org.apache.commons.jexl3.internal.introspection
Class Introspector

java.lang.Object
  org.apache.commons.jexl3.internal.introspection.Introspector

public final class Introspector
extends Object

This basic function of this class is to return a Method object for a particular class given the name of a method and the parameters to the method in the form of an Object[].

The first time the Introspector sees a class it creates a class method map for the class in question. Basically the class method map is a Hashtable where Method objects are keyed by the aggregation of the method name and the array of parameters classes. This mapping is performed for all the public methods of a class and stored.

Since:

1.0

rlog

protected final org.apache.commons.logging.Log rlog

the logger.

Introspector

public Introspector(org.apache.commons.logging.Log log,
                    ClassLoader cloader)

Create the introspector.

Parameters:

log - the logger to use

cloader - the class loader

getClassByName

public Class<?> getClassByName(String className)

Gets a class by name through this introspector class loader.

Parameters:

className - the class name

Returns:

the class instance or null if it could not be found

getMethod

public Method getMethod(Class<?> c,
                        String name,
                        Object[] params)

Gets a method defined by a class, a name and a set of parameters.

Parameters:

c - the class

name - the method name

params - the method parameters

Returns:

the desired method object

Throws:

MethodKey.AmbiguousException - if no unambiguous method could be found through introspection

getMethod

public Method getMethod(Class<?> c,
                        MethodKey key)

Gets the method defined by the MethodKey for the class c.

Parameters:

c - Class in which the method search is taking place

key - Key of the method being searched for

Returns:

The desired method object

Throws:

MethodKey.AmbiguousException - if no unambiguous method could be found through introspection

getField

public Field getField(Class<?> c,
                      String key)

Gets the field named by key for the class c.

Parameters:

c - Class in which the field search is taking place

key - Name of the field being searched for

Returns:

the desired field or null if it does not exist or is not accessible

getFieldNames

public String[] getFieldNames(Class<?> c)

Gets the array of accessible field names known for a given class.

Parameters:

c - the class

Returns:

the class field names

getMethodNames

public String[] getMethodNames(Class<?> c)

Gets the array of accessible methods names known for a given class.

Parameters:

c - the class

Returns:

the class method names

getMethods

public Method[] getMethods(Class<?> c,
                           String methodName)

Gets the array of accessible method known for a given class.

Parameters:

c - the class

methodName - the method name

Returns:

the array of methods (null or not empty)

getConstructor

public Constructor<?> getConstructor(MethodKey key)

Gets the constructor defined by the MethodKey.

Parameters:

key - Key of the constructor being searched for

Returns:

The desired constructor object or null if no unambiguous constructor could be found through introspection.

getConstructor

public Constructor<?> getConstructor(Class<?> c,
                                     MethodKey key)

Gets the constructor defined by the MethodKey.

Parameters:

c - the class we want to instantiate

key - Key of the constructor being searched for

Returns:

The desired constructor object or null if no unambiguous constructor could be found through introspection.

setLoader

public void setLoader(ClassLoader cloader)

Sets the class loader used to solve constructors.

Also cleans the constructors and methods caches.

Parameters:

cloader - the class loader; if null, use this instance class loader

getLoader

public ClassLoader getLoader()

Gets the class loader used by this introspector.

Returns:

the class loader