This commits extends nullability declarations to the field level, formalizing the interaction between methods and their underlying fields and therefore avoiding any nullability mismatch.
Issue: SPR-15720
This commit also removes nullability from two common spots: ResolvableType.getType() and TargetSource.getTarget(), both of which are never effectively null with any regular implementation. For such scenarios, a non-null empty type/target is the cleaner contract.
Issue: SPR-15540
Beyond just formally declaring the current behavior, this revision actually enforces non-null behavior in selected signatures now, not tolerating null values anymore when not explicitly documented. It also changes some utility methods with historic null-in/null-out tolerance towards enforced non-null return values, making them a proper citizen in non-null assignments.
Some issues are left as to-do: in particular a thorough revision of spring-test, and a few tests with unclear failures (ignored as "TODO: NULLABLE") to be sorted out in a follow-up commit.
Issue: SPR-15540
This commit introduces 2 new @Nullable and @NonNullApi
annotations that leverage JSR 305 (dormant but available via
Findbugs jsr305 dependency and already used by libraries
like OkHttp) meta-annotations to specify explicitly
null-safety of Spring Framework parameters and return values.
In order to avoid adding too much annotations, the
default is set at package level with @NonNullApi and
@Nullable annotations are added when needed at parameter or
return value level. These annotations are intended to be used
on Spring Framework itself but also by other Spring projects.
@Nullable annotations have been introduced based on Javadoc
and search of patterns like "return null;". It is expected that
nullability of Spring Framework API will be polished with
complementary commits.
In practice, this will make the whole Spring Framework API
null-safe for Kotlin projects (when KT-10942 will be fixed)
since Kotlin will be able to leverage these annotations to
know if a parameter or a return value is nullable or not. But
this is also useful for Java developers as well since IntelliJ
IDEA, for example, also understands these annotations to
generate warnings when unsafe nullable usages are detected.
Issue: SPR-15540
This commit adds a test runtime dependency on log4j 2 for every project
and migrates all log4j.properties files to log4j2-test.xml files.
Issue: SPR-14431
This commit migrates all remaining tests from JUnit 3 to JUnit 4, with
the exception of Spring's legacy JUnit 3.8 based testing framework that
is still in use in the spring-orm module.
Issue: SPR-13514
While working on SPR-12532, an extra IdentityWrapper was added to work
around a backward compatible issue between commons pool 1.x and 2.x. This
issue (POOL-283) has actually been fixed in 2.4 and their IdentityWrapper
is using object equality so our wrapper is in the way.
Looking retrospectively, the code looks all fine without the workaround
and commons pool 2.4 or later so it has been removed.
`BeanWrapperImpl` and `DirectFieldAccessor` are two
`ConfigurablePropertyAccessor` implementations with different features
set.
This commit harmonizes the two implementations to use a common base class
that delegates the actual property handling to the sub-classes:
* `BeanWrapperImpl`: `PropertyDescriptor` and introspection utilities
* `DirectFieldAccessor`: reflection on `java.lang.Field`
Issues: SPR-12206 - SPR-12805
If a sub-class of Future (such as ListenableFuture) is used as a return
type and an exception is thrown, the AsyncUncaughtExceptionHandler is
called. Now checking for any Future implementation instead of a faulty
strict matching.
Issue: SPR-12797
Deprecated CommonsPoolTargetSource (supporting commons pool 1.5+) in
favor of CommonsPool2TargetSource with a similar contract.
Commons Pool 2.x uses object equality while Commons Pool 1.x used
identity equality. This clearly means that Commons Pool 2 behaves
differently if several instances having the same identity according to
their `Object#equals(Object)` method are managed in the same pool. To
provide a smooth upgrade, a backward-compatible pool is created by
default; use `setUseObjectEquality(boolean)` if you need the standard
Commons Pool 2.x behavior.
Issue: SPR-12532
Previously, if a bean has a scoped proxy and is annotated to be exposed
to the JMX domain, both the scoped proxy and the target instance were
exposed in the JMX domain, resulting in a duplicate entries. Worse, if
such bean defines an explicit name, the application wouldn't start
because of a name conflict.
This commit deals explicitely with scoped proxy and make sure to only
expose the relevant bean.
Issue: SPR-12529
Prior to this commit, only @Async annotated methods with proxy style
had their custom uncaught exception handler applied. This commit
harmonizes the configuration so that AspectJ applies that behaviour as
well.
