mappedpropertydescriptor.java

来自「JAVA 文章管理系统源码」· Java 代码 · 共 563 行 · 第 1/2 页

                Class params[] = mappedWriteMethod.getParameterTypes();
                if (params.length != 2) {
                    throw new IntrospectionException
                            ("bad mapped write method arg count");
                }
                if (mappedPropertyType != null &&
                        mappedPropertyType != params[1]) {
                    throw new IntrospectionException
                            ("type mismatch between mapped read and write methods");
                }
                mappedPropertyType = params[1];
            }
        } catch (IntrospectionException ex) {
            throw ex;
        }
    }


    /**
     * Return a capitalized version of the specified property name.
     *
     * @param s The property name
     */
    private static String capitalizePropertyName(String s) {
        if (s.length() == 0) {
            return s;
        }

        char chars[] = s.toCharArray();
        chars[0] = Character.toUpperCase(chars[0]);
        return new String(chars);
    }

    //======================================================================
    // Package private support methods (copied from java.beans.Introspector).
    //======================================================================

    // Cache of Class.getDeclaredMethods:
    private static java.util.Hashtable 
        declaredMethodCache = new java.util.Hashtable();

    /*
     * Internal method to return *public* methods within a class.
     */
    private static synchronized Method[] getPublicDeclaredMethods(Class clz) {
        // Looking up Class.getDeclaredMethods is relatively expensive,
        // so we cache the results.
        final Class fclz = clz;
        Method[] result = (Method[]) declaredMethodCache.get(fclz);
        if (result != null) {
            return result;
        }

        // We have to raise privilege for getDeclaredMethods
        result = (Method[])
                AccessController.doPrivileged(new PrivilegedAction() {
                    public Object run() {
                        try{
                        
                            return fclz.getDeclaredMethods();
                            
                        } catch (SecurityException ex) {
                            // this means we're in a limited security environment
                            // so let's try going through the public methods
                            // and null those those that are not from the declaring 
                            // class
                            Method[] methods = fclz.getMethods();
                            for (int i = 0, size = methods.length; i < size; i++) {
                                Method method =  methods[i];
                                if (!(fclz.equals(method.getDeclaringClass()))) {
                                    methods[i] = null;
                                }
                            }
                            return methods;
                        }
                    }
                });

        // Null out any non-public methods.
        for (int i = 0; i < result.length; i++) {
            Method method = result[i];
            if (method != null) {
                int mods = method.getModifiers();
                if (!Modifier.isPublic(mods)) {
                    result[i] = null;
                }
            }
        }

        // Add it to the cache.
        declaredMethodCache.put(clz, result);
        return result;
    }

    /**
     * Internal support for finding a target methodName on a given class.
     */
    private static Method internalFindMethod(Class start, String methodName,
                                             int argCount) {
        // For overridden methods we need to find the most derived version.
        // So we start with the given class and walk up the superclass chain.
        for (Class cl = start; cl != null; cl = cl.getSuperclass()) {
            Method methods[] = getPublicDeclaredMethods(cl);
            for (int i = 0; i < methods.length; i++) {
                Method method = methods[i];
                if (method == null) {
                    continue;
                }
                // skip static methods.
                int mods = method.getModifiers();
                if (Modifier.isStatic(mods)) {
                    continue;
                }
                if (method.getName().equals(methodName) &&
                        method.getParameterTypes().length == argCount) {
                    return method;
                }
            }
        }

        // Now check any inherited interfaces.  This is necessary both when
        // the argument class is itself an interface, and when the argument
        // class is an abstract class.
        Class ifcs[] = start.getInterfaces();
        for (int i = 0; i < ifcs.length; i++) {
            Method m = internalFindMethod(ifcs[i], methodName, argCount);
            if (m != null) {
                return m;
            }
        }

        return null;
    }

    /**
     * Internal support for finding a target methodName with a given
     * parameter list on a given class.
     */
    private static Method internalFindMethod(Class start, String methodName,
                                             int argCount, Class args[]) {
        // For overriden methods we need to find the most derived version.
        // So we start with the given class and walk up the superclass chain.
        for (Class cl = start; cl != null; cl = cl.getSuperclass()) {
            Method methods[] = getPublicDeclaredMethods(cl);
            for (int i = 0; i < methods.length; i++) {
                Method method = methods[i];
                if (method == null) {
                    continue;
                }
                // skip static methods.
                int mods = method.getModifiers();
                if (Modifier.isStatic(mods)) {
                    continue;
                }
                // make sure method signature matches.
                Class params[] = method.getParameterTypes();
                if (method.getName().equals(methodName) &&
                        params.length == argCount) {
                    boolean different = false;
                    if (argCount > 0) {
                        for (int j = 0; j < argCount; j++) {
                            if (params[j] != args[j]) {
                                different = true;
                                continue;
                            }
                        }
                        if (different) {
                            continue;
                        }
                    }
                    return method;
                }
            }
        }

        // Now check any inherited interfaces.  This is necessary both when
        // the argument class is itself an interface, and when the argument
        // class is an abstract class.
        Class ifcs[] = start.getInterfaces();
        for (int i = 0; i < ifcs.length; i++) {
            Method m = internalFindMethod(ifcs[i], methodName, argCount);
            if (m != null) {
                return m;
            }
        }
        
        return null;
    }

    /**
     * Find a target methodName on a given class.
     */
    static Method findMethod(Class cls, String methodName, int argCount)
            throws IntrospectionException {
        if (methodName == null) {
            return null;
        }

        Method m = internalFindMethod(cls, methodName, argCount);
        if (m != null) {
            return m;
        }

        // We failed to find a suitable method
        throw new IntrospectionException("No method \"" + methodName +
                "\" with " + argCount + " arg(s)");
    }

    /**
     * Find a target methodName with specific parameter list on a given class.
     */
    static Method findMethod(Class cls, String methodName, int argCount,
                             Class args[]) throws IntrospectionException {
        if (methodName == null) {
            return null;
        }

        Method m = internalFindMethod(cls, methodName, argCount, args);
        if (m != null) {
            return m;
        }

        // We failed to find a suitable method
        throw new IntrospectionException("No method \"" + methodName +
                "\" with " + argCount + " arg(s) of matching types.");
    }

    /**
     * Return true if class a is either equivalent to class b, or
     * if class a is a subclass of class b, ie if a either "extends"
     * or "implements" b.
     * Note tht either or both "Class" objects may represent interfaces.
     */
    static boolean isSubclass(Class a, Class b) {
        // We rely on the fact that for any given java class or
        // primtitive type there is a unqiue Class object, so
        // we can use object equivalence in the comparisons.
        if (a == b) {
            return true;
        }

        if (a == null || b == null) {
            return false;
        }

        for (Class x = a; x != null; x = x.getSuperclass()) {
            if (x == b) {
                return true;
            }

            if (b.isInterface()) {
                Class interfaces[] = x.getInterfaces();
                for (int i = 0; i < interfaces.length; i++) {
                    if (isSubclass(interfaces[i], b)) {
                        return true;
                    }
                }
            }
        }

        return false;
    }


    /**
     * Return true iff the given method throws the given exception.
     */

    private boolean throwsException(Method method, Class exception) {

        Class exs[] = method.getExceptionTypes();
        for (int i = 0; i < exs.length; i++) {
            if (exs[i] == exception) {
                return true;
            }
        }

        return false;
    }
}