| java.lang.Object
 java.beans.Introspector
| Introspector | | public class Introspector (Code) | | The Introspector class provides a standard way for tools to learn about
the properties, events, and methods supported by a target Java Bean.
For each of those three kinds of information, the Introspector will
separately analyze the bean's class and superclasses looking for
either explicit or implicit information and use that information to
build a BeanInfo object that comprehensively describes the target bean.
For each class "Foo", explicit information may be available if there exists
a corresponding "FooBeanInfo" class that provides a non-null value when
queried for the information. We first look for the BeanInfo class by
taking the full package-qualified name of the target bean class and
appending "BeanInfo" to form a new class name. If this fails, then
we take the final classname component of this name, and look for that
class in each of the packages specified in the BeanInfo package search
path.
Thus for a class such as "sun.xyz.OurButton" we would first look for a
BeanInfo class called "sun.xyz.OurButtonBeanInfo" and if that failed we'd
look in each package in the BeanInfo search path for an OurButtonBeanInfo
class. With the default search path, this would mean looking for
"sun.beans.infos.OurButtonBeanInfo".
If a class provides explicit BeanInfo about itself then we add that to
the BeanInfo information we obtained from analyzing any derived classes,
but we regard the explicit information as being definitive for the current
class and its base classes, and do not proceed any further up the superclass
chain.
If we don't find explicit BeanInfo on a class, we use low-level
reflection to study the methods of the class and apply standard design
patterns to identify property accessors, event sources, or public
methods. We then proceed to analyze the class's superclass and add
in the information from it (and possibly on up the superclass chain).
Because the Introspector caches BeanInfo classes for better performance,
take care if you use it in an application that uses
multiple class loaders.
In general, when you destroy a ClassLoader
that has been used to introspect classes,
you should use the
Introspector.flushCaches Introspector.flushCaches
or
Introspector.flushFromCaches Introspector.flushFromCaches method
to flush all of the introspected classes out of the cache.
For more information about introspection and design patterns, please
consult the
JavaBeans specification.
|
| Method Summary | |
| public static String | decapitalize(String name)
Utility method to take a string and convert it to normal Java variable
name capitalization. | | static Method | findMethod(Class cls, String methodName, int argCount)
Find a target methodName on a given class. | | static Method | findMethod(Class cls, String methodName, int argCount, Class args)
Find a target methodName with specific parameter list on a given class.
Used in the contructors of the EventSetDescriptor,
PropertyDescriptor and the IndexedPropertyDescriptor.
Parameters:
cls - The Class object on which to retrieve the method.
Parameters:
methodName - Name of the method.
Parameters:
argCount - Number of arguments for the desired method.
Parameters:
args - Array of argument types for the method. | | public static void | flushCaches()
Flush all of the Introspector's internal caches. | | public static void | flushFromCaches(Class clz)
Flush the Introspector's internal cached information for a given class.
This method is not normally required. | | public static BeanInfo | getBeanInfo(Class beanClass)
Introspect on a Java Bean and learn about all its properties, exposed
methods, and events.
If the BeanInfo class for a Java Bean has been previously Introspected
then the BeanInfo class is retrieved from the BeanInfo cache.
Parameters:
beanClass - The bean class to be analyzed. | | public static BeanInfo | getBeanInfo(Class beanClass, int flags)
Introspect on a Java bean and learn about all its properties, exposed
methods, and events, subject to some control flags.
If the BeanInfo class for a Java Bean has been previously Introspected
based on the same arguments then the BeanInfo class is retrieved
from the BeanInfo cache.
Parameters:
beanClass - The bean class to be analyzed.
Parameters:
flags - Flags to control the introspection.If flags == USE_ALL_BEANINFO then we use all of the BeanInfoclasses we can discover.If flags == IGNORE_IMMEDIATE_BEANINFO then we ignore anyBeanInfo associated with the specified beanClass.If flags == IGNORE_ALL_BEANINFO then we ignore all BeanInfoassociated with the specified beanClass or any of itsparent classes. | | public static BeanInfo | getBeanInfo(Class beanClass, Class stopClass)
Introspect on a Java bean and learn all about its properties, exposed
methods, below a given "stop" point.
If the BeanInfo class for a Java Bean has been previously Introspected
based on the same arguments, then the BeanInfo class is retrieved
from the BeanInfo cache.
Parameters:
beanClass - The bean class to be analyzed.
Parameters:
stopClass - The baseclass at which to stop the analysis. | | public static synchronized String[] | getBeanInfoSearchPath()
Gets the list of package names that will be used for
finding BeanInfo classes.
