https://openjdk.java.net/ 
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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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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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 *
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package com.sun.tools.jdi;

import com.sun.jdi.ClassNotLoadedException;
import com.sun.jdi.ClassType;
import com.sun.jdi.IncompatibleThreadStateException;
import com.sun.jdi.InterfaceType;
import com.sun.jdi.InvalidTypeException;
import com.sun.jdi.InvocationException;
import com.sun.jdi.Method;
import com.sun.jdi.ReferenceType;
import com.sun.jdi.ThreadReference;
import com.sun.jdi.Value;
import com.sun.jdi.VirtualMachine;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;


A supertype for ReferenceTypes allowing method invocations

/**
 * A supertype for ReferenceTypes allowing method invocations
 */
abstract class InvokableTypeImpl extends ReferenceTypeImpl {
    
The invocation result wrapper
It is necessary because both ClassType and InterfaceType
use their own type to represent the invocation result

/**
     * The invocation result wrapper
     * It is necessary because both ClassType and InterfaceType
     * use their own type to represent the invocation result
     */
    static interface InvocationResult {
        ObjectReferenceImpl getException();
        ValueImpl getResult();
    }

    InvokableTypeImpl(VirtualMachine aVm, long aRef) {
        super(aVm, aRef);
    }

    
Method invocation support.
Shared by ClassType and InterfaceType

Params:
  • threadIntf – the thread in which to invoke.
  • methodIntf – method the Method to invoke.
  • origArguments – the list of Value arguments bound to the invoked method. Values from the list are assigned to arguments in the order they appear in the method signature.
  • options – the integer bit flag options.
Throws:
  • IllegalArgumentException – if the method is not
a member of this type, if the size of the argument list
does not match the number of declared arguments for the method, or
if the method is not static or is a static initializer.
  •  {@link InvalidTypeException} if any argument in the
 – argument list is not assignable to the corresponding method argument
type.
  • ClassNotLoadedException – if any argument type has not yet been loaded
through the appropriate class loader.
  • IncompatibleThreadStateException – if the specified thread has not
been suspended by an event.
  • InvocationException – if the method invocation resulted in
an exception in the target VM.
  • InvalidTypeException – If the arguments do not meet this requirement --
        Object arguments must be assignment compatible with the argument
        type.  This implies that the argument type must be
        loaded through the enclosing class's class loader.
        Primitive arguments must be either assignment compatible with the
        argument type or must be convertible to the argument type without loss
        of information. See JLS section 5.2 for more information on assignment
        compatibility.
  • VMCannotBeModifiedException – if the VirtualMachine is read-only - see VirtualMachine.canBeModified().
Returns:a Value mirror of the invoked method's return value.
/**
     * Method invocation support.
     * Shared by ClassType and InterfaceType
     * @param threadIntf the thread in which to invoke.
     * @param methodIntf method the {@link Method} to invoke.
     * @param origArguments the list of {@link Value} arguments bound to the
     * invoked method. Values from the list are assigned to arguments
     * in the order they appear in the method signature.
     * @param options the integer bit flag options.
     * @return a {@link Value} mirror of the invoked method's return value.
     * @throws java.lang.IllegalArgumentException if the method is not
     * a member of this type, if the size of the argument list
     * does not match the number of declared arguments for the method, or
     * if the method is not static or is a static initializer.
     * @throws {@link InvalidTypeException} if any argument in the
     * argument list is not assignable to the corresponding method argument
     * type.
     * @throws ClassNotLoadedException if any argument type has not yet been loaded
     * through the appropriate class loader.
     * @throws IncompatibleThreadStateException if the specified thread has not
     * been suspended by an event.
     * @throws InvocationException if the method invocation resulted in
     * an exception in the target VM.
     * @throws InvalidTypeException If the arguments do not meet this requirement --
     *         Object arguments must be assignment compatible with the argument
     *         type.  This implies that the argument type must be
     *         loaded through the enclosing class's class loader.
     *         Primitive arguments must be either assignment compatible with the
     *         argument type or must be convertible to the argument type without loss
     *         of information. See JLS section 5.2 for more information on assignment
     *         compatibility.
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     */
    final public Value invokeMethod(ThreadReference threadIntf, Method methodIntf,
                                    List<? extends Value> origArguments, int options)
                                        throws InvalidTypeException,
                                               ClassNotLoadedException,
                                               IncompatibleThreadStateException,
                                               InvocationException {
        validateMirror(threadIntf);
        validateMirror(methodIntf);
        validateMirrorsOrNulls(origArguments);
        MethodImpl method = (MethodImpl) methodIntf;
        ThreadReferenceImpl thread = (ThreadReferenceImpl) threadIntf;
        validateMethodInvocation(method);
        List<? extends Value> arguments = method.validateAndPrepareArgumentsForInvoke(origArguments);
        ValueImpl[] args = arguments.toArray(new ValueImpl[0]);
        InvocationResult ret;
        try {
            PacketStream stream = sendInvokeCommand(thread, method, args, options);
            ret = waitForReply(stream);
        } catch (JDWPException exc) {
            if (exc.errorCode() == JDWP.Error.INVALID_THREAD) {
                throw new IncompatibleThreadStateException();
            } else {
                throw exc.toJDIException();
            }
        }
        /*
         * There is an implict VM-wide suspend at the conclusion
         * of a normal (non-single-threaded) method invoke
         */
        if ((options & ClassType.INVOKE_SINGLE_THREADED) == 0) {
            vm.notifySuspend();
        }
        if (ret.getException() != null) {
            throw new InvocationException(ret.getException());
        } else {
            return ret.getResult();
        }
    }