Issue: SPR-12090
This commit adds the missing 4.1 XSDs for the following components:
* spring-aop
* spring-context
* spring-jee
* spring-lang
* spring-tx
* spring-util
These are strictly identical to the definition of the 4.0 XSDs.
Issue: SPR-11990
Prior to this commit, an exception thrown by an @Async void method
was not further processed as there is no way to transmit that
exception to the caller.
The AsyncUncaughtExceptionHandler is a new strategy interface that
can be implemented to handle unexpected exception thrown during the
invocation of such asynchronous method.
The handler can be specified using either the XML namespace or by
implementing the AsyncConfigurer interface with the EnableAsync
annotation.
Issue: SPR-8995
This commit rationalizes the use of @Order so that the standard
@Priority annotation can be used instead. The handling of both
annotations are now defined in OrderUtils.
This also updates the link to the JavaEE API so that we refer to
JavaEE7 instead of JavaEE6.
Issue: SPR-11639
Prior to this commit, the codebase was using a mix of log4j.xml
and log4j.properties for test-related logging configuration. This
can be an issue as log4j takes the xml variant first when looking
for a default bootstrap configuration.
In practice, some modules declaring the properties variant were
taking the xml variant configuration from another module.
The general structure of the configuration has also been
harmonized to provide a standard console output as well as an
easy way to enable trace logs for the current module.
- Consistent importing of org.junit.Assert.*;
- Proper declaration of expected exceptions via @Test(expected).
- Renamed SpEL ExpressionTestCase to AbstractExpressionTests.
- Formatting and test method naming conventions.
Fixed through downcasting to AspectJ's ReflectionType and ReflectionBasedReferenceTypeDelegate, obtaining the myClass field there. We only fall back to regular class loading if we encounter any other kind of type.
Issue: SPR-11344
(cherry picked from commit c406c56)
Fix a variety of typos throughout the project, primarily in
comments (javadoc or otherwise) but also in a handful of log messages
and a couple exception messages.
ISSUE: SPR-11123
Fix remaining Java compiler warnings, mainly around missing
generics or deprecated code.
Also add the `-Werror` compiler option to ensure that any future
warnings will fail the build.
Issue: SPR-11064
Extended DefaultAopProxyFactory to create Objenesis based proxies if the
library is on the classpath. This allows classes without a default
constructor being CGLib proxied. We're now falling back to original CGLib
based behavior in case the proxy creation using Objenesis fails.
Objenesis 2.0 is now inlined into spring-core to avoid interfering with
other Objenesis versions on the classpath.
Issue: SPR-10594
Also fixing an old XmlBeanFactory test that relies on "ref local" which is gone in the 4.0 xsd now, redeclaring the affected file to an older xsd version.
Also, StandardReflectionParameterNameDiscoverer calls "Parameter.isNamePresent()" now to return null (and pass on to the next discoverer) if no JDK 8 parameters are available. Note that this requires OpenJDK 8 b100 or higher to compile now.
Issue: SPR-10532
Removed spring-beans.dtd (the 1.x variant) and spring-oxm-1.5.xsd (pre-Spring-Framework variant), in order to raise the backwards compatibility limit a little bit at least. We'll keep supporting the 2.0 and 2.5 xsd versions for the time being, as well as spring-beans-2.0.dtd.
Removed the ref 'local' attribute in spring-beans-4.0.xsd since 'local' lost its differentiating role to a regular bean ref back in the 3.1 days when we started allowing for the same bean id to reappear in a different beans section of the same configuration file (with a different profile).
Issue: SPR-10437
* 3.2.x: (28 commits)
Hide 'doc' changes from jdiff reports
Document @Bean 'lite' mode vs @Configuration
Final preparations for 3.2.2
Remove Tiles 3 configuration method
Polishing
Extracted buildRequestAttributes template method from FrameworkServlet
Added "beforeExistingAdvisors" flag to AbstractAdvisingBeanPostProcessor
Minor refinements along the way of researching static CGLIB callbacks
Compare Kind references before checking log levels
Polish Javadoc in RequestAttributes
Fix copy-n-paste errors in NativeWebRequest
Fix issue with restoring included attributes
Add additional test for daylight savings glitch
Document context hierarchy support in the TCF
Fix test for daylight savings glitch
Make the methodParameter field of HandlerMethod final
Disable AsyncTests in spring-test-mvc
Reformat the testing chapter
Document context hierarchy support in the TCF
Document context hierarchy support in the TCF
...
