--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/lang/invoke/MethodType.java Wed Mar 23 23:02:31 2011 -0700
@@ -0,0 +1,841 @@
+/*
+ * Copyright (c) 2008, 2011, 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 java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import sun.invoke.util.BytecodeDescriptor;
+import static java.lang.invoke.MethodHandleStatics.*;
+
+/**
+ * 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#invokeGeneric MethodHandle.invokeGeneric}, 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 more details, see the <a href="package-summary.html#mtcon">package summary</a>.
+ * <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 MethodTypeForm form; // erased form, plus cached data about primitives
+ private MethodType wrapAlt; // alternative wrapped/unwrapped version
+ private Invokers invokers; // cache of handy higher-order adapters
+
+ /**
+ * Check the given parameters for validity and store them into the final fields.
+ */
+ private MethodType(Class<?> rtype, Class<?>[] ptypes) {
+ checkRtype(rtype);
+ checkPtypes(ptypes);
+ this.rtype = rtype;
+ this.ptypes = ptypes;
+ }
+
+ /*trusted*/ MethodTypeForm form() { return form; }
+ /*trusted*/ Class<?> rtype() { return rtype; }
+ /*trusted*/ Class<?>[] ptypes() { return ptypes; }
+
+ private static void checkRtype(Class<?> rtype) {
+ rtype.equals(rtype); // null check
+ }
+ private static int checkPtype(Class<?> ptype) {
+ ptype.getClass(); //NPE
+ if (ptype == void.class)
+ throw newIllegalArgumentException("parameter type cannot be void");
+ if (ptype == double.class || ptype == long.class) return 1;
+ return 0;
+ }
+ /** Return number of extra slots (count of long/double args). */
+ private static int checkPtypes(Class<?>[] ptypes) {
+ int slots = 0;
+ for (Class<?> ptype : ptypes) {
+ slots += checkPtype(ptype);
+ }
+ checkSlotCount(ptypes.length + slots);
+ return slots;
+ }
+ private static void checkSlotCount(int count) {
+ if ((count & 0xFF) != 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 HashMap<MethodType,MethodType> internTable
+ = new HashMap<MethodType, MethodType>();
+
+ 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}.
+ * @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, ptypes.toArray(NO_PTYPES), notrust);
+ }
+
+ /**
+ * 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.
+ * @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.
+ * @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.
+ * @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.
+ * @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) {
+ if (ptypes == null || ptypes.length == 0) {
+ ptypes = NO_PTYPES; trusted = true;
+ }
+ MethodType mt1 = new MethodType(rtype, ptypes);
+ MethodType mt0;
+ synchronized (internTable) {
+ mt0 = internTable.get(mt1);
+ if (mt0 != null)
+ return mt0;
+ }
+ if (!trusted)
+ // defensively copy the array passed in by the user
+ mt1 = new MethodType(rtype, ptypes.clone());
+ // promote the object to the Real Thing, and reprobe
+ MethodTypeForm form = MethodTypeForm.findForm(mt1);
+ mt1.form = form;
+ if (form.erasedType == mt1) {
+ // This is a principal (erased) type; show it to the JVM.
+ MethodHandleNatives.init(mt1);
+ }
+ synchronized (internTable) {
+ mt0 = internTable.get(mt1);
+ if (mt0 != null)
+ return mt0;
+ internTable.put(mt1, mt1);
+ }
+ return mt1;
+ }
+
+ 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 varargs parameter if any, which will be {@code Object[]}.
+ * @param objectArgCount number of parameters (excluding the varargs parameter if any)
+ * @param varargs whether there will be a varargs parameter, of type {@code Object[]}
+ * @return a totally generic method type, given only its count of parameters and varargs
+ * @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255
+ * @see #genericMethodType(int)
+ */
+ public static
+ MethodType genericMethodType(int objectArgCount, boolean varargs) {
+ MethodType mt;
+ checkSlotCount(objectArgCount);
+ int ivarargs = (!varargs ? 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 totally generic method type, given only its count of parameters
+ * @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, ptypesToInsert.toArray(NO_PTYPES));
+ }
+
+ /**
+ * 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 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.
+ * @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();
+ }
+
+ /**
+ * 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());
+ }
+
+ /**
+ * 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));
+ }
+
+ /**
+ * 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 <tt>true</tt> 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() {
+ StringBuilder sb = new StringBuilder();
+ sb.append("(");
+ for (int i = 0; i < ptypes.length; i++) {
+ if (i > 0) sb.append(",");
+ sb.append(ptypes[i].getSimpleName());
+ }
+ sb.append(")");
+ sb.append(rtype.getSimpleName());
+ return sb.toString();
+ }
+
+ /// 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 benfit 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 after the argument for the given parameter.
+ * <p>
+ * This method is included for the benfit 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 benfit 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 benfit 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 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
+ {
+ List<Class<?>> types = BytecodeDescriptor.parseMethod(descriptor, loader);
+ Class<?> rtype = types.remove(types.size() - 1);
+ Class<?>[] ptypes = types.toArray(NO_PTYPES);
+ 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 benfit 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() {
+ return BytecodeDescriptor.unparse(this);
+ }
+
+ /// 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>
+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 the stream to write the object to
+ */
+ 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 the stream to read the object from
+ * @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, rtypeOffset, rtype);
+ unsafe.putObject(this, ptypesOffset, ptypes);
+ }
+
+ // Support for resetting final fields while deserializing
+ private static final sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
+ 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);
+ }
+}