ThreadLocal-like class that keeps its value through Future.map/Future.flatMap is extremely useful to trace request, for example, for logging.
Is there existing abstraction in Scala library to serve as such Local?
Is there a way to attach such Local to ExecutionContext.global?
Here is a blog entry where someone describes using scala.util.DynamicVariable and a custom scala.concurrent.ExecutionContext to capture and manage it: http://stevenskelton.ca/threadlocal-variables-scala-futures/
And here's is another blog entry describing how Hootsuite does something similar: http://code.hootsuite.com/logging-contextual-info-in-an-asynchronous-scala-application/
Related
I am new to Doxygen but I want to use it for a technical documentation for our team.
The background: We have several services in .NET which are going to be called from a JAVA backend through RPC.
Therefore it is quite useful to have those services documented for the JAVA guys.
Using the Doxywizard did help in the first place, but it created a huge overflow of data, which I want to filter, but have no clue how to.
What I want to achieve is, that Doxygen ONLY will use methods, which does have a specific attribute.
For example:
[RpcMethod(id: "GetNumDemo", description: "A demo method")]
public async Task<int> GetNumDemo(JavaDTO dtoObject, int randNum)
I want to have the method within the documentation found by Doxygen since it has the RpcMethod attribute and also cause it have a JavaDTO object, I want to have this class documented as well.
But I am overwhelmed with it ... do you guys can help me? ... at least with a hint within the Doxygen documentation.
Read through the documentation and goodled
Data sly use is used for helper classes this could either be a Java WCMUsePojo or a server side Javascript .
How do I use a logger in a server side script eg. data-sly-use.nav="nav.js" ?
HTL comes with a set of global objects that are ready to be used in server side JS. One of these objects is the log object which exposes an implementation of org.slf4j.Logger
You can use it like the example below in your code:
log.info("some info");
More details can be found in the official documentation which also details out a lot of other helpful objects available in the same context.
In Paper [A Software Product Line for Static Analyses(2014)], there is an illustration related constructing call graph(Listing7).
In this example, Line14 is related to construct call graph. while i check the src code and API, what i could find is DefaultCHACallGraphDomain.scala which has no implementation of construct call graph.
As my purpose is using OPAL to construct call graph. Is there any demo or documents help me understanding existing CallGraphDomain in OPAL? currently, i can only find some class declaration.
I'll be really appreciated if anyone can give me some suggestions related this topic.
Thanks in advance.
Jiang
The interface that was shown in the paper doesn't exist anymore, so you can totally forget about it.
The default interface to get a CallGraph class is provided by the Project object you retrieve when you load the bytecode a Java project.
A general code Example:
val project = ... // a java project
val computedCallGraph = project.get(/* Some call graph key */)
val callGraph = computedCallGraph.callGraph // the final call graph interface.
The computed call graph contains several things. It contains the entry points, unresolved method calls, exceptions when something went wrong at the construction time and the actual call graph.
OPAL provides you several call graph algorithms, you can retrieve each by passing the corresponding call graph key to the Project's get method.
Currently, the following two keys are available and can be passed to Project.get (more information is available in the documentation of this classes):
CHACallGraphKey
VTACallGraphKey
Analysis mode - Library vs Application
To construct a valid call graph for a software project it depends on the project kind which analysis mode to chose. While applications provide complete information (except incomplete projects, class loading and so on), software libraries are intended to be used by other projects. However, those two different scenarios have to be kept in mind, when construction call graphs. More details can be found here: org.opalj.AnalysisModes
OPAL offers the following analysis modes:
DesktopApplication (safe for application call graphs)
LibraryWithClosePackagesAssumption (safe for call graphs that are used for security-insensitive analyses)
LibraryWithOpenPackagesAssumption (very conservative/safe for security analyses)
The analysis mode can be either configured in OPAL's config file or set as project setting at runtime. You can find the config file in the Common project under /src/main/resources/reference.conf.
All of those analysis modes are supported by the the CHACallGraphKey while VTACallGraphKey only supports applications so far.
NOTE: The interface may change in upcoming versions again.
I want to call the API of uima-text-segmenter https://code.google.com/p/uima-text-segmenter/source/browse/trunk/INSTALL?r=22 to run an example.
But I don`t know how to call the API...
the readme said,
With the DocumentAnalyzer, run the following descriptor
`desc/textSegmenter/wst-snowball-C99-JTextTilingAAE.xml` by taking the
uima-examples data as input.
Could anyone give me some code which could be run directly in main func for example?
Thanks a lot!
Long answer:
The link describes how you would set up the application from within the Eclipse UIMA environment. This sort of set-up is typically targeted at subject matter specialists with little or no coding experience. It allows them to work (relatively fast) with UIMA in a declarative way: all data structures and analysis engines (computing blocks within UIMA) are declared in xml (with a GUI on top of it), after which the framework takes care of the rest. In this scenario, you would typically run a UIMA pipeline using a run configuration from within Eclipse (or the included UIMA pipeline runner application). Luckily, UIMA allows you to do exactly the same from code, but I would recommend using UIMAFit (http://uima.apache.org/d/uimafit-current/tools.uimafit.book.html#d5e137) for this purpose instead of of UIMA, as it bundles lots of useful things and coding shortcuts.
Short answer:
Using UIMAFit, you can call Factory methods that create CollectionReader (read input), AnalysisEngine (process input) and Consumer objects (write/do other stuff) from (third-party provided) XML files. Use these methods to construct your pipeline and the SimplePipeline class to run it. To extract the data you need, you would manipulate the CAS object (containing your data) in a Consumer object, possibly with a callback. You could also do this in a Analysis Engine object. I recommend using DKPro's FeaturePathFactory (https://code.google.com/p/dkpro-core-asl/source/browse/de.tudarmstadt.ukp.dkpro.core-asl/trunk/de.tudarmstadt.ukp.dkpro.core.api.featurepath-asl/src/main/java/de/tudarmstadt/ukp/dkpro/core/api/featurepath/FeaturePathFactory.java?spec=svn1811&r=1811) to quickly access the feature you are after.
