--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/com/sun/jdi/ObjectReference.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,451 @@
+/*
+ * Copyright 1998-2006 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package com.sun.jdi;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An object that currently exists in the target VM. An ObjectReference
+ * mirrors only the object itself and is not specific to any
+ * {@link Field} or {@link LocalVariable} to which it is currently
+ * assigned. An ObjectReference can
+ * have 0 or more references from field(s) and/or variable(s).
+ * <p>
+ * Any method on <code>ObjectReference</code> which directly or
+ * indirectly takes <code>ObjectReference</code> as an parameter may throw
+ * {@link com.sun.jdi.VMDisconnectedException} if the target VM is
+ * disconnected and the {@link com.sun.jdi.event.VMDisconnectEvent} has been or is
+ * available to be read from the {@link com.sun.jdi.event.EventQueue}.
+ * <p>
+ * Any method on <code>ObjectReference</code> which directly or
+ * indirectly takes <code>ObjectReference</code> as an parameter may throw
+ * {@link com.sun.jdi.VMOutOfMemoryException} if the target VM has run out of memory.
+ * <p>
+ * Any method on <code>ObjectReference</code> or which directly or indirectly takes
+ * <code>ObjectReference</code> as parameter may throw
+ * {@link com.sun.jdi.ObjectCollectedException} if the mirrored object has been
+ * garbage collected.
+ *
+ * @author Robert Field
+ * @author Gordon Hirsch
+ * @author James McIlree
+ * @since 1.3
+ */
+public interface ObjectReference extends Value
+{
+ /**
+ * Gets the {@link ReferenceType} that mirrors the type
+ * of this object. The type may be a subclass or implementor of the
+ * declared type of any field or variable which currently holds it.
+ * For example, right after the following statement.
+ * <p>
+ * <code>Object obj = new String("Hello, world!");</code>
+ * <p>
+ * The ReferenceType of obj will mirror java.lang.String and not
+ * java.lang.Object.
+ * <p>
+ * The type of an object never changes, so this method will
+ * always return the same ReferenceType over the lifetime of the
+ * mirrored object.
+ * <p>
+ * The returned ReferenceType will be a {@link ClassType} or
+ * {@link ArrayType} and never an {@link InterfaceType}.
+ *
+ * @return the {@link ReferenceType} for this object.
+ */
+ ReferenceType referenceType();
+
+ /**
+ * Gets the value of a given instance or static field in this object.
+ * The Field must be valid for this ObjectReference;
+ * that is, it must be from
+ * the mirrored object's class or a superclass of that class.
+ *
+ * @param sig the field containing the requested value
+ * @return the {@link Value} of the instance field.
+ * @throws java.lang.IllegalArgumentException if the field is not valid for
+ * this object's class.
+ */
+ Value getValue(Field sig);
+
+ /**
+ * Gets the value of multiple instance and/or static fields in this object.
+ * The Fields must be valid for this ObjectReference;
+ * that is, they must be from
+ * the mirrored object's class or a superclass of that class.
+ *
+ * @param fields a list of {@link Field} objects containing the
+ * requested values.
+ * @return a Map of the requested {@link Field} objects with
+ * their {@link Value}.
+ * @throws java.lang.IllegalArgumentException if any field is not valid for
+ * this object's class.
+ */
+ Map<Field,Value> getValues(List<? extends Field> fields);
+
+ /**
+ * Sets the value of a given instance or static field in this object.
+ * The {@link Field} must be valid for this ObjectReference; that is,
+ * it must be from the mirrored object's class or a superclass of that class.
+ * If static, the field must not be final.
+ * <p>
+ * Object values must be assignment compatible with the field type
+ * (This implies that the field type must be loaded through the
+ * enclosing class's class loader). Primitive values must be
+ * either assignment compatible with the field type or must be
+ * convertible to the field type without loss of information.
+ * See the <a href="http://java.sun.com/docs/books/jls/">
+ * Java<sup><font size=-2>TM</font></sup> Language Specification</a>.
+ * section
+ * <a href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#184206">5.2</a>
+ * for more information on assignment
+ * compatibility.
