPrimitive()) { |
| // any value can be dropped |
| if (dst == void.class) return true; |
| Wrapper dw = Wrapper.forPrimitiveType(dst); |
| // R->P must be able to unbox (from a dynamically chosen type) and widen |
| // For example: |
| // Byte/Number/Comparable/Object -> dw:Byte -> byte. |
| // Character/Comparable/Object -> dw:Character -> char |
| // Boolean/Comparable/Object -> dw:Boolean -> boolean |
| // This means that dw must be cast-compatible with src. |
| if (src.isAssignableFrom(dw.wrapperType())) { |
| return true; |
| } |
| // The above does not work if the source reference is strongly typed |
| // to a wrapper whose primitive must be widened. For example: |
| // Byte -> unbox:byte -> short/int/long/float/double |
| // Character -> unbox:char -> int/long/float/double |
| if (Wrapper.isWrapperType(src) && |
| dw.isConvertibleFrom(Wrapper.forWrapperType(src))) { |
| // can unbox from src and then widen to dst |
| return true; |
| } |
| // We have already covered cases which arise due to runtime unboxing |
| // of a reference type which covers several wrapper types: |
| // Object -> cast:Integer -> unbox:int -> long/float/double |
| // Serializable -> cast:Byte -> unbox:byte -> byte/short/int/long/float/double |
| // An marginal case is Number -> dw:Character -> char, which would be OK if there were a |
| // subclass of Number which wraps a value that can convert to char. |
| // Since there is none, we don't need an extra check here to cover char or boolean. |
| return false; |
| } else { |
| // R->R always works, since null is always valid dynamically |
| return true; |
| } |
| } |
| |
| /// Queries which have to do with the bytecode architecture |
| |
| /** Reports the number of JVM stack slots required to invoke a method |
| * of this type. Note that (for historical reasons) the JVM requires |
| * a second stack slot to pass long and double arguments. |
| * So this method returns {@link #parameterCount() parameterCount} plus the |
| * number of long and double parameters (if any). |
| * <p> |
| * This method is included for the benefit of applications that must |
| * generate bytecodes that process method handles and invokedynamic. |
| * @return the number of JVM stack slots for this type's parameters |
| */ |
| /*non-public*/ int parameterSlotCount() { |
| return form.parameterSlotCount(); |
| } |
| |
| /*non-public*/ Invokers invokers() { |
| Invokers inv = invokers; |
| if (inv != null) return inv; |
| invokers = inv = new Invokers(this); |
| return inv; |
| } |
| |
| /** Reports the number of JVM stack slots which carry all parameters including and after |
| * the given position, which must be in the range of 0 to |
| * {@code parameterCount} inclusive. Successive parameters are |
| * more shallowly stacked, and parameters are indexed in the bytecodes |
| * according to their trailing edge. Thus, to obtain the depth |
| * in the outgoing call stack of parameter {@code N}, obtain |
| * the {@code parameterSlotDepth} of its trailing edge |
| * at position {@code N+1}. |
| * <p> |
| * Parameters of type {@code long} and {@code double} occupy |
| * two stack slots (for historical reasons) and all others occupy one. |
| * Therefore, the number returned is the number of arguments |
| * <em>including</em> and <em>after</em> the given parameter, |
| * <em>plus</em> the number of long or double arguments |
| * at or after the argument for the given parameter. |
| * <p> |
| * This method is included for the benefit of applications that must |
| * generate bytecodes that process method handles and invokedynamic. |
| * @param num an index (zero-based, inclusive) within the parameter types |
| * @return the index of the (shallowest) JVM stack slot transmitting the |
| * given parameter |
| * @throws IllegalArgumentException if {@code num} is negative or greater than {@code parameterCount()} |
| */ |
| /*non-public*/ int parameterSlotDepth(int num) { |
| if (num < 0 || num > ptypes.length) |
| parameterType(num); // force a range check |
| return form.parameterToArgSlot(num-1); |
| } |
| |
| /** Reports the number of JVM stack slots required to receive a return value |
| * from a method of this type. |
| * If the {@link #returnType() return type} is void, it will be zero, |
| * else if the return type is long or double, it will be two, else one. |
| * <p> |
| * This method is included for the benefit of applications that must |
| * generate bytecodes that process method handles and invokedynamic. |
| * @return the number of JVM stack slots (0, 1, or 2) for this type's return value |
| * Will be removed for PFD. |
| */ |
| /*non-public*/ int returnSlotCount() { |
| return form.returnSlotCount(); |
| } |
| |
| /** |
| * Finds or creates an instance of a method type, given the spelling of its bytecode descriptor. |
| * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. |
| * Any class or interface name embedded in the descriptor string |
| * will be resolved by calling {@link ClassLoader#loadClass(java.lang.String)} |