Just AsyncAnnotationBeanPostProcessor switches "beforeExistingAdvisors" to "true" by default. So effectively, MethodValidation/PersistenceExceptionTranslationPostProcessor apply after existing advisors by default again, fixing the 3.1->3.2 regression.
Issue: SPR-10309
Assuming reference comparisons are much quicker than checking
likely-nested logger levels, perform the former first.
Also, since the reference can match only one of the instances,
use "else if" to short-circuit the search.
Prior to this commit many test utility classes and sample beans were
duplicated across projects. This was previously necessary due to the
fact that dependent test sources were not shared during a gradle
build. Since the introduction of the 'test-source-set-dependencies'
gradle plugin this is no longer the case.
This commit attempts to remove as much duplicate code as possible,
co-locating test utilities and beans in the most suitable project.
For example, test beans are now located in the 'spring-beans'
project.
Some of the duplicated code had started to drift apart when
modifications made in one project where not ported to others. All
changes have now been consolidated and when necessary existing tests
have been refactored to account for the differences.
Conflicts:
spring-beans/src/test/java/org/springframework/beans/factory/ConcurrentBeanFactoryTests.java
spring-beans/src/test/java/org/springframework/beans/factory/support/BeanFactoryGenericsTests.java
spring-beans/src/test/java/org/springframework/beans/support/PagedListHolderTests.java
* 3.2.x:
Exclude spring-build-src from maven publish
Move spring-build-junit into spring-core
Relocate MergePlugin package
Develop a gradle plugin to add test dependencies
Expose Gradle buildSrc for IDE support
Fix [deprecation] compiler warnings
Upgrade to xmlunit version 1.3
Improve 'build' folder ignores
Fix regression in static setter method support
Fix SpEL JavaBean compliance for setters
Conflicts:
spring-beans/src/test/java/org/springframework/beans/ExtendedBeanInfoTests.java
Move code from spring-build-junit into spring-core/src/test along with
several other test utility classes. This commit removes the temporary
spring-build-junit project introduced in commit
b083bbdec7.
Fix deprecation compiler warnings by refactoring code or applying
@SuppressWarnings("deprecation") annotations. JUnit tests of
internally deprecated classes are now themselves marked as
@Deprecated.
Numerous EasyMock deprecation warnings will remain until the
migration to mockito can be completed.
Fix serialization warnings by applying @SuppressWarnings("serial")
when appropriate.
In certain cases and for unknown reasons, a correctly-placed
@SuppressWarnings("serial") annotation will fix the warning at the
javac level (i.e. the Gradle command-line), but will produce an
"unnecessary @SuppressWarnings" warning within Eclipse. In these
cases, a private static final serialVersionUID field has been added
with the default value of 1L.
In particular, avoiding synchronized Sets and Maps wherever possible (preferring a ConcurrentHashMap even instead of a synchronized Set) and specifying appropriate ConcurrentHashMap initial capacities (even if we end up choosing 16).
- Support external Javadoc links using Gradle's javadoc.options.links
- Fix all other Javadoc warnings, such as typos, references to
non-existent (or no longer existent) types and members, etc,
including changes related to the Quartz 2.0 upgrade (SPR-8275) and
adding the HTTP PATCH method (SPR-7985).
- Suppress all output for project-level `javadoc` tasks in order to
hide false-negative warnings about cross-module @see and @link
references (e.g. spring-core having a @see reference to spring-web).
Use the `--info` (-i) flag to gradle at any time to see project-level
javadoc warnings without running the entire `api` task. e.g.
`gradle :spring-core:javadoc -i`
- Favor root project level `api` task for detection of legitimate
Javadoc warnings. There are now zero Javadoc warnings across the
entirety of spring-framework. Goal: keep it that way.
- Remove all @link and @see references to types and members that exist
only in Servlet <= 2.5 and Hibernate <= 4.0, favoring 3.0+ and 4.0+
respectively. This is necessary because only one version of each of
these dependencies can be present on the global `api` javadoc task's
classpath. To that end, the `api` task classpath has now been
customized to ensure that the Servlet 3 API and Hibernate Core 4 jars
have precedence.
