introspectionutils.java

业界著名的tomcat服务器的最新6.0的源代码。

            String cpathProp, boolean addTools) throws IOException,
            MalformedURLException {
        Vector jarsV = new Vector();
        if (dir != null) {
            // Add dir/classes first, if it exists
            URL url = getURL(dir, "classes");
            if (url != null)
                jarsV.addElement(url);
            addToClassPath(jarsV, dir);
        }

        if (cpath != null)
            addJarsFromClassPath(jarsV, cpath);

        if (cpathProp != null) {
            String cpath1 = System.getProperty(cpathProp);
            addJarsFromClassPath(jarsV, cpath1);
        }

        if (addTools)
            addToolsJar(jarsV);

        return getClassPath(jarsV);
    }

    // -------------------- Mapping command line params to setters

    public static boolean processArgs(Object proxy, String args[])
            throws Exception {
        String args0[] = null;
        if (null != findMethod(proxy.getClass(), "getOptions1", new Class[] {})) {
            args0 = (String[]) callMethod0(proxy, "getOptions1");
        }

        if (args0 == null) {
            //args0=findVoidSetters(proxy.getClass());
            args0 = findBooleanSetters(proxy.getClass());
        }
        Hashtable h = null;
        if (null != findMethod(proxy.getClass(), "getOptionAliases",
                new Class[] {})) {
            h = (Hashtable) callMethod0(proxy, "getOptionAliases");
        }
        return processArgs(proxy, args, args0, null, h);
    }

    public static boolean processArgs(Object proxy, String args[],
            String args0[], String args1[], Hashtable aliases) throws Exception {
        for (int i = 0; i < args.length; i++) {
            String arg = args[i];
            if (arg.startsWith("-"))
                arg = arg.substring(1);
            if (aliases != null && aliases.get(arg) != null)
                arg = (String) aliases.get(arg);

            if (args0 != null) {
                boolean set = false;
                for (int j = 0; j < args0.length; j++) {
                    if (args0[j].equalsIgnoreCase(arg)) {
                        setProperty(proxy, args0[j], "true");
                        set = true;
                        break;
                    }
                }
                if (set)
                    continue;
            }
            if (args1 != null) {
                for (int j = 0; j < args1.length; j++) {
                    if (args1[j].equalsIgnoreCase(arg)) {
                        i++;
                        if (i >= args.length)
                            return false;
                        setProperty(proxy, arg, args[i]);
                        break;
                    }
                }
            } else {
                // if args1 is not specified,assume all other options have param
                i++;
                if (i >= args.length)
                    return false;
                setProperty(proxy, arg, args[i]);
            }

        }
        return true;
    }

    // -------------------- other utils --------------------
    public static void clear() {
        objectMethods.clear();
    }
    
    public static String[] findVoidSetters(Class c) {
        Method m[] = findMethods(c);
        if (m == null)
            return null;
        Vector v = new Vector();
        for (int i = 0; i < m.length; i++) {
            if (m[i].getName().startsWith("set")
                    && m[i].getParameterTypes().length == 0) {
                String arg = m[i].getName().substring(3);
                v.addElement(unCapitalize(arg));
            }
        }
        String s[] = new String[v.size()];
        for (int i = 0; i < s.length; i++) {
            s[i] = (String) v.elementAt(i);
        }
        return s;
    }

    public static String[] findBooleanSetters(Class c) {
        Method m[] = findMethods(c);
        if (m == null)
            return null;
        Vector v = new Vector();
        for (int i = 0; i < m.length; i++) {
            if (m[i].getName().startsWith("set")
                    && m[i].getParameterTypes().length == 1
                    && "boolean".equalsIgnoreCase(m[i].getParameterTypes()[0]
                            .getName())) {
                String arg = m[i].getName().substring(3);
                v.addElement(unCapitalize(arg));
            }
        }
        String s[] = new String[v.size()];
        for (int i = 0; i < s.length; i++) {
            s[i] = (String) v.elementAt(i);
        }
        return s;
    }

    static Hashtable objectMethods = new Hashtable();

    public static Method[] findMethods(Class c) {
        Method methods[] = (Method[]) objectMethods.get(c);
        if (methods != null)
            return methods;

        methods = c.getMethods();
        objectMethods.put(c, methods);
        return methods;
    }

    public static Method findMethod(Class c, String name, Class params[]) {
        Method methods[] = findMethods(c);
        if (methods == null)
            return null;
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].getName().equals(name)) {
                Class methodParams[] = methods[i].getParameterTypes();
                if (methodParams == null)
                    if (params == null || params.length == 0)
                        return methods[i];
                if (params == null)
                    if (methodParams == null || methodParams.length == 0)
                        return methods[i];
                if (params.length != methodParams.length)
                    continue;
                boolean found = true;
                for (int j = 0; j < params.length; j++) {
                    if (params[j] != methodParams[j]) {
                        found = false;
                        break;
                    }
                }
                if (found)
                    return methods[i];
            }
        }
        return null;
    }