| * on the given loader (or if it is null, on the system class loader). |
| * <p> |
| * Note that it is possible to encounter method types which cannot be |
| * constructed by this method, because their component types are |
| * not all reachable from a common class loader. |
| * <p> |
| * This method is included for the benefit of applications that must |
| * generate bytecodes that process method handles and {@code invokedynamic}. |
| * @param descriptor a bytecode-level type descriptor string "(T...)T" |
| * @param loader the class loader in which to look up the types |
| * @return a method type matching the bytecode-level type descriptor |
| * @throws NullPointerException if the string is null |
| * @throws IllegalArgumentException if the string is not well-formed |
| * @throws TypeNotPresentException if a named type cannot be found |
| */ |
| public static MethodType fromMethodDescriptorString(String descriptor, ClassLoader loader) |
| throws IllegalArgumentException, TypeNotPresentException |
| { |
| return fromDescriptor(descriptor, |
| (loader == null) ? ClassLoader.getSystemClassLoader() : loader); |
| } |
| |
| /** |
| * Same as {@link #fromMethodDescriptorString(String, ClassLoader)}, but |
| * {@code null} ClassLoader means the bootstrap loader is used here. |
| * <p> |
| * IMPORTANT: This method is preferable for JDK internal use as it more |
| * correctly interprets {@code null} ClassLoader than |
| * {@link #fromMethodDescriptorString(String, ClassLoader)}. |
| * Use of this method also avoids early initialization issues when system |
| * ClassLoader is not initialized yet. |
| */ |
| static MethodType fromDescriptor(String descriptor, ClassLoader loader) |
| throws IllegalArgumentException, TypeNotPresentException |
| { |
| if (!descriptor.startsWith("(") || // also generates NPE if needed |
| descriptor.indexOf(')') < 0 || |
| descriptor.indexOf('.') >= 0) |
| throw newIllegalArgumentException("not a method descriptor: "+descriptor); |
| List<Class<?>> types = BytecodeDescriptor.parseMethod(descriptor, loader); |
| Class<?> rtype = types.remove(types.size() - 1); |
| checkSlotCount(types.size()); |
| Class<?>[] ptypes = listToArray(types); |
| return makeImpl(rtype, ptypes, true); |
| } |
| |
| /** |
| * Produces a bytecode descriptor representation of the method type. |
| * <p> |
| * Note that this is not a strict inverse of {@link #fromMethodDescriptorString fromMethodDescriptorString}. |
| * Two distinct classes which share a common name but have different class loaders |
| * will appear identical when viewed within descriptor strings. |
| * <p> |
| * This method is included for the benefit of applications that must |
| * generate bytecodes that process method handles and {@code invokedynamic}. |
| * {@link #fromMethodDescriptorString(java.lang.String, java.lang.ClassLoader) fromMethodDescriptorString}, |
| * because the latter requires a suitable class loader argument. |
| * @return the bytecode type descriptor representation |
| */ |
| public String toMethodDescriptorString() { |
| String desc = methodDescriptor; |
| if (desc == null) { |
| desc = BytecodeDescriptor.unparse(this); |
| methodDescriptor = desc; |
| } |
| return desc; |
| } |
| |
| /*non-public*/ static String toFieldDescriptorString(Class<?> cls) { |
| return BytecodeDescriptor.unparse(cls); |
| } |
| |
| /// Serialization. |
| |
| /** |
| * There are no serializable fields for {@code MethodType}. |
| */ |
| private static final java.io.ObjectStreamField[] serialPersistentFields = { }; |
| |
| /** |
| * Save the {@code MethodType} instance to a stream. |
| * |
| * @serialData |
| * For portability, the serialized format does not refer to named fields. |
| * Instead, the return type and parameter type arrays are written directly |
| * from the {@code writeObject} method, using two calls to {@code s.writeObject} |
| * as follows: |
| * <blockquote><pre>{@code |
| s.writeObject(this.returnType()); |
| s.writeObject(this.parameterArray()); |
| * }</pre></blockquote> |
| * <p> |
| * The deserialized field values are checked as if they were |
| * provided to the factory method {@link #methodType(Class,Class[]) methodType}. |
| * For example, null values, or {@code void} parameter types, |
| * will lead to exceptions during deserialization. |
| * @param s the stream to write the object to |
| * @throws java.io.IOException if there is a problem writing the object |
| */ |
| private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException { |
| s.defaultWriteObject(); // requires serialPersistentFields to be an empty array |
| s.writeObject(returnType()); |
| s.writeObject(parameterArray()); |
| } |
| |
| /** |
| * Reconstitute the {@code MethodType} instance from a stream (that is, |
| * deserialize it). |
| * This instance is a scratch object with bogus final fields. |
| * It provides the parameters to the factory method called by |
| * {@link #readResolve readResolve}. |
| * After that call it is discarded. |
