mappedpropertydescriptor.java

APACHE 公司出的java bean 工具包

        findMappedPropertyType();
    }

    // -------------------------------------------------------- Public Methods

    /**
     * Gets the Class object for the property values.
     *
     * @return The Java type info for the property values.  Note that
     * the "Class" object may describe a built-in Java type such as "int".
     * The result may be "null" if this is a mapped property that
     * does not support non-keyed access.
     * <p>
     * This is the type that will be returned by the mappedReadMethod.
     */
    public Class getMappedPropertyType() {
        return mappedPropertyType;
    }

    /**
     * Gets the method that should be used to read one of the property value.
     *
     * @return The method that should be used to read the property value.
     * May return null if the property can't be read.
     */
    public Method getMappedReadMethod() {
        return mappedReadMethod;
    }

    /**
     * Sets the method that should be used to read one of the property value.
     *
     * @param mappedGetter The mapped getter method.
     * @throws IntrospectionException If an error occurs finding the
     * mapped property
     */
    public void setMappedReadMethod(Method mappedGetter)
            throws IntrospectionException {
        mappedReadMethod = mappedGetter;
        findMappedPropertyType();
    }

    /**
     * Gets the method that should be used to write one of the property value.
     *
     * @return The method that should be used to write one of the property value.
     * May return null if the property can't be written.
     */
    public Method getMappedWriteMethod() {
        return mappedWriteMethod;
    }

    /**
     * Sets the method that should be used to write the property value.
     *
     * @param mappedSetter The mapped setter method.
     * @throws IntrospectionException If an error occurs finding the
     * mapped property
     */
    public void setMappedWriteMethod(Method mappedSetter)
            throws IntrospectionException {
        mappedWriteMethod = mappedSetter;
        findMappedPropertyType();
    }

    // ------------------------------------------------------- Private Methods

    /**
     * Introspect our bean class to identify the corresponding getter
     * and setter methods.
     */
    private void findMappedPropertyType() throws IntrospectionException {
        try {
            mappedPropertyType = null;
            if (mappedReadMethod != null) {
                if (mappedReadMethod.getParameterTypes().length != 1) {
                    throw new IntrospectionException
                            ("bad mapped read method arg count");
                }
                mappedPropertyType = mappedReadMethod.getReturnType();
                if (mappedPropertyType == Void.TYPE) {
                    throw new IntrospectionException
                            ("mapped read method " +
                            mappedReadMethod.getName() + " returns void");
                }
            }

            if (mappedWriteMethod != null) {
                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);
    }

    /**
     * Find a method on a class with a specified number of parameters.
     */
    private static Method internalGetMethod(Class initial, String methodName,
                                            int parameterCount) {
        // 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 clazz = initial; clazz != null; clazz = clazz.getSuperclass()) {
            Method[] methods = clazz.getDeclaredMethods();
            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.isPublic(mods) ||
                    Modifier.isStatic(mods)) {
                    continue;
                }
                if (method.getName().equals(methodName) &&
                        method.getParameterTypes().length == parameterCount) {
                    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[] interfaces = initial.getInterfaces();
        for (int i = 0; i < interfaces.length; i++) {
            Method method = internalGetMethod(interfaces[i], methodName, parameterCount);
            if (method != null) {
                return method;
            }
        }

        return null;
    }

    /**
     * Find a method on a class with a specified number of parameters.
     */
    private static Method getMethod(Class clazz, String methodName, int parameterCount)
            throws IntrospectionException {
        if (methodName == null) {
            return null;
        }

        Method method = internalGetMethod(clazz, methodName, parameterCount);
        if (method != null) {
            return method;
        }

        // No Method found
        throw new IntrospectionException("No method \"" + methodName +
                "\" with " + parameterCount + " parameter(s)");
    }

    /**
     * Find a method on a class with a specified parameter list.
     */
    private static Method getMethod(Class clazz, String methodName, Class[] parameterTypes) 
                                           throws IntrospectionException {
        if (methodName == null) {
            return null;
        }

        Method method = MethodUtils.getMatchingAccessibleMethod(clazz, methodName, parameterTypes);
        if (method != null) {
            return method;
        }

        int parameterCount = (parameterTypes == null) ? 0 : parameterTypes.length;

        // No Method found
        throw new IntrospectionException("No method \"" + methodName +
                "\" with " + parameterCount + " parameter(s) of matching types.");
    }

}