org.apache.wiki.util

Class ClassUtil

java.lang.Object

org.apache.wiki.util.ClassUtil

public final class ClassUtil
extends java.lang.Object

Contains useful utilities for class file manipulation. This is a static class, so there is no need to instantiate it.

Since:

2.1.29.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	MAPPINGS The location of the classmappings.xml document.
static java.lang.String	MAPPINGS_EXTRA The location of the classmappings-extra.xml document.

Method Summary

Modifier and Type	Method and Description
static boolean	assignable(java.lang.String srcClassName, java.lang.String parentClassName) checks if srcClassName is a subclass of parentClassname.
static <T> T	buildInstance(java.lang.Class<T> from) This method is used to instantiate a given class.
static <T> T	buildInstance(java.lang.Class<T> from, java.lang.Object... initArgs) This method is used to instantiate a given class.
static <T> T	buildInstance(java.lang.String className) This method is used to instantiate a given class.
static <T> T	buildInstance(java.lang.String packageName, java.lang.String className) This method is used to instantiate a given class.
static java.util.List<java.lang.String>	classpathEntriesUnder(java.lang.String rootPackage) Lists all the files in classpath under a given package.
static boolean	exists(java.lang.String className) Checks if a given class exists in classpath.
static <T> java.lang.Class<T>	findClass(java.util.List<java.lang.String> packages, java.util.List<java.lang.String> externaljars, java.lang.String className) Attempts to find a class from a collection of packages.
static <T> java.lang.Class<T>	findClass(java.lang.String packageName, java.lang.String className) It will first attempt to instantiate the class directly from the className, and will then try to prefix it with the packageName.
static java.util.Map<java.lang.String,java.lang.String>	getExtraClassMappings()
static java.lang.Class<?>	getMappedClass(java.lang.String requestedClass) Finds a mapped class from the c_classMappings list.
static <T> T	getMappedObject(java.lang.String requestedClass) This method is used to locate and instantiate a mapped class.
static <T> T	getMappedObject(java.lang.String requestedClass, java.lang.Object... initargs) This method is used to locate and instantiate a mapped class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAPPINGS

public static final java.lang.String MAPPINGS

The location of the classmappings.xml document. It will be searched for in the classpath. Its value is ""ini/classmappings.xml"".

See Also:

Constant Field Values

MAPPINGS_EXTRA

public static final java.lang.String MAPPINGS_EXTRA

The location of the classmappings-extra.xml document. It will be searched for in the classpath. Its value is ""ini/classmappings-extra.xml"".

See Also:

Constant Field Values

Method Detail

findClass

public static <T> java.lang.Class<T> findClass(java.util.List<java.lang.String> packages,
                                               java.util.List<java.lang.String> externaljars,
                                               java.lang.String className)
                                        throws java.lang.ClassNotFoundException

Attempts to find a class from a collection of packages. This will first attempt to find the class based on just the className parameter, but should that fail, will iterate through the "packages" -list, prefixes the package name to the className, and then tries to find the class again.

Parameters:

packages - A List of Strings, containing different package names.

className - The name of the class to find.

Returns:

The class, if it was found.

Throws:

java.lang.ClassNotFoundException - if this particular class cannot be found from the list.

findClass

public static <T> java.lang.Class<T> findClass(java.lang.String packageName,
                                               java.lang.String className)
                                        throws java.lang.ClassNotFoundException

It will first attempt to instantiate the class directly from the className, and will then try to prefix it with the packageName.

Parameters:

packageName - A package name (such as "org.apache.wiki.plugins").

className - The class name to find.

Returns:

The class, if it was found.

Throws:

java.lang.ClassNotFoundException - if this particular class cannot be found.

classpathEntriesUnder

public static java.util.List<java.lang.String> classpathEntriesUnder(java.lang.String rootPackage)

Lists all the files in classpath under a given package.

Parameters:

rootPackage - the base package. Can be {code null}.