+ *
+ * @param field the field containing the requested value
+ * @param value the new value to assign
+ * @throws java.lang.IllegalArgumentException if the field is not valid for
+ * this object's class.
+ * @throws InvalidTypeException if the value's type does not match
+ * the field's type.
+ * @throws ClassNotLoadedException if 'value' is not null, and the field
+ * type has not yet been loaded through the appropriate class loader.
+ * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
+ */
+ void setValue(Field field, Value value)
+ throws InvalidTypeException, ClassNotLoadedException;
+
+ /** Perform method invocation with only the invoking thread resumed */
+ static final int INVOKE_SINGLE_THREADED = 0x1;
+ /** Perform non-virtual method invocation */
+ static final int INVOKE_NONVIRTUAL = 0x2;
+
+ /**
+ * Invokes the specified {@link Method} on this object in the
+ * target VM. The
+ * specified method can be defined in this object's class,
+ * in a superclass of this object's class, or in an interface
+ * implemented by this object. The method may be a static method
+ * or an instance method, but not a static initializer or constructor.
+ * Use {@link ClassType#newInstance} to create a new object and
+ * run its constructor.
+ * <p>
+ * The method invocation will occur in the specified thread.
+ * Method invocation can occur only if the specified thread
+ * has been suspended by an event which occurred in that thread.
+ * Method invocation is not supported
+ * when the target VM has been suspended through
+ * {@link VirtualMachine#suspend} or when the specified thread
+ * is suspended through {@link ThreadReference#suspend}.
+ * <p>
+ * The specified method is invoked with the arguments in the specified
+ * argument list. The method invocation is synchronous; this method
+ * does not return until the invoked method returns in the target VM.
+ * If the invoked method throws an exception, this method
+ * will throw an {@link InvocationException} which contains
+ * a mirror to the exception object thrown.
+ * <p>
+ * 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.
+ * If the method being called accepts a variable number of arguments,
+ * then the last argument type is an array of some component type.
+ * The argument in the matching position can be omitted, or can be null,
+ * an array of the same component type, or an argument of the
+ * component type followed by any number of other arguments of the same
+ * type. If the argument is omitted, then a 0 length array of the
+ * component type is passed. The component type can be a primitive type.
+ * Autoboxing is not supported.
+ *
+ * See the <a href="http://java.sun.com/docs/books/jls/">
+ * Java Language Specification</a>.
+ * section
+ * <a href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#184206">5.2</a>
+ * for more information on assignment compatibility.
+ * <p>
+ * By default, the method is invoked using dynamic lookup as
+ * documented in the
+ * <a href="http://java.sun.com/docs/books/jls/">
+ * Java Language Specification</a>
+ * second edition, section
+ * <a href="http://java.sun.com/docs/books/jls/second_edition/html/expressions.doc.html#45606">15.12.4.4</a>;
+ * in particular, overriding based on the runtime type of the object
+ * mirrored by this {@link ObjectReference} will occur. This
+ * behavior can be changed by specifying the
+ * {@link #INVOKE_NONVIRTUAL} bit flag in the <code>options</code>
+ * argument. If this flag is set, the specified method is invoked
+ * whether or not it is overridden for this object's runtime type.
+ * The method, in this case, must not belong to an interface and
+ * must not be abstract. This option is useful for performing method
+ * invocations like those done with the <code>super</code> keyword in
+ * the Java programming language.
+ * <p>
+ * By default, all threads in the target VM are resumed while
+ * the method is being invoked if they were previously
+ * suspended by an event or by {@link VirtualMachine#suspend} or
+ * {@link ThreadReference#suspend}. This is done to prevent the deadlocks
+ * that will occur if any of the threads own monitors
+ * that will be needed by the invoked method.
+ * Note, however, that this implicit resume acts exactly like
+ * {@link ThreadReference#resume}, so if the thread's suspend
+ * count is greater than 1, it will remain in a suspended state
+ * during the invocation and thus a deadlock could still occur.
+ * By default, when the invocation completes,
+ * all threads in the target VM are suspended, regardless their state
+ * before the invocation.
+ * It is possible that
+ * breakpoints or other events might occur during the invocation.