    /** Test if the object implements a particular
     *  method
     */
    public static boolean hasHook(Object obj, String methodN) {
        try {
            Method myMethods[] = findMethods(obj.getClass());
            for (int i = 0; i < myMethods.length; i++) {
                if (methodN.equals(myMethods[i].getName())) {
                    // check if it's overriden
                    Class declaring = myMethods[i].getDeclaringClass();
                    Class parentOfDeclaring = declaring.getSuperclass();
                    // this works only if the base class doesn't extend
                    // another class.

                    // if the method is declared in a top level class
                    // like BaseInterceptor parent is Object, otherwise
                    // parent is BaseInterceptor or an intermediate class
                    if (!"java.lang.Object".equals(parentOfDeclaring.getName())) {
                        return true;
                    }
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return false;
    }

    public static void callMain(Class c, String args[]) throws Exception {
        Class p[] = new Class[1];
        p[0] = args.getClass();
        Method m = c.getMethod("main", p);
        m.invoke(c, new Object[] { args });
    }

    public static Object callMethod1(Object target, String methodN,
            Object param1, String typeParam1, ClassLoader cl) throws Exception {
        if (target == null || param1 == null) {
            d("Assert: Illegal params " + target + " " + param1);
        }
        if (dbg > 0)
            d("callMethod1 " + target.getClass().getName() + " "
                    + param1.getClass().getName() + " " + typeParam1);

        Class params[] = new Class[1];
        if (typeParam1 == null)
            params[0] = param1.getClass();
        else
            params[0] = cl.loadClass(typeParam1);
        Method m = findMethod(target.getClass(), methodN, params);
        if (m == null)
            throw new NoSuchMethodException(target.getClass().getName() + " "
                    + methodN);
        return m.invoke(target, new Object[] { param1 });
    }

    public static Object callMethod0(Object target, String methodN)
            throws Exception {
        if (target == null) {
            d("Assert: Illegal params " + target);
            return null;
        }
        if (dbg > 0)
            d("callMethod0 " + target.getClass().getName() + "." + methodN);

        Class params[] = new Class[0];
        Method m = findMethod(target.getClass(), methodN, params);
        if (m == null)
            throw new NoSuchMethodException(target.getClass().getName() + " "
                    + methodN);
        return m.invoke(target, emptyArray);
    }

    static Object[] emptyArray = new Object[] {};

    public static Object callMethodN(Object target, String methodN,
            Object params[], Class typeParams[]) throws Exception {
        Method m = null;
        m = findMethod(target.getClass(), methodN, typeParams);
        if (m == null) {
            d("Can't find method " + methodN + " in " + target + " CLASS "
                    + target.getClass());
            return null;
        }
        Object o = m.invoke(target, params);

        if (dbg > 0) {
            // debug
            StringBuffer sb = new StringBuffer();
            sb.append("" + target.getClass().getName() + "." + methodN + "( ");
            for (int i = 0; i < params.length; i++) {
                if (i > 0)
                    sb.append(", ");
                sb.append(params[i]);
            }
            sb.append(")");
            d(sb.toString());
        }
        return o;
    }

    public static Object convert(String object, Class paramType) {
        Object result = null;
        if ("java.lang.String".equals(paramType.getName())) {
            result = object;
        } else if ("java.lang.Integer".equals(paramType.getName())
                || "int".equals(paramType.getName())) {
            try {
                result = new Integer(object);
            } catch (NumberFormatException ex) {
            }
            // Try a setFoo ( boolean )
        } else if ("java.lang.Boolean".equals(paramType.getName())
                || "boolean".equals(paramType.getName())) {
            result = new Boolean(object);

            // Try a setFoo ( InetAddress )
        } else if ("java.net.InetAddress".equals(paramType
                .getName())) {
            try {
                result = InetAddress.getByName(object);
            } catch (UnknownHostException exc) {
                d("Unable to resolve host name:" + object);
            }

            // Unknown type
        } else {
            d("Unknown type " + paramType.getName());
        }
        if (result == null) {
            throw new IllegalArgumentException("Can't convert argument: " + object);
        }
        return result;
    }
    
    // -------------------- Get property --------------------
    // This provides a layer of abstraction

    public static interface PropertySource {

        public String getProperty(String key);

    }

    public static interface AttributeHolder {

        public void setAttribute(String key, Object o);

    }

    // debug --------------------
    static final int dbg = 0;

    static void d(String s) {
        if (log.isDebugEnabled())
            log.debug("IntrospectionUtils: " + s);
    }
}