6839872: remove implementation inheritance from JSR 292 APIs
Summary: move everything into a single package; remove all multi-package machinery
Reviewed-by: twisti, forax
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* published by the Free Software Foundation. Oracle designates this
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*
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* 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).
*
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*
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package java.dyn;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import sun.dyn.util.BytecodeDescriptor;
import static java.dyn.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 = {};
/**
* Find or create 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;
}
/**
* Convert 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 historic 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();
}
/**
* Find or create 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);
}
}