    @Override
    boolean isAssignableTo(ReferenceType type) {
        ClassTypeImpl superclazz = (ClassTypeImpl) superclass();
        if (this.equals(type)) {
            return true;
        } else if ((superclazz != null) && superclazz.isAssignableTo(type)) {
            return true;
        } else {
            List<InterfaceType> interfaces = interfaces();
            Iterator<InterfaceType> iter = interfaces.iterator();
            while (iter.hasNext()) {
                InterfaceTypeImpl interfaze = (InterfaceTypeImpl) iter.next();
                if (interfaze.isAssignableTo(type)) {
                    return true;
                }
            }
            return false;
        }
    }

    @Override
    final void addVisibleMethods(Map<String, Method> methodMap, Set<InterfaceType> seenInterfaces) {
        /*
         * Add methods from
         * parent types first, so that the methods in this class will
         * overwrite them in the hash table
         */
        Iterator<InterfaceType> iter = interfaces().iterator();
        while (iter.hasNext()) {
            InterfaceTypeImpl interfaze = (InterfaceTypeImpl) iter.next();
            if (!seenInterfaces.contains(interfaze)) {
                interfaze.addVisibleMethods(methodMap, seenInterfaces);
                seenInterfaces.add(interfaze);
            }
        }
        ClassTypeImpl clazz = (ClassTypeImpl) superclass();
        if (clazz != null) {
            clazz.addVisibleMethods(methodMap, seenInterfaces);
        }
        addToMethodMap(methodMap, methods());
    }

    final void addInterfaces(List<InterfaceType> list) {
        List<InterfaceType> immediate = interfaces();
        list.addAll(interfaces());
        Iterator<InterfaceType> iter = immediate.iterator();
        while (iter.hasNext()) {
            InterfaceTypeImpl interfaze = (InterfaceTypeImpl) iter.next();
            interfaze.addInterfaces(list);
        }
        ClassTypeImpl superclass = (ClassTypeImpl) superclass();
        if (superclass != null) {
            superclass.addInterfaces(list);
        }
    }

    
Returns all the implemented interfaces recursively

Returns:A list of all the implemented interfaces (recursively)
/**
     * Returns all the implemented interfaces recursively
     * @return A list of all the implemented interfaces (recursively)
     */
    final List<InterfaceType> getAllInterfaces() {
        List<InterfaceType> all = new ArrayList<>();
        addInterfaces(all);
        return all;
    }

