| /* |
| * Copyright (c) 1998, 2013, 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 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 |
| */ |
| @jdk.Exported |
| 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 section 5.2 of |
| * <cite>The Java™ Language Specification</cite> |
| * 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 section 5.2 of |
| * <cite>The Java™ Language Specification</cite> |
| * for more information on assignment compatibility. |
| * <p> |
| * By default, the method is invoked using dynamic lookup as |
| * documented in section 15.12.4.4 of |
| * <cite>The Java™ Language Specification</cite> |
| * 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 have an implementation, either in a class |
| * or an interface. 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 arguments 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 a non-default 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(); |
| } |