The array of package names that will be searched inorder to find BeanInfo classes. | | static Object | instantiate(Class sibling, String className)
Try to create an instance of a named class. | | static boolean | isSubclass(Class a, Class b)
Return true if class a is either equivalent to class b, or
if class a is a subclass of class b, i.e. | | public static synchronized void | setBeanInfoSearchPath(String path)
Change the list of package names that will be used for
finding BeanInfo classes. |
| IGNORE_ALL_BEANINFO | | final public static int IGNORE_ALL_BEANINFO(Code) | | |
| IGNORE_IMMEDIATE_BEANINFO | | final public static int IGNORE_IMMEDIATE_BEANINFO(Code) | | |
| USE_ALL_BEANINFO | | final public static int USE_ALL_BEANINFO(Code) | | |
| decapitalize | | public static String decapitalize(String name)(Code) | | Utility method to take a string and convert it to normal Java variable
name capitalization. This normally means converting the first
character from upper case to lower case, but in the (unusual) special
case when there is more than one character and both the first and
second characters are upper case, we leave it alone.
Thus "FooBah" becomes "fooBah" and "X" becomes "x", but "URL" stays
as "URL".
Parameters:
name - The string to be decapitalized. The decapitalized version of the string. |
| findMethod | | static Method findMethod(Class cls, String methodName, int argCount)(Code) | | Find a target methodName on a given class.
|
| findMethod | | static Method findMethod(Class cls, String methodName, int argCount, Class args)(Code) | | Find a target methodName with specific parameter list on a given class.
Used in the contructors of the EventSetDescriptor,
PropertyDescriptor and the IndexedPropertyDescriptor.
Parameters:
cls - The Class object on which to retrieve the method.
Parameters:
methodName - Name of the method.
Parameters:
argCount - Number of arguments for the desired method.
Parameters:
args - Array of argument types for the method. the method or null if not found |
| flushCaches | | public static void flushCaches()(Code) | | Flush all of the Introspector's internal caches. This method is
not normally required. It is normally only needed by advanced
tools that update existing "Class" objects in-place and need
to make the Introspector re-analyze existing Class objects.
|
| flushFromCaches | | public static void flushFromCaches(Class clz)(Code) | | Flush the Introspector's internal cached information for a given class.
This method is not normally required. It is normally only needed
by advanced tools that update existing "Class" objects in-place
and need to make the Introspector re-analyze an existing Class object.
Note that only the direct state associated with the target Class
object is flushed. We do not flush state for other Class objects
with the same name, nor do we flush state for any related Class
objects (such as subclasses), even though their state may include
information indirectly obtained from the target Class object.
Parameters:
clz - Class object to be flushed.
throws:
NullPointerException - If the Class object is null. |
| getBeanInfo | | public static BeanInfo getBeanInfo(Class beanClass, int flags) throws IntrospectionException(Code) | | Introspect on a Java bean and learn about all its properties, exposed
methods, and events, subject to some control flags.
If the BeanInfo class for a Java Bean has been previously Introspected
based on the same arguments then the BeanInfo class is retrieved
from the BeanInfo cache.
Parameters:
beanClass - The bean class to be analyzed.
Parameters:
flags - Flags to control the introspection.If flags == USE_ALL_BEANINFO then we use all of the BeanInfoclasses we can discover.If flags == IGNORE_IMMEDIATE_BEANINFO then we ignore anyBeanInfo associated with the specified beanClass.If flags == IGNORE_ALL_BEANINFO then we ignore all BeanInfoassociated with the specified beanClass or any of itsparent classes. A BeanInfo object describing the target bean.
exception:
IntrospectionException - if an exception occurs duringintrospection. |
| getBeanInfo | | public static BeanInfo getBeanInfo(Class beanClass, Class stopClass) throws IntrospectionException(Code) | | Introspect on a Java bean and learn all about its properties, exposed
methods, below a given "stop" point.
If the BeanInfo class for a Java Bean has been previously Introspected
based on the same arguments, then the BeanInfo class is retrieved
from the BeanInfo cache.
Parameters:
beanClass - The bean class to be analyzed.
Parameters:
stopClass - The baseclass at which to stop the analysis. Anymethods/properties/events in the stopClass or in its baseclasseswill be ignored in the analysis.
exception:
IntrospectionException - if an exception occurs duringintrospection. |
| getBeanInfoSearchPath | | public static synchronized String[] getBeanInfoSearchPath()(Code) | | Gets the list of package names that will be used for
finding BeanInfo classes.
The array of package names that will be searched inorder to find BeanInfo classes. The default valuefor this array is implementation-dependent; e.g. Sun implementation initially sets to {"sun.beans.infos"}. |
| isSubclass | | static boolean isSubclass(Class a, Class b)(Code) | | Return true if class a is either equivalent to class b, or
if class a is a subclass of class b, i.e. if a either "extends"
or "implements" b.
Note tht either or both "Class" objects may represent interfaces.
|
| setBeanInfoSearchPath | | public static synchronized void setBeanInfoSearchPath(String path)(Code) | | Change the list of package names that will be used for
finding BeanInfo classes. The behaviour of
this method is undefined if parameter path
is null.
First, if there is a security manager, its checkPropertiesAccess
method is called. This could result in a SecurityException.
Parameters:
path - Array of package names.
exception:
SecurityException - if a security manager exists and its checkPropertiesAccess method doesn't allow settingof system properties.
See Also: SecurityManager.checkPropertiesAccess |
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