    
Returns:A list of all methods (recursively)
/**
     * Shared implementation of {@linkplain ClassType#allMethods()} and
     * {@linkplain InterfaceType#allMethods()}
     * @return A list of all methods (recursively)
     */
    public final List<Method> allMethods() {
        ArrayList<Method> list = new ArrayList<>(methods());
        ClassType clazz = superclass();
        while (clazz != null) {
            list.addAll(clazz.methods());
            clazz = clazz.superclass();
        }
        /*
         * Avoid duplicate checking on each method by iterating through
         * duplicate-free allInterfaces() rather than recursing
         */
        for (InterfaceType interfaze : getAllInterfaces()) {
            list.addAll(interfaze.methods());
        }
        return list;
    }

    @Override
    final List<ReferenceType> inheritedTypes() {
        List<ReferenceType> inherited = new ArrayList<>();
        if (superclass() != null) {
            inherited.add(0, superclass()); /* insert at front */
        }
        for (ReferenceType rt : interfaces()) {
            inherited.add(rt);
        }
        return inherited;
    }

    private PacketStream sendInvokeCommand(final ThreadReferenceImpl thread,
                                           final MethodImpl method,
                                           final ValueImpl[] args,
                                           final int options) {
        /*
         * Cache the values of args when TRACE_SENDS is enabled, for later printing.
         * If not cached, printing causes a remote call while synchronized, and deadlock.
         */
        if ((vm.traceFlags & VirtualMachineImpl.TRACE_SENDS) != 0) {
           for (ValueImpl arg: args) {
              arg.toString();
           }
        }
        CommandSender sender = getInvokeMethodSender(thread, method, args, options);
        PacketStream stream;
        if ((options & ClassType.INVOKE_SINGLE_THREADED) != 0) {
            stream = thread.sendResumingCommand(sender);
        } else {
            stream = vm.sendResumingCommand(sender);
        }
        return stream;
    }

    private void validateMethodInvocation(Method method)
                                            throws InvalidTypeException,
                                                   InvocationException {
        if (!canInvoke(method)) {
            throw new IllegalArgumentException("Invalid method");
        }
        /*
         * Method must be a static and not a static initializer
         */
        if (!method.isStatic()) {
            throw new IllegalArgumentException("Cannot invoke instance method on a class/interface type");
        } else if (method.isStaticInitializer()) {
            throw new IllegalArgumentException("Cannot invoke static initializer");
        }
    }

    
A subclass will provide specific CommandSender 
Params:
  • thread – the current invocation thread
  • method – the method to invoke
  • args – the arguments to pass to the method
  • options – the integer bit flag options
Returns:the specific CommandSender instance
/**
     * A subclass will provide specific {@linkplain CommandSender}
     * @param thread the current invocation thread
     * @param method the method to invoke
     * @param args the arguments to pass to the method
     * @param options the integer bit flag options
     * @return the specific {@literal CommandSender} instance
     */
    abstract CommandSender getInvokeMethodSender(ThreadReferenceImpl thread,
                                                 MethodImpl method,
                                                 ValueImpl[] args,
                                                 int options);

    
Waits for the reply to the last sent command

Params:
  • stream – the stream to listen for the reply on
Throws:
Returns:the InvocationResult instance
/**
     * Waits for the reply to the last sent command
     * @param stream the stream to listen for the reply on
     * @return the {@linkplain InvocationResult} instance
     * @throws JDWPException when something goes wrong in JDWP
     */
    abstract InvocationResult waitForReply(PacketStream stream) throws JDWPException;

    
Get the ReferenceType superclass 
Returns:the superclass or null
/**
     * Get the {@linkplain ReferenceType} superclass
     * @return the superclass or null
     */
    abstract ClassType superclass();

    
Get the implemented/extended interfaces

Returns:the list of implemented/extended interfaces
/**
     * Get the implemented/extended interfaces
     * @return the list of implemented/extended interfaces
     */
    abstract List<InterfaceType> interfaces();

    
Checks the provided method whether it can be invoked

Params:
  • method – the method to check
Returns:TRUE if the implementation knows how to invoke the method, FALSE otherwise
/**
     * Checks the provided method whether it can be invoked
     * @param method the method to check
     * @return {@code TRUE} if the implementation knows how to invoke the method,
     *         {@code FALSE} otherwise
     */
    abstract boolean canInvoke(Method method);
}