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	/*
	* 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;

	/**
	* The state of one method invocation on a thread's call stack.
	* As a thread executes, stack frames are pushed and popped from
	* its call stack as methods are invoked and then return. A StackFrame
	* mirrors one such frame from a target VM at some point in its
	* thread's execution. The call stack is, then, simply a List of
	* StackFrame objects. The call stack can be obtained any time a thread
	* is suspended through a call to {@link ThreadReference#frames}
	* <p>
	* StackFrames provide access to a method's local variables and their
	* current values.
	* <p>
	* The lifetime of a StackFrame is very limited. It is available only
	* for suspended threads and becomes invalid once its thread is resumed.
	* <p>
	* Any method on <code>StackFrame</code> which
	* takes <code>StackFrame</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>StackFrame</code> which
	* takes <code>StackFrame</code> as an parameter may throw
	* {@link com.sun.jdi.VMOutOfMemoryException} if the target VM has run out of memory.
	*
	* @author Robert Field
	* @author Gordon Hirsch
	* @author James McIlree
	* @since 1.3
	*/
	@jdk.Exported
	public interface StackFrame extends Mirror, Locatable {

	/**
	* Returns the {@link Location} of the current instruction in the frame.
	* The method for which this frame was created can also be accessed
	* through the returned location.
	* For the top frame in the stack, this location identifies the
	* next instruction to be executed. For all other frames, this
	* location identifies the instruction that caused the next frame's
	* method to be invoked.
	* If the frame represents a native method invocation, the returned
	* location indicates the class and method, but the code index will
	* not be valid (-1).
	*
	* @return the {@link Location} of the current instruction.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	*/
	Location location();

	/**
	* Returns the thread under which this frame's method is running.
	*
	* @return a {@link ThreadReference} which mirrors the frame's thread.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	*/
	ThreadReference thread();

	/**
	* Returns the value of 'this' for the current frame.
	* The {@link ObjectReference} for 'this' is only available for
	* non-native instance methods.
	*
	* @return an {@link ObjectReference}, or null if the frame represents
	* a native or static method.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	*/
	ObjectReference thisObject();

	/**
	* Returns a list containing each {@link LocalVariable}
	* that can be accessed from this frame's location.
	* <p>
	* Visibility is based on the code index of the current instruction of
	* this StackFrame. Each variable has a range of byte code indices in which
	* it is accessible.
	* If this stack frame's method
	* matches this variable's method and if the code index of this
	* StackFrame is within the variable's byte code range, the variable is
	* visible.
	* <p>
	* A variable's byte code range is at least as large as the scope of
	* that variable, but can continue beyond the end of the scope under
	* certain circumstances:
	* <ul>
	* <li>the compiler/VM does not immediately reuse the variable's slot.
	* <li>the compiler/VM is implemented to report the extended range that
	* would result from the item above.
	* </ul>
	* The advantage of an extended range is that variables from recently
	* exited scopes may remain available for examination (this is especially
	* useful for loop indices). If, as a result of the extensions above,
	* the current frame location is contained within the range
	* of multiple local variables of the same name, the variable with the
	* highest-starting range is chosen for the returned list.
	*
	* @return the list of {@link LocalVariable} objects currently visible;
	* the list will be empty if there are no visible variables;
	* specifically, frames in native methods will always return a
	* zero-length list.
	* @throws AbsentInformationException if there is no local variable
	* information for this method.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	* @throws NativeMethodException if the current method is native.
	*/
	List<LocalVariable> visibleVariables() throws AbsentInformationException;

	/**
	* Finds a {@link LocalVariable} that matches the given name and is
	* visible at the current frame location.
	* See {@link #visibleVariables} for more information on visibility.
	*
	* @param name the variable name to find
	* @return the matching {@link LocalVariable}, or null if there is no
	* visible variable with the given name; frames in native methods
	* will always return null.
	* @throws AbsentInformationException if there is no local variable
	* information for this method.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	* @throws NativeMethodException if the current method is native.
	*/
	LocalVariable visibleVariableByName(String name) throws AbsentInformationException;

	/**
	* Gets the {@link Value} of a {@link LocalVariable} in this frame.
	* The variable must be valid for this frame's method and visible
	* according to the rules described in {@link #visibleVariables}.
	*
	* @param variable the {@link LocalVariable} to be accessed
	* @return the {@link Value} of the instance field.
	* @throws java.lang.IllegalArgumentException if the variable is
	* either invalid for this frame's method or not visible.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	*/
	Value getValue(LocalVariable variable);

	/**
	* Returns the values of multiple local variables in this frame.
	* Each variable must be valid for this frame's method and visible
	* according to the rules described in {@link #visibleVariables}.
	*
	* @param variables a list of {@link LocalVariable} objects to be accessed
	* @return a map associating each {@link LocalVariable} with
	* its {@link Value}
	* @throws java.lang.IllegalArgumentException if any variable is
	* either invalid for this frame's method or not visible.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	*/
	Map<LocalVariable,Value> getValues(List<? extends LocalVariable> variables);

	/**
	* Sets the {@link Value} of a {@link LocalVariable} in this frame.
	* The variable must be valid for this frame's method and visible
	* according to the rules described in {@link #visibleVariables}.
	* <p>
	* Object values must be assignment compatible with the variable type
	* (This implies that the variable type must be loaded through the
	* enclosing class's class loader). Primitive values must be
	* either assignment compatible with the variable type or must be
	* convertible to the variable type without loss of information.
	* See JLS section 5.2 for more information on assignment
	* compatibility.
	*
	* @param variable 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 variable's type.
	* @throws ClassNotLoadedException if the variable type has not yet been loaded
	* through the appropriate class loader.
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	* @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
	*/
	void setValue(LocalVariable variable, Value value)
	throws InvalidTypeException, ClassNotLoadedException;

	/**
	* Returns the values of all arguments in this frame. Values are
	* returned even if no local variable information is present.
	*
	* @return a list containing a {@link Value} object for each argument
	* to this frame, in the order in which the arguments were
	* declared. If the method corresponding to this frame has
	* no arguments, an empty list is returned.
	*
	* @throws InvalidStackFrameException if this stack frame has become
	* invalid. Once the frame's thread is resumed, the stack frame is
	* no longer valid.
	* @since 1.6
	*/
	List<Value> getArgumentValues();

	}

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