+ * + * {@code LiveStackFrame} represents a frame storing data and partial results. + * Each frame has its own array of local variables (JVMS section 2.6.1), + * its own operand stack (JVMS section 2.6.2) for a method invocation. + * + * @jvms 2.6 Frames + */ +/* package-private */ +interface LiveStackFrame extends StackFrame { + /** + * Return the monitors held by this stack frame. This method returns + * an empty array if no monitor is held by this stack frame. + * + * @return the monitors held by this stack frames + */ + public Object[] getMonitors(); + + /** + * Gets the local variable array of this stack frame. + * + *
A single local variable can hold a value of type boolean, byte, char, + * short, int, float, reference or returnAddress. A pair of local variables + * can hold a value of type long or double. In other words, + * a value of type long or type double occupies two consecutive local + * variables. For a value of primitive type, the element in the + * local variable array is an {@link PrimitiveValue} object; + * otherwise, the element is an {@code Object}. + * + * @return the local variable array of this stack frame. + */ + public Object[] getLocals(); + + /** + * Gets the operand stack of this stack frame. + * + *
+ * The 0-th element of the returned array represents the top of the operand stack. + * This method returns an empty array if the operand stack is empty. + * + *
Each entry on the operand stack can hold a value of any Java Virtual + * Machine Type. + * For a value of primitive type, the element in the returned array is + * an {@link PrimitiveValue} object; otherwise, the element is the {@code Object} + * on the operand stack. + * + * @return the operand stack of this stack frame. + */ + public Object[] getStack(); + + /** + * UNSUPPORTED This interface is intended to be package-private + * or move to an internal package.
+ *
+ * Represents a local variable or an entry on the operand whose value is
+ * of primitive type.
+ */
+ public abstract class PrimitiveValue {
+ /**
+ * Returns the base type of this primitive value, one of
+ * {@code B, D, C, F, I, J, S, Z}.
+ *
+ * @return Name of a base type
+ * @jvms table 4.3-A
+ */
+ abstract char type();
+
+ /**
+ * Returns the boolean value if this primitive value is of type boolean.
+ * @return the boolean value if this primitive value is of type boolean.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type boolean.
+ */
+ public boolean booleanValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the int value if this primitive value is of type int.
+ * @return the int value if this primitive value is of type int.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type int.
+ */
+ public int intValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the long value if this primitive value is of type long.
+ * @return the long value if this primitive value is of type long.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type long.
+ */
+ public long longValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the char value if this primitive value is of type char.
+ * @return the char value if this primitive value is of type char.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type char.
+ */
+ public char charValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the byte value if this primitive value is of type byte.
+ * @return the byte value if this primitive value is of type byte.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type byte.
+ */
+ public byte byteValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the short value if this primitive value is of type short.
+ * @return the short value if this primitive value is of type short.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type short.
+ */
+ public short shortValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the float value if this primitive value is of type float.
+ * @return the float value if this primitive value is of type float.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type float.
+ */
+ public float floatValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+
+ /**
+ * Returns the double value if this primitive value is of type double.
+ * @return the double value if this primitive value is of type double.
+ *
+ * @throws UnsupportedOperationException if this primitive value is not
+ * of type double.
+ */
+ public double doubleValue() {
+ throw new UnsupportedOperationException("this primitive of type " + type());
+ }
+ }
+
+
+ /**
+ * Gets {@code StackWalker} that can get locals and operands.
+ *
+ * @throws SecurityException if the security manager is present and
+ * denies access to {@code RuntimePermission("liveStackFrames")}
+ */
+ public static StackWalker getStackWalker() {
+ return getStackWalker(EnumSet.noneOf(StackWalker.Option.class));
+ }
+
+ /**
+ * Gets a {@code StackWalker} instance with the given options specifying
+ * the stack frame information it can access, and which will traverse at most
+ * the given {@code maxDepth} number of stack frames. If no option is
+ * specified, this {@code StackWalker} obtains the method name and
+ * the class name with all
+ * {@linkplain StackWalker.Option#SHOW_HIDDEN_FRAMES hidden frames} skipped.
+ * The returned {@code StackWalker} can get locals and operands.
+ *
+ * @param options stack walk {@link StackWalker.Option options}
+ *
+ * @throws SecurityException if the security manager is present and
+ * it denies access to {@code RuntimePermission("liveStackFrames")}; or
+ * or if the given {@code options} contains
+ * {@link StackWalker.Option#RETAIN_CLASS_REFERENCE Option.RETAIN_CLASS_REFERENCE}
+ * and it denies access to {@code StackFramePermission("retainClassReference")}.
+ */
+ public static StackWalker getStackWalker(Set