liquibase.servicelocator

Class DefaultPackageScanClassResolver

java.lang.Object

liquibase.servicelocator.DefaultPackageScanClassResolver

All Implemented Interfaces:

PackageScanClassResolver

Direct Known Subclasses:

WebSpherePackageScanClassResolver

public class DefaultPackageScanClassResolver
extends java.lang.Object
implements PackageScanClassResolver

Default implement of PackageScanClassResolver

Field Summary

Fields

Modifier and Type	Field and Description
protected Logger	log

Constructor Summary

Constructors

Constructor and Description
DefaultPackageScanClassResolver()

Method Summary

Methods

Modifier and Type	Method and Description
void	addClassLoader(java.lang.ClassLoader classLoader) Adds the class loader to the existing loaders
void	addFilter(PackageScanFilter filter) Add a filter that will be applied to all scan operations
protected void	addIfMatching(PackageScanFilter test, java.lang.String fqn, java.util.Set<java.lang.Class<?>> classes) Add the class designated by the fully qualified class name provided to the set of resolved classes if and only if it is approved by the Test supplied.
protected java.net.URL	customResourceLocator(java.net.URL url)
protected void	find(PackageScanFilter test, java.lang.String packageName, java.lang.ClassLoader loader, java.util.Set<java.lang.Class<?>> classes)
protected void	find(PackageScanFilter test, java.lang.String packageName, java.util.Set<java.lang.Class<?>> classes)
java.util.Set<java.lang.Class<?>>	findByFilter(PackageScanFilter filter, java.lang.String... packageNames) Attempts to discover classes filter by the provided filter
java.util.Set<java.lang.Class<?>>	findImplementations(java.lang.Class parent, java.lang.String... packageNames) Attempts to discover classes that are assignable to the type provided.
java.util.Set<java.lang.ClassLoader>	getClassLoaders() Gets the ClassLoader instances that should be used when scanning for classes.
protected java.util.Enumeration<java.net.URL>	getResources(java.lang.ClassLoader loader, java.lang.String packageName) Strategy to get the resources by the given classloader.
protected void	loadImplementationsInJar(PackageScanFilter test, java.lang.String parent, java.io.InputStream stream, java.lang.String urlPath, java.util.Set<java.lang.Class<?>> classes) Finds matching classes within a jar files that contains a folder structure matching the package structure.
void	removeFilter(PackageScanFilter filter) Removes the filter
void	setClassLoaders(java.util.Set<java.lang.ClassLoader> classLoaders) Sets the ClassLoader instances that should be used when scanning for classes.

Methods inherited from class java.lang.Object

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

Field Detail

log

protected final transient Logger log

Constructor Detail

DefaultPackageScanClassResolver

public DefaultPackageScanClassResolver()

Method Detail

addClassLoader

public void addClassLoader(java.lang.ClassLoader classLoader)

Description copied from interface: PackageScanClassResolver

Adds the class loader to the existing loaders

Specified by:

addClassLoader in interface PackageScanClassResolver

Parameters:

classLoader - the loader to add

addFilter

public void addFilter(PackageScanFilter filter)

Description copied from interface: PackageScanClassResolver

Add a filter that will be applied to all scan operations

Specified by:

addFilter in interface PackageScanClassResolver

Parameters:

filter - filter to filter desired classes in all scan operations

removeFilter

public void removeFilter(PackageScanFilter filter)

Description copied from interface: PackageScanClassResolver

Removes the filter

Specified by:

removeFilter in interface PackageScanClassResolver

Parameters:

filter - filter to filter desired classes in all scan operations

getClassLoaders

public java.util.Set<java.lang.ClassLoader> getClassLoaders()

Description copied from interface: PackageScanClassResolver

Gets the ClassLoader instances that should be used when scanning for classes.

Specified by:

getClassLoaders in interface PackageScanClassResolver

Returns:

the class loaders to use

setClassLoaders

public void setClassLoaders(java.util.Set<java.lang.ClassLoader> classLoaders)

Description copied from interface: PackageScanClassResolver

Sets the ClassLoader instances that should be used when scanning for classes. If none is set then the context classloader will be used.

Specified by:

setClassLoaders in interface PackageScanClassResolver

Parameters:

classLoaders - loaders to use when scanning for classes

findImplementations

public java.util.Set<java.lang.Class<?>> findImplementations(java.lang.Class parent,
                                                    java.lang.String... packageNames)

Description copied from interface: PackageScanClassResolver

Attempts to discover classes that are assignable to the type provided. In the case that an interface is provided this method will collect implementations. In the case of a non-interface class, subclasses will be collected.

Specified by:

findImplementations in interface PackageScanClassResolver

Parameters:

parent - the class of interface to find subclasses or implementations of

packageNames - one or more package names to scan (including subpackages) for classes

Returns:

the classes found, returns an empty set if none found

findByFilter

public java.util.Set<java.lang.Class<?>> findByFilter(PackageScanFilter filter,
                                             java.lang.String... packageNames)

Description copied from interface: PackageScanClassResolver

Attempts to discover classes filter by the provided filter

Specified by:

findByFilter in interface PackageScanClassResolver

Parameters:

filter - filter to filter desired classes.

packageNames - one or more package names to scan (including subpackages) for classes

Returns:

the classes found, returns an empty set if none found

find

protected void find(PackageScanFilter test,
        java.lang.String packageName,
        java.util.Set<java.lang.Class<?>> classes)

find

protected void find(PackageScanFilter test,
        java.lang.String packageName,
        java.lang.ClassLoader loader,
        java.util.Set<java.lang.Class<?>> classes)

customResourceLocator

protected java.net.URL customResourceLocator(java.net.URL url)
                                      throws java.io.IOException

Throws:

java.io.IOException

getResources

protected java.util.Enumeration<java.net.URL> getResources(java.lang.ClassLoader loader,
                                               java.lang.String packageName)
                                                    throws java.io.IOException

Strategy to get the resources by the given classloader.

Notice that in WebSphere platforms there is a WebSpherePackageScanClassResolver to take care of WebSphere's odditiy of resource loading.

Parameters:

loader - the classloader

packageName - the packagename for the package to load

Returns:

URL's for the given package

Throws:

java.io.IOException - is thrown by the classloader

loadImplementationsInJar

protected void loadImplementationsInJar(PackageScanFilter test,
                            java.lang.String parent,
                            java.io.InputStream stream,
                            java.lang.String urlPath,
                            java.util.Set<java.lang.Class<?>> classes)

Finds matching classes within a jar files that contains a folder structure matching the package structure. If the File is not a JarFile or does not exist a warning will be logged, but no error will be raised.

Parameters:

test - a Test used to filter the classes that are discovered

parent - the parent package under which classes must be in order to be considered

stream - the inputstream of the jar file to be examined for classes

urlPath - the url of the jar file to be examined for classes

addIfMatching

protected void addIfMatching(PackageScanFilter test,
                 java.lang.String fqn,
                 java.util.Set<java.lang.Class<?>> classes)

Add the class designated by the fully qualified class name provided to the set of resolved classes if and only if it is approved by the Test supplied.

Parameters:

test - the test used to determine if the class matches

fqn - the fully qualified name of a class