+ * This can cause deadlocks as described above. It can also cause a deadlock
+ * if invokeMethod is called from the client's event handler thread. In this
+ * case, this thread will be waiting for the invokeMethod to complete and
+ * won't read the EventSet that comes in for the new event. If this
+ * new EventSet is SUSPEND_ALL, then a deadlock will occur because no
+ * one will resume the EventSet. To avoid this, all EventRequests should
+ * be disabled before doing the invokeMethod, or the invokeMethod should
+ * not be done from the client's event handler thread.
+ * <p>
+ * The resumption of other threads during the invocation can be prevented
+ * by specifying the {@link #INVOKE_SINGLE_THREADED}
+ * bit flag in the <code>options</code> argument; however,
+ * there is no protection against or recovery from the deadlocks
+ * described above, so this option should be used with great caution.
+ * Only the specified thread will be resumed (as described for all
+ * threads above). Upon completion of a single threaded invoke, the invoking thread
+ * will be suspended once again. Note that any threads started during
+ * the single threaded invocation will not be suspended when the
+ * invocation completes.
+ * <p>
+ * If the target VM is disconnected during the invoke (for example, through
+ * {@link VirtualMachine#dispose}) the method invocation continues.
+ *
+ * @param thread the thread in which to invoke.
+ * @param method the {@link Method} to invoke.
+ * @param arguments 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 object's class, if the size of the argument list
+ * does not match the number of declared arguemnts for the method,
+ * if the method is a constructor or static intializer, or
+ * if {@link #INVOKE_NONVIRTUAL} is specified and the method is
+ * either abstract or an interface member.
+ * @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()}.
+ */
+ Value invokeMethod(ThreadReference thread, Method method,
+ List<? extends Value> arguments, int options)
+ throws InvalidTypeException,
+ ClassNotLoadedException,
+ IncompatibleThreadStateException,
+ InvocationException;
+
+ /**
+ * Prevents garbage collection for this object. By default all
+ * {@link ObjectReference} values returned by JDI may be collected
+ * at any time the target VM is running. A call to this method
+ * guarantees that the object will not be collected.
+ * {@link #enableCollection} can be used to allow collection once
+ * again.
+ * <p>
+ * Calls to this method are counted. Every call to this method
+ * requires a corresponding call to {@link #enableCollection} before
+ * garbage collection is re-enabled.
+ * <p>
+ * Note that while the target VM is suspended, no garbage collection
+ * will occur because all threads are suspended. The typical
+ * examination of variables, fields, and arrays during the suspension
+ * is safe without explicitly disabling garbage collection.
+ * <p>
+ * This method should be used sparingly, as it alters the
+ * pattern of garbage collection in the target VM and,
+ * consequently, may result in application behavior under the
+ * debugger that differs from its non-debugged behavior.
+ * @throws VMCannotBeModifiedException if the VirtualMachine is read-only
+ * -see {@link VirtualMachine#canBeModified()}.
+ */
+ void disableCollection();
+
+ /**
+ * Permits garbage collection for this object. By default all
+ * {@link ObjectReference} values returned by JDI may be collected
+ * at any time the target VM is running. A call to this method
+ * is necessary only if garbage collection was previously disabled
+ * with {@link #disableCollection}.
+ * @throws VMCannotBeModifiedException if the VirtualMachine is read-only
+ * -see {@link VirtualMachine#canBeModified()}.
+ */
+ void enableCollection();
+
+ /**
+ * Determines if this object has been garbage collected in the target
+ * VM.
+ *
+ * @return <code>true</code> if this {@link ObjectReference} has been collected;
+ * <code>false</code> otherwise.
+ * @throws VMCannotBeModifiedException if the VirtualMachine is read-only
+ * -see {@link VirtualMachine#canBeModified()}.
+ */
+ boolean isCollected();
+
+ /**
+ * Returns a unique identifier for this ObjectReference.
+ * It is guaranteed to be unique among all
+ * ObjectReferences from the same VM that have not yet been disposed.
+ * The guarantee applies as long
+ * as this ObjectReference has not yet been disposed.