- SPR-8896 replaced our dependency on aspectjrt with a dependency on
aspectjweaver, which is fine from a POM point of view, but causes
a spurious warning to be emitted from the ant iajc task that it
"cannot find aspectjrt on the classpath" - even though aspectjweaver
is perfectly sufficient. In the name of keeping the console quiet, a
new `rt` configuration has been added, and aspectjrt added as a
dependency to it. In turn, configurations.rt.asPath is appended to
the iajc classpath during both compileJava and compileTestJava for
spring-aspects.
Issue: SPR-10078, SPR-8275, SPR-7985, SPR-8896
Class#getDeclaredMembers returns arbitrary results under JDK7. This
results in non-deterministic execution of JUnit test methods, often
revealing unintended dependencies between methods that rely on a
specific order to succeed.
JUnit 4.11 contains support for predictable test ordering [1], but at
the time of this commit, JUnit 4.11 has not yet been released.
Therefore we are testing against a snapshot version [2], which has been
uploaded to repo.springsource.org [3] for easy access. Note that this
artifact may be removed when JUnit 4.11 goes GA.
- Care has been taken to ensure that spring-test's compile-time
dependency on JUnit remains at 4.10. This means that the spring-test
pom.xml will continue to have an optional <dependency> on JUnit
4.10, instead of the 4.11 snapshot.
- For reasons not fully understood, the upgrade to the 4.11 snapshot
of junit-dep caused NoSuchMethodErrors around certain Hamcrest
types, particularly CoreMatchers and Matchers. import statements
have been updated accordingly throughout affected test cases.
- Runtime errors also occurred around uses of JUnit @Rule and
ExpectedException. These have been reverted to use simpler
mechanisms like @Test(expected) in the meantime.
- Some test methods with order-based dependencies on one another have
been renamed in order to fall in line with JUnit 4.11's new method
ordering (as opposed to actually fixing the inter-test
dependencies). In other areas, the fix was as simple as adding a
tearDown method and cleaning up state.
- For no apparent reason, the timeout in AspectJAutoProxyCreatorTests'
testAspectsAndAdvisorNotAppliedToPrototypeIsFastEnough method begins
to be exceeded. Prior to this commit the timeout value was 3000 ms;
on the CI server under Linux/JDK6 and JDK7, the test begins taking
anywhere from 3500-5500 ms with this commit. It is presumed that
this is an incidental artifact of the upgrade to JUnit 4.11. In any
case, there are no changes to src/main in this commit, so this
should not actually represent a performance risk for Spring
Framework users. The timeout has been increased to 6000 ms to
accommodate this situation.
[1]: https://github.com/KentBeck/junit/pull/293
[2]: https://github.com/downloads/KentBeck/junit/junit-dep-4.11-SNAPSHOT-20120805-1225.jar
[3]: https://repo.springsource.org/simple/ext-release-local/junit/junit-dep/4.11.20120805.1225
Issue: SPR-9783
- Allow reset of GlobalAdvisorAdapterRegistry
Provide a reset() method allowing the GlobalAdvisorAdapterRegistry
instance to be replaced with a fresh instance. This method has
primarily been added to allow unit tests to leave the registry
in a known state.
- Protect against the fact that calls to configuration class methods
my occur in a random order.
Issue: SPR-9779
Update the ReflectiveAspectJAdvisorFactory class to sort candidate
AOP methods based on their annotation first and method name second.
Prior to this the order of aspects created from annotated methods
could differ depending on the underling JVM, as first noticed under
JDK7 in SPR-9729.
- ConvertingComparator and InstanceComparator have been introduced in
support of this change, per SPR-9730.
- A shared static INSTANCE field has been added to ComparableComparator
to avoid unnecessary instantiation costs within ConvertingComparator
as well as to prevent generics warnings during certain caller
scenarios.
Issue: SPR-9729, SPR-9730
CGLIB 3 has been released in order to depend on ASM 4, which Spring now
depends on internally (see previous commit).
This commit eliminates spring-beans' optional dependency on cglib-nodep
v2.2 and instead repackages net.sf.cglib => org.springframework.cglib
much in the same way we have historically done with ASM.