| * @param s the stream to read the object from |
| * @throws java.io.IOException if there is a problem reading the object |
| * @throws ClassNotFoundException if one of the component classes cannot be resolved |
| * @see #MethodType() |
| * @see #readResolve |
| * @see #writeObject |
| */ |
| private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException { |
| s.defaultReadObject(); // requires serialPersistentFields to be an empty array |
| |
| Class<?> returnType = (Class<?>) s.readObject(); |
| Class<?>[] parameterArray = (Class<?>[]) s.readObject(); |
| |
| // Probably this object will never escape, but let's check |
| // the field values now, just to be sure. |
| checkRtype(returnType); |
| checkPtypes(parameterArray); |
| |
| parameterArray = parameterArray.clone(); // make sure it is unshared |
| MethodType_init(returnType, parameterArray); |
| } |
| |
| /** |
| * For serialization only. |
| * Sets the final fields to null, pending {@code Unsafe.putObject}. |
| */ |
| private MethodType() { |
| this.rtype = null; |
| this.ptypes = null; |
| } |
| private void MethodType_init(Class<?> rtype, Class<?>[] ptypes) { |
| // In order to communicate these values to readResolve, we must |
| // store them into the implementation-specific final fields. |
| checkRtype(rtype); |
| checkPtypes(ptypes); |
| UNSAFE.putObject(this, OffsetHolder.rtypeOffset, rtype); |
| UNSAFE.putObject(this, OffsetHolder.ptypesOffset, ptypes); |
| } |
| |
| // Support for resetting final fields while deserializing. Implement Holder |
| // pattern to make the rarely needed offset calculation lazy. |
| private static class OffsetHolder { |
| private static final long rtypeOffset, ptypesOffset; |
| static { |
| try { |
| rtypeOffset = UNSAFE.objectFieldOffset |
| (MethodType.class.getDeclaredField("rtype")); |
| ptypesOffset = UNSAFE.objectFieldOffset |
| (MethodType.class.getDeclaredField("ptypes")); |
| } catch (Exception ex) { |
| throw new Error(ex); |
| } |
| } |
| } |
| |
| /** |
| * Resolves and initializes a {@code MethodType} object |
| * after serialization. |
| * @return the fully initialized {@code MethodType} object |
| */ |
| private Object readResolve() { |
| // Do not use a trusted path for deserialization: |
| //return makeImpl(rtype, ptypes, true); |
| // Verify all operands, and make sure ptypes is unshared: |
| return methodType(rtype, ptypes); |
| } |
| |
| /** |
| * Simple implementation of weak concurrent intern set. |
| * |
| * @param <T> interned type |
| */ |
| private static class ConcurrentWeakInternSet<T> { |
| |
| private final ConcurrentMap<WeakEntry<T>, WeakEntry<T>> map; |
| private final ReferenceQueue<T> stale; |
| |
| public ConcurrentWeakInternSet() { |
| this.map = new ConcurrentHashMap<>(); |
| this.stale = new ReferenceQueue<>(); |
| } |
| |
| /** |
| * Get the existing interned element. |
| * This method returns null if no element is interned. |
| * |
| * @param elem element to look up |
| * @return the interned element |
| */ |
| public T get(T elem) { |
| if (elem == null) throw new NullPointerException(); |
| expungeStaleElements(); |
| |
| WeakEntry<T> value = map.get(new WeakEntry<>(elem)); |
| if (value != null) { |
| T res = value.get(); |
| if (res != null) { |
| return res; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Interns the element. |
| * Always returns non-null element, matching the one in the intern set. |
| * Under the race against another add(), it can return <i>different</i> |
| * element, if another thread beats us to interning it. |
| * |
| * @param elem element to add |
| * @return element that was actually added |
| */ |
| public T add(T elem) { |
| if (elem == null) throw new NullPointerException(); |
| |
| // Playing double race here, and so spinloop is required. |
| // First race is with two concurrent updaters. |
| // Second race is with GC purging weak ref under our feet. |
| // Hopefully, we almost always end up with a single pass. |
| T interned; |
| WeakEntry<T> e = new WeakEntry<>(elem, stale); |
| do { |
| expungeStaleElements(); |
| WeakEntry<T> exist = map.putIfAbsent(e, e); |
| interned = (exist == null) ? elem : exist.get(); |
| } while (interned == null); |
| return interned; |
| } |
| |
| private void expungeStaleElements() { |
| Reference<? extends T> reference; |
| while ((reference = stale.poll()) != null) { |
| map.remove(reference); |
| } |
| } |
| |
| private static class WeakEntry<T> extends WeakReference<T> { |
| |
| public final int hashcode; |
| |
| public WeakEntry(T key, ReferenceQueue<T> queue) { |
| super(key, queue); |
| hashcode = key.hashCode(); |
| } |
| |
| public WeakEntry(T key) { |
| super(key); |
| hashcode = key.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (obj instanceof WeakEntry) { |
| Object that = ((WeakEntry) obj).get(); |
| Object mine = get(); |
| return (that == null || mine == null) ? (this == obj) : mine.equals(that); |
| } |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| return hashcode; |
| } |
| |
| } |
| } |
| |
| } |