Code examples:
http://uima.apache.org/d/uimafit-current/tools.uimafit.book.html#d5e137 contains examples, but they all go in the opposite direction (class objects are used in the factory methods, instead of XML files - XML is generated from these classes). Take a look at the UIMAFit API to find the method you need, AnalysisEngineDescription from XML for example: http://uima.apache.org/d/uimafit-current/api/org/apache/uima/fit/factory/AnalysisEngineFactory.html#createEngineDescriptionFromPath-java.lang.String-java.lang.Object...-
I'm trying to access a data source that is defined within a web container (JBoss) from a fat client outside the container.
I've decided to look up the data source through JNDI. Actually, my persistence framework (Ibatis) does this.
When performing queries I always end up getting this error:
java.lang.IllegalAccessException: Method=public abstract java.sql.Connection java.sql.Statement.getConnection() throws java.sql.SQLException does not return Serializable
Stacktrace:
org.jboss.resource.adapter.jdbc.remote.WrapperDataSourceService.doStatementMethod(WrapperDataSourceS
ervice.java:411),
org.jboss.resource.adapter.jdbc.remote.WrapperDataSourceService.invoke(WrapperDataSourceService.java
:223),
sun.reflect.GeneratedMethodAccessor106.invoke(Unknown Source),
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25),
java.lang.reflect.Method.invoke(Method.java:585),
org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155),
org.jboss.mx.server.Invocation.dispatch(Invocation.java:94),
org.jboss.mx.server.Invocation.invoke(Invocation.java:86),
org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264),
org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659),
My Datasource:
<?xml version="1.0" encoding="UTF-8"?>
<datasources>
<local-tx-datasource>
<jndi-name>jdbc/xxxxxDS</jndi-name>
<connection-url>jdbc:oracle:thin:#xxxxxxxxx:1521:xxxxxxx</connection-url>
<use-java-context>false</use-java-context>
<driver-class>oracle.jdbc.driver.OracleDriver</driver-class>
<user-name>xxxxxxxx</user-name>
<password>xxxxxx</password>
<exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name>
<min-pool-size>5</min-pool-size>
<max-pool-size>20</max-pool-size>
</local-tx-datasource>
</datasources>
Does anyone have a clue where this could come from?
Maybe someone even knows a better way how to achieve this.
Any hints are much appreciated!
Cheers,
Michael
Not sure if this is the same issue?
JBoss DataSource config
DataSource wrappers are not usable outside of the server VM
#Michael Well, java.sql.Connection is an Interface - it might technically be possible for the concrete implementation you're getting from JBoss to be Serializable - but I don't think you're really going to have any options you can use. If it was possible, it would probably be easy :)
I think #toolkit might have said the right words with useable outside the VM - the JDBC drivers will be talking to native driver code running in the underlying OS I guess, so that might explain why you can't just pass a connection over the network elsewhere.
My advice, (if you don't get any better advice!) would be to find a different approach - if you have access to locate the resource on the JBoss directory, maybe implement a proxy object that you can locate and obtain from the directory that allows you to use the connection remotely from your fat client. That's a design pattern called data transfer object I think Wikipedia entry
#toolkit:
Well, not exactly. Since I can access the data source over JNDI, it is actually visible and thus usable.
Or am I getting something totally wrong?
#Brabster:
I think you're on the right track. Isn't there a way to make the connection serializable? Maybe it's just a configuration issue...
I've read up on Ibatis now - maybe you can make your implementations of Dao etc. Serializable, post them into your directory and so retrieve them and use them in your fat client? You'd get reuse benefits out of that too.
Here's an example of something looks similar for Wicket
JBoss wraps up all DataSources with it's own ones.
That lets it play tricks with autocommit to get the specified J2EE behaviour out of a JDBC connection. They are mostly serailizable. But you needn't trust them.
I'd look carefully at it's wrappers. I've written a surrogate for JBoss's J2EE wrappers wrapper for JDBC that works with OOCJNDI to get my DAO code unit test-able standalone.
You just wrap java.sql.Driver, point OOCJNDI at your class, and run in JUnit.
The Driver wrapper can just directly create a SQL Driver and delegate to it.
Return a java.sql.Connection wrapper of your own devising on Connect.
A ConnectionWrapper can just wrap the Connection your Oracle driver gives you,
and all it does special is set Autocommit true.
Don't forget Eclipse can wrt delgates for you. Add a member you need to delegate to , then select it and right click, source -=>add delgage methods.
This is great when you get paid by the line ;-)
Bada-bing, Bada-boom, JUnit out of the box J2EE testing.
Your problem is probably amenable to the same thing, with JUnit crossed out and FatCLient written in an crayon.
My FatClient uses RMI generated with xdoclet to talk to the J2EE server, so I don't have your problem.
I think the exception indicates that the SQLConnection object you're trying to retrieve doesn't implement the Serializable interface, so it can't be passed to you the way you asked for it.
From the limited work I've done with JDNI, if you're asking for an object via JNDI it must be serializable. As far as I know, there's no way round that - if I think of a better way I'll post it up...
OK, one obvious option is to provide a serializable object local to the datasource that uses it but doesn't have the datasource as part of its serializable object graph. The fat client could then look up that object and query it instead.
Or create a (web?) service through which to access the datasource is governed - again your fat client would hit the service - this would probably be better encapsulated and more reuseable approach if those are concerns for you.