This change is beneficial to users in several ways:
- Eliminates the need to manually add CGLIB to the application
classpath; especially important for the growing number of
@Configuration class users. Java-based configuration functionality,
along with proxy-target-class and method injection features now
work 'out of the box' in Spring 3.2.
- Eliminates the possibility of conflicts with other libraries that
may dependend on differing versions of CGLIB, e.g. Hibernate
3.3.1.ga and its dependency on CGLIB 2.1.3 would easily cause a
conflict if the application were depending on CGLIB 3 for
Spring-related purposes.
- Picks up CGLIB 3's changes to support ASM 4, meaning that CGLIB is
that much less likely to work well in a Java 7 environment due to
ASM 4's support for transforming classes with invokedynamic
bytecode instructions.
On CGLIB and ASM:
CGLIB's own dependency on ASM is also transformed along the way to
depend on Spring's repackaged org.springframework.asm, primarily to
eliminate unnecessary duplication of ASM classfiles in spring-core and
in the process save around 100K in the final spring-core JAR file size.
It is coincidental that spring-core and CGLIB currently depend on the
exact same version of ASM (4.0), but it is also unlikely to change any
time soon. If this change does occur and versions of ASM drift, then
the size optimization mentioned above will have to be abandoned. This
would have no compatibility impact, however, so this is a reasonable
solution now and for the forseeable future.
On a mysterious NoClassDefFoundError:
During the upgrade to CGLIB 3.0, Spring test cases began failing due to
NoClassDefFoundErrors being thrown from CGLIB's DebuggingClassWriter
regarding its use of asm-util's TraceClassVisitor type. previous
versions of cglib-nodep, particularly 2.2, did not cause this behavior,
even though cglib-nodep has never actually repackaged and bundled
asm-util classes. The reason for these NoClassDefFoundErrors occurring
now is still not fully understood, but appears to be due to subtle JVM
bytecode preverification rules. The hypothesis is that due to minor
changes in DebuggingClassWriter such as additional casts, access to
instance variables declared in the superclass, and indeed a change in
the superclass hierarchy, preverification may be kicking in on the
toByteArray method body, at which point the reference to the missing
TraceClassVisitor type is noticed and the NCDFE is thrown. For this
reason, a dummy implementation of TraceClassVisitor has been added to
spring-core in the org.springframework.asm.util package. This class
simply ensures that Spring's own tests never result in the NCDFE
described above, and more importantly that Spring's users never
encounter the same.
Other changes include:
- rename package-private Cglib2AopProxy => CglibAopProxy
- eliminate all 'cglibAvailable' checks, warnings and errors
- eliminate all 'CGLIB2' language in favor of 'CGLIB'
- eliminate all mention in reference and java docs of needing to add
cglib(-nodep) to one's application classpath
Issue: SPR-9669
@Async executor qualification has been backported to 3.1.2. This commit
updates all @since tags appropriately, as well as carrying over the
changes backported to the spring-task-3.1 schema.
Issue: SPR-6847, SPR-9443
Commit 096693c46f refactored and
deprecated TransactionAspectUtils, moving its #qualifiedBeanOfType
and related methods into BeanFactoryUtils. This created a package cycle
between beans.factory and beans.factory.annotation due to use of the
beans.factory.annotation.Qualifier annotation in these methods.
This commit breaks the package cycle by introducing
beans.factory.annotation.BeanFactoryAnnotationUtils and moving these
@Qualifier-related methods to it. It is intentionally similar in name
and style to the familiar BeanFactoryUtils class for purposes of
discoverability.
There are no backward-compatibilty concerns associated with this change
as the cycle was introduced, caught and now fixed before a release.
Issue: SPR-6847
Prior to this change, Spring's @Async annotation support was tied to a
single AsyncTaskExecutor bean, meaning that all methods marked with
@Async were forced to use the same executor. This is an undesirable
limitation, given that certain methods may have different priorities,
etc. This leads to the need to (optionally) qualify which executor
should handle each method.
This is similar to the way that Spring's @Transactional annotation was
originally tied to a single PlatformTransactionManager, but in Spring
3.0 was enhanced to allow for a qualifier via the #value attribute, e.g.
@Transactional("ptm1")
public void m() { ... }
where "ptm1" is either the name of a PlatformTransactionManager bean or
a qualifier value associated with a PlatformTransactionManager bean,
e.g. via the <qualifier> element in XML or the @Qualifier annotation.