Returns:

all files entries in classpath under the given package

getMappedObject

public static <T> T getMappedObject(java.lang.String requestedClass)
                             throws java.lang.ReflectiveOperationException,
                                    java.lang.IllegalArgumentException

This method is used to locate and instantiate a mapped class. You may redefine anything in the resource file which is located in your classpath under the name ClassUtil.MAPPINGS ("ini/classmappings.xml").

This is an extremely powerful system, which allows you to remap many of the JSPWiki core classes to your own class. Please read the documentation included in the default "ini/classmappings.xml" file to see how this method works.

Parameters:

requestedClass - The name of the class you wish to instantiate.

Returns:

An instantiated Object.

Throws:

java.lang.IllegalArgumentException - If the class cannot be found or instantiated.

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.5.40

getMappedObject

public static <T> T getMappedObject(java.lang.String requestedClass,
                                    java.lang.Object... initargs)
                             throws java.lang.ReflectiveOperationException,
                                    java.lang.IllegalArgumentException

This method is used to locate and instantiate a mapped class. You may redefine anything in the resource file which is located in your classpath under the name "ini/classmappings.xml".

This is an extremely powerful system, which allows you to remap many of the JSPWiki core classes to your own class. Please read the documentation included in the default "ini/classmappings.xml" file to see how this method works.

This method takes in an object array for the constructor arguments for classes which have more than two constructors.

Parameters:

requestedClass - The name of the class you wish to instantiate.

initargs - The parameters to be passed to the constructor. May be null.

Returns:

An instantiated Object.

Throws:

java.lang.IllegalArgumentException - If the class cannot be found or instantiated.

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.5.40

getMappedClass

public static java.lang.Class<?> getMappedClass(java.lang.String requestedClass)
                                         throws java.lang.ClassNotFoundException

Finds a mapped class from the c_classMappings list. If there is no mappped class, will use the requestedClass.

Parameters:

requestedClass - requested class.

Returns:

A Class object which you can then instantiate.

Throws:

java.lang.ClassNotFoundException - if the class is not found.

assignable

public static boolean assignable(java.lang.String srcClassName,
                                 java.lang.String parentClassName)

checks if srcClassName is a subclass of parentClassname.

Parameters:

srcClassName - expected subclass.

parentClassName - expected parent class.

Returns:

true if srcClassName is a subclass of parentClassname, false otherwise.

exists

public static boolean exists(java.lang.String className)

Checks if a given class exists in classpath.

Parameters:

className - the class to check for existence.

Returns:

true if it exists, false otherwise.

getExtraClassMappings

public static java.util.Map<java.lang.String,java.lang.String> getExtraClassMappings()

buildInstance

public static <T> T buildInstance(java.lang.String className)
                           throws java.lang.ReflectiveOperationException

This method is used to instantiate a given class.

Parameters:

className - The name of the class you wish to instantiate.

Returns:

An instantiated Object.

Throws:

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.11.1

buildInstance

public static <T> T buildInstance(java.lang.String packageName,
                                  java.lang.String className)
                           throws java.lang.ReflectiveOperationException

This method is used to instantiate a given class.

* It will first attempt to instantiate the class directly from the className, and will then try to prefix it with the packageName.

Parameters:

packageName - A package name (such as "org.apache.wiki.plugins").

className - The class name to find.

Returns:

An instantiated Object.

Throws:

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.11.1

buildInstance

public static <T> T buildInstance(java.lang.Class<T> from)
                           throws java.lang.ReflectiveOperationException

This method is used to instantiate a given class.

Parameters:

from - The name of the class you wish to instantiate.

Returns:

An instantiated Object.

Throws:

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.11.1

buildInstance

public static <T> T buildInstance(java.lang.Class<T> from,
                                  java.lang.Object... initArgs)
                           throws java.lang.ReflectiveOperationException

This method is used to instantiate a given class.

This method takes in an object array for the constructor arguments for classes which have more than two constructors.

Parameters:

from - The name of the class you wish to instantiate.

initArgs - The parameters to be passed to the constructor. May be null.

Returns:

An instantiated Object.

Throws:

java.lang.ReflectiveOperationException - If the class cannot be found or instantiated.

Since:

2.11.1