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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scala.tools.util.debug;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
/**
* This class is intended to help debugging applications. It provides
* functions to abort the application and to turn objects into
* strings.
*
* In order to turn objects into strings, the class maintains a list
* of debuggers. An application using this class should configure it
* by adding debuggers for its data types (see method "addDebugger").
*
* Each time an object has to be transformed into a string, the list
* of debuggers is searched from the last added one to the first one
* for a debugger that is able to make that transformation. The first
* that is found, is then used to make the transformation.
*/
public class Debug {
//########################################################################
// Private Variables
/** The list of all available debuggers */
private static final ArrayList/*<Debugger>*/ debuggers = new ArrayList();
static {
addDebugger(ObjectDebugger.object);
addDebugger(ArrayDebugger.object);
addDebugger(ThrowableDebugger.object);
addDebugger(new ToStringDebugger(String.class));
}
//########################################################################
// Public Methods - Configuring
/** Adds the specified debugger to the list of debuggers. */
public static void addDebugger(Debugger debugger) {
debuggers.add(debugger);
}
//########################################################################
// Public Methods - Aborting
/** Aborts the application by throwing an AbortError. */
public static Error abort() {
throw new AbortError();
}
public static Error abort(Throwable cause) {
throw new AbortError(cause);
}
public static Error abort(Object object) {
return abort(show(object));
}
public static Error abort(Object object, Throwable cause) {
return abort(show(object), cause);
}
public static Error abort(String message) {
throw new AbortError(message);
}
public static Error abort(String message, Throwable cause) {
throw new AbortError(message, cause);
}
public static Error abort(String message, Object object) {
return abort(message + ": " + show(object));
}
public static Error abort(String message, Object object, Throwable cause) {
return abort(message + ": " + show(object), cause);
}
/** Aborts the application by throwing an AbortError. */
public static Error abortIllegalCase(int value) {
return abort("illegal case: " + value);
}
public static Error abortIllegalCase(Object object) {
return abort("illegal case", object);
}
//########################################################################
// Public Methods - Showing
/**
* Makes a string out of the object(s) using for each the first
* matching debugger and separating them with dash(es).
*/
public static String show(Object a) {
return showAll(new Object[] {a});
}
public static String show(Object a, Object b) {
return showAll(new Object[] {a, b});
}
public static String show(Object a, Object b, Object c) {
return showAll(new Object[] {a, b, c});
}
public static String show(Object a, Object b, Object c, Object d) {
return showAll(new Object[] {a, b, c, d});
}
public static String show(Object a, Object b, Object c, Object d, Object e)
{
return showAll(new Object[] {a, b, c, d, e});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f)
{
return showAll(new Object[] {a, b, c, d, e, f});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g)
{
return showAll(new Object[] {a, b, c, d, e, f, g});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g, Object h)
{
return showAll(new Object[] {a, b, c, d, e, f, g, h});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g, Object h, Object i)
{
return showAll(new Object[] {a, b, c, d, e, f, g, h, i});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g, Object h, Object i, Object j)
{
return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g, Object h, Object i, Object j, Object k)
{
return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j, k});
}
public static String show(Object a, Object b, Object c, Object d, Object e,
Object f, Object g, Object h, Object i, Object j, Object k, Object l)
{
return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j, k, l});
}
/**
* Makes a string out of all objects using for each the first
* matching debugger and separating them with dashes.
*/
public static String showAll(Object[] objects) {
return showAll(objects, " - ");
}
/**
* Makes a string out of all objects using for each the first
* matching debugger and separating them with the specified
* separator if it is non-null and by nothing otherwise.
*/
public static String showAll(Object[] objects, String separator) {
StringBuffer buffer = new StringBuffer();
appendAll(buffer, objects, separator);
return buffer.toString();
}
//########################################################################
// Public Methods - Appending
/**
* Appends the object to the buffer using the first matching
* debugger.
*/
public static void append(StringBuffer buffer, Object object) {
if (object != null) {
for (int i = debuggers.size() - 1; i >= 0; i--) {
Debugger debugger = (Debugger)debuggers.get(i);
if (!debugger.canAppend(object)) continue;
debugger.append(buffer, object);
return;
}
}
buffer.append(object);
}
/**
* Appends all the objects to the buffer using for each the first
* matching debugger. The object are separated by the specified
* separator if it is non-null and by nothing otherwise.
*/
public static void appendAll(StringBuffer buffer, Object[] objects,
String separator)
{
for (int i = 0; i < objects.length; i++) {
if (i > 0 && separator != null) buffer.append(separator);
append(buffer, objects[i]);
}
}
//########################################################################
// Public Methods - Miscellaneous
/**
* Returns the class name of the object. Does some pretty printing
* for parameterless pico case classes.
*/
public static String getClassNameOf(Object object) {
if (object == null) return "null";
Class clasz = object.getClass();
String name = clasz.getName();
if (!name.endsWith("$$Var")) return name;
Class superclass = clasz.getSuperclass();
Field[] fields = superclass.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
try {
Field field = fields[i];
if (field.getType() != clasz) continue;
if (!Modifier.isStatic(field.getModifiers())) continue;
Object value = field.get(null);
if (value != object) continue;
return name + "[" + field.getName() + "]";
} catch (IllegalAccessException exception) {
// continue
}
}
return name;
}
/** Returns true iff the object overrides "Object.toString()". */
public static boolean overridesToString(Object object) {
try {
Class clasz = object.getClass();
Method toString = clasz.getMethod("toString", new Class[0]);
return toString.getDeclaringClass() != Object.class;
} catch (NoSuchMethodException exception) {
return false;
} catch (SecurityException exception) {
return false;
}
}
//########################################################################
}
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