This commit introduces the same approach to @Async and its relationship
to underlying executor beans. As always, the following syntax remains
supported
@Async
public void m() { ... }
indicating that calls to #m will be delegated to the "default" executor,
i.e. the executor provided to
<task:annotation-driven executor="..."/>
or the executor specified when authoring a @Configuration class that
implements AsyncConfigurer and its #getAsyncExecutor method.
However, it now also possible to qualify which executor should be used
on a method-by-method basis, e.g.
@Async("e1")
public void m() { ... }
indicating that calls to #m will be delegated to the executor bean
named or otherwise qualified as "e1". Unlike the default executor
which is specified up front at configuration time as described above,
the "e1" executor bean is looked up within the container on the first
execution of #m and then cached in association with that method for the
lifetime of the container.
Class-level use of Async#value behaves as expected, indicating that all
methods within the annotated class should be executed with the named
executor. In the case of both method- and class-level annotations, any
method-level #value overrides any class level #value.
This commit introduces the following major changes:
- Add @Async#value attribute for executor qualification
- Introduce AsyncExecutionAspectSupport as a common base class for
both MethodInterceptor- and AspectJ-based async aspects. This base
class provides common structure for specifying the default executor
(#setExecutor) as well as logic for determining (and caching) which
executor should execute a given method (#determineAsyncExecutor) and
an abstract method to allow subclasses to provide specific strategies
for executor qualification (#getExecutorQualifier).
- Introduce AnnotationAsyncExecutionInterceptor as a specialization of
the existing AsyncExecutionInterceptor to allow for introspection of
the @Async annotation and its #value attribute for a given method.
Note that this new subclass was necessary for packaging reasons -
the original AsyncExecutionInterceptor lives in
org.springframework.aop and therefore does not have visibility to
the @Async annotation in org.springframework.scheduling.annotation.
This new subclass replaces usage of AsyncExecutionInterceptor
throughout the framework, though the latter remains usable and
undeprecated for compatibility with any existing third-party
extensions.
- Add documentation to spring-task-3.2.xsd and reference manual
explaining @Async executor qualification
- Add tests covering all new functionality
Note that the public API of all affected components remains backward-
compatible.
Issue: SPR-6847
In anticipation of substantive changes required to implement @Async
executor qualification, the following updates have been made to the
components and infrastructure supporting @Async functionality:
- Fix trailing whitespace and indentation errors
- Fix generics warnings
- Add Javadoc where missing, update to use {@code} tags, etc.
- Avoid NPE in AopUtils#canApply
- Organize imports to follow conventions
- Remove System.out.println statements from tests
- Correct various punctuation and grammar problems
This patch fixes several compiler warnings that do not point to code
problems. Two kinds of warnings are fixed. First in a lot of cases
@SuppressWarnings("unchecked") is used although there are no unchecked
casts happening. This seems to be a leftover from when the code base
was on Java 1.4, now that the code base was moved to Java 1.5 these are
no longer necessary. Secondly there some places where the raw types of
List and Class are used where there wildcard types (List<?> and
Class<?>) would work just as well without causing any raw type warnings.
These changes are beneficial particularly when working in Eclipse or
other IDEs because it reduces 'noise', helping to isolate actual
potential problems in the code.
The following changes have been made:
- remove @SuppressWarnings where no longer needed
- use wildcard types instead of raw types where possible
Before this change there were numerous javadoc warnings being reported
while building Spring framework API.
This commit resolves most of the javadoc warnings, reducing the total
number from 265 to 103.
Issue: SPR-9113
Copy spring-*-3.1.xsd => spring-*-3.2.xsd; this commit introduces no
substantive changes, but rather prepares for them by creating a clean
baseline. All internal references to 3.1 schemas (e.g. spring-tool) have
also been updated.
This renaming more intuitively expresses the relationship between
subprojects and the JAR artifacts they produce.
Tracking history across these renames is possible, but it requires
use of the --follow flag to `git log`, for example
$ git log spring-aop/src/main/java/org/springframework/aop/Advisor.java
will show history up until the renaming event, where
$ git log --follow spring-aop/src/main/java/org/springframework/aop/Advisor.java
will show history for all changes to the file, before and after the
renaming.
See http://chrisbeams.com/git-diff-across-renamed-directories