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 * 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

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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.Access;

import sun.dyn.Invokers;

import sun.dyn.MethodTypeImpl;

import sun.dyn.util.BytecodeDescriptor;

import static sun.dyn.MemberName.newIllegalArgumentException;

/**

 * 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

 * 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

 * 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 {

    private final Class<?>   rtype;

    private final Class<?>[] ptypes;

    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

    private static final Access IMPL_TOKEN = Access.getToken();

    // share a cache with a friend in this package

    Invokers getInvokers() { return invokers; }

    void setInvokers(Invokers inv) { invokers = inv; }

    static {

        // This hack allows the implementation package special access to

        // the internals of MethodType.  In particular, the MTImpl has all sorts

        // of cached information useful to the implementation code.

        MethodTypeImpl.setMethodTypeFriend(IMPL_TOKEN, new MethodTypeImpl.MethodTypeFriend() {

            public Class<?>[] ptypes(MethodType mt)        { return mt.ptypes; }

            public MethodTypeImpl form(MethodType mt)      { return mt.form; }

            public void setForm(MethodType mt, MethodTypeImpl form) {

                assert(mt.form == null);

                mt.form = (MethodTypeForm) form;

            }

            public MethodType makeImpl(Class<?> rtype, Class<?>[] ptypes, boolean trusted) {

                return MethodType.makeImpl(rtype, ptypes, trusted);

            }

            public MethodTypeImpl newMethodTypeForm(MethodType mt) {

                return new MethodTypeForm(mt);

            }

            public Invokers getInvokers(MethodType mt)    { return mt.invokers; }

            public void setInvokers(MethodType mt, Invokers inv) { mt.invokers = inv; }

        });

    }

    private MethodType(Class<?> rtype, Class<?>[] ptypes) {

        checkRtype(rtype);

        checkPtypes(ptypes);

        this.rtype = rtype;

        this.ptypes = ptypes;

    }

        rtype.equals(rtype);  // null check

    }

        for (Class<?> ptype : ptypes) {

        }

    }

    static final HashMap<MethodType,MethodType> internTable

            = new HashMap<MethodType, MethodType>();

    static final Class<?>[] NO_PTYPES = {};

     * @param rtype  the return type

     * @param ptypes the parameter types

     */

    public static

    MethodType methodType(Class<?> rtype, Class<?>[] ptypes) {

        return makeImpl(rtype, ptypes, false);

    }

    public static

        boolean notrust = false;  // random List impl. could return evil ptypes array

        return makeImpl(rtype, ptypes.toArray(NO_PTYPES), notrust);

    }

     */

    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);

    }

     */

    public static

    MethodType methodType(Class<?> rtype) {

        return makeImpl(rtype, NO_PTYPES, true);

    }

     */

    public static

    MethodType methodType(Class<?> rtype, Class<?> ptype0) {

        return makeImpl(rtype, new Class<?>[]{ ptype0 }, true);

    }

     */

    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

     */

    private 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

        MethodTypeImpl.initForm(IMPL_TOKEN, mt1);

        synchronized (internTable) {

            mt0 = internTable.get(mt1);

            if (mt0 != null)

                return mt0;

            internTable.put(mt1, mt1);

        }

        return mt1;

    }

    // Entry point from JVM.  TODO: Change the name & signature.

    private static MethodType makeImpl(Class<?> rtype, Class<?>[] ptypes,

            boolean ignore1, boolean ignore2) {

        return makeImpl(rtype, ptypes, true);

    }

    private static final MethodType[] objectOnlyTypes = new MethodType[20];

    /**

     * 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

     * @see #genericMethodType(int)

     */

    public static

    MethodType genericMethodType(int objectArgCount, boolean varargs) {

        MethodType mt;

        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;

    }

    /**

     * 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

     * @see #genericMethodType(int, boolean)

     */

    public static

    MethodType genericMethodType(int objectArgCount) {

        return genericMethodType(objectArgCount, false);

    }

     * @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

     */

    public MethodType changeParameterType(int num, Class<?> nptype) {

        if (parameterType(num) == nptype)  return this;

        Class<?>[] nptypes = ptypes.clone();

        nptypes[num] = nptype;

        return makeImpl(rtype, nptypes, true);

    }

     * @param num    the position (zero-based) of the inserted parameter type(s)

     * @return the same type, except with the selected parameter(s) inserted

     */

    public MethodType insertParameterTypes(int num, Class<?>... ptypesToInsert) {

        int len = ptypes.length;

        if (num < 0 || num > len)

        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);

    }

     * @return the same type, except with the selected parameter(s) appended

     */

    public MethodType appendParameterTypes(Class<?>... ptypesToInsert) {

        return insertParameterTypes(parameterCount(), ptypesToInsert);

    }

     * @return the same type, except with the selected parameter(s) appended

     */

    public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) {

        return insertParameterTypes(parameterCount(), ptypesToInsert);

    }

     * @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

     */

    public MethodType dropParameterTypes(int start, int end) {

        int len = ptypes.length;

        if (!(0 <= start && start <= end && end <= len))

        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);

    }

     * @param nrtype a return parameter type to replace the old one with

     * @return the same type, except with the return type change

     */

    public MethodType changeReturnType(Class<?> nrtype) {

        if (returnType() == nrtype)  return this;

        return makeImpl(nrtype, ptypes, true);

    }

     * The return type {@code void} counts as a primitive.

     * @return true if any of the types are primitives

     */

    public boolean hasPrimitives() {

        return form.hasPrimitives();

    }

     * 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;

    }

     * 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();

    }

     * 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());

    }