+ *
+ * @return a long unique ID
+ */
+ long uniqueID();
+
+ /**
+ * Returns a List containing a {@link ThreadReference} for
+ * each thread currently waiting for this object's monitor.
+ * See {@link ThreadReference#currentContendedMonitor} for
+ * information about when a thread is considered to be waiting
+ * for a monitor.
+ * <p>
+ * Not all target VMs support this operation. See
+ * VirtualMachine#canGetMonitorInfo to determine if the
+ * operation is supported.
+ *
+ * @return a List of {@link ThreadReference} objects. The list
+ * has zero length if no threads are waiting for the monitor.
+ * @throws java.lang.UnsupportedOperationException if the
+ * target VM does not support this operation.
+ * @throws IncompatibleThreadStateException if any
+ * waiting thread is not suspended
+ * in the target VM
+ */
+ List<ThreadReference> waitingThreads()
+ throws IncompatibleThreadStateException;
+
+ /**
+ * Returns an {@link ThreadReference} for the thread, if any,
+ * which currently owns this object's monitor.
+ * See {@link ThreadReference#ownedMonitors} for a definition
+ * of ownership.
+ * <p>
+ * Not all target VMs support this operation. See
+ * VirtualMachine#canGetMonitorInfo to determine if the
+ * operation is supported.
+ *
+ * @return the {@link ThreadReference} which currently owns the
+ * monitor, or null if it is unowned.
+ *
+ * @throws java.lang.UnsupportedOperationException if the
+ * target VM does not support this operation.
+ * @throws IncompatibleThreadStateException if the owning thread is
+ * not suspended in the target VM
+ */
+ ThreadReference owningThread() throws IncompatibleThreadStateException;
+
+ /**
+ * Returns the number times this object's monitor has been
+ * entered by the current owning thread.
+ * See {@link ThreadReference#ownedMonitors} for a definition
+ * of ownership.
+ * <p>
+ * Not all target VMs support this operation. See
+ * VirtualMachine#canGetMonitorInfo to determine if the
+ * operation is supported.
+ *
+ * @see #owningThread
+ * @return the integer count of the number of entries.
+ *
+ * @throws java.lang.UnsupportedOperationException if the
+ * target VM does not support this operation.
+ * @throws IncompatibleThreadStateException if the owning thread is
+ * not suspended in the target VM
+ */
+ int entryCount() throws IncompatibleThreadStateException;
+
+ /**
+ * Returns objects that directly reference this object.
+ * Only objects that are reachable for the purposes of garbage collection
+ * are returned. Note that an object can also be referenced in other ways,
+ * such as from a local variable in a stack frame, or from a JNI global
+ * reference. Such non-object referrers are not returned by this method.
+ * <p>
+ * Not all target virtual machines support this operation.
+ * Use {@link VirtualMachine#canGetInstanceInfo()}
+ * to determine if the operation is supported.
+ *
+ * @see VirtualMachine#instanceCounts(List)
+ * @see ReferenceType#instances(long)
+
+ * @param maxReferrers The maximum number of referring objects to return.
+ * Must be non-negative. If zero, all referring
+ * objects are returned.
+ * @return a of List of {@link ObjectReference} objects. If there are
+ * no objects that reference this object, a zero-length list is returned..
+ * @throws java.lang.UnsupportedOperationException if
+ * the target virtual machine does not support this
+ * operation - see
+ * {@link VirtualMachine#canGetInstanceInfo() canGetInstanceInfo()}
+ * @throws java.lang.IllegalArgumentException if maxReferrers is less
+ * than zero.
+ * @since 1.6
+ */
+ List<ObjectReference> referringObjects(long maxReferrers);
+
+
+ /**
+ * Compares the specified Object with this ObjectReference for equality.
+ *
+ * @return true if the Object is an ObjectReference, if the
+ * ObjectReferences belong to the same VM, and if applying the
+ * "==" operator on the mirrored objects in that VM evaluates to true.
+ */
+ boolean equals(Object obj);
+
+ /**
+ * Returns the hash code value for this ObjectReference.
+ *
+ * @return the integer hash code
+ */
+ int hashCode();
+}