How to automatically generate lexer+parser with ANTLR4 and Maven? - eclipse

I'am new to ANTLR4, and it seems that there is no Eclipse-Plug-In for v4. So it would nice to build automatically the Java sources from the .g4 grammars. I have a simple, empty Maven-project with src/main/java, src/test/java. Where to place the .g4 files? How can I automatically build the grammars with Maven?
My own POM-test failed:
<repository>
<id>mvn-public</id>
<name>MVNRepository</name>
<url>http://mvnrepository.com</url>
</repository>
...
<build>
<plugins>
<plugin>
<groupId>org.antlr</groupId>
<artifactId>antlr4-maven-plugin</artifactId>
<version>4.0.0</version>
<executions>
<execution>
<goals>
<goal>antlr</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Eclipse says:
Failure to find org.antlr:antlr4-maven-plugin:pom:4.0.0 in http://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of
central has elapsed or updates are forced

I created the following Gist with a pom.xml designed solely for supporting automatic code generation from ANTLR 4 grammars during an Eclipse build. It includes the necessary lifecycle information for m2e to know that the code generation is necessary, and explicitly adds the code generation folder using the build-helper-maven-plugin since Eclipse seemed to have some trouble locating it otherwise.
In this configuration, grammar files (*.g4) are placed alongside the other Java source files. The Maven plugin will automatically add the proper package ... statement to the generated files, so you shouldn't include a #header{package ...} line in the grammar itself.
https://gist.github.com/sharwell/4979017

Check out this Antlr4 plugin for Eclipse
https://github.com/jknack/antlr4ide

Related

Eclipse overwrites manifest created by maven bundle plugin

I'm using maven-bundle-plugin to generate MANIFEST.MF for OSGi container.
<build>
<plugins>
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId>
<extensions>true</extensions>
<configuration>
<instructions>
<Export-Package>com.example.mypackage</Export-Package>
</instructions>
</configuration>
<executions>
<execution>
<id>bundle-manifest</id>
<phase>process-classes</phase>
<goals>
<goal>manifest</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
However, that manifest file got destroyed (overwritten) by Eclipse (4.6.1 Neon) after, f.g Maven/Update Project or Clean/Build.
Is it possible to make Eclipse somehow aware of the maven plugins, and not destroy their output? What should I setup to prevent that (mis)behaviour?
If that issue is not to be fixed with Eclipse, does it work better with IntelliJ, for example? OSGi support within IDE is quite important for me...
I have to change my answer. I missed the part that you define the goal manifest. This is the new and recommended way to use the maven bundle plguin but it requires that you tell the jar plugin to use the existing Manifest.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.5</version>
<configuration>
<archive>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
</archive>
</configuration>
</plugin>
old answer
I suspect you are using the Eclipse PDE. The PDE is always working Manifest first. This means it is incompatible with the maven-bundle-plugin.
I recommend to use a plain maven build which we use a lot at apache projects like Apache Karaf or Apache Aries. It lacks the special OSGi support of Eclipse PDE but this sucks anyway.
You can augment this by using the eclipse plugin bndtools. Bndtools now provides maven support to a degree. This means you can now provide maven based OBR indexes for your project and define which bundles to start in a bndrun file. This allows to directly start and debug your OSGi project in Eclipse. See the osgi-chat example on how to do it.
Beware though that bndtools just started with maven support recently. So the current version 3.3.0 still lacks some of the convenience for maven builds.
With my configuration:
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId>
<version>3.3.0</version>
<extensions>true</extensions>
<configuration>
<manifestLocation>src/main/resources/META-INF</manifestLocation>
<rebuildBundle>true</rebuildBundle>
<instructions>
<Bundle-SymbolicName>${project.artifactId};singleton:=true</Bundle-SymbolicName>
</instructions>
</configuration>
</plugin>
And the Plugins installed:
m2e Connector: http://download.eclipse.org/m2e-wtp/releases/neon/
BND Tools: http://bndtools.org/
The Eclipse build finally didn't destroy the manifest file. But there were some iterations(maven build, Update Maven Dependencies, Eclipse Build, maven build) necessary. Also beforehand, I deleted all project related settings on the filesystem: .classpath, .project, .factorypath, .settings, .apt_generated, target. Hope that helps.

Eclipse javadoc: The type package-info is already defined

OS: Windows 7 x64
Eclipse Platform: 3.7.2.M20120208
m2e: 1.0.200.20111228-1245
Have similar problem as in this bug.
There is a bunch of package-info.java files in /src and /test folders, so they have same package. Eclipse show error:
"The type **package-info** is already defined"
I can delete package-info.java files either in /test or /src to avoid problem indication. But this workaround is not very comfort since I am using SCM and need to delete this files all time after update.
Same for Eclipse Platform 4.2.0.I20120608-1400
You can do this -->
Go to Build path -> configure build path -->
in Source tab -->
select the package (in which you have these problematic package-info.java file)
for eg. project-name/src/test/java
click on exclude -> and in exclusion pattern add "**/package-info.java"
this should solve the problem, as plainly you are asking eclipse to exclude these files, and thus you wouldn't have to delete those files and solving your SCM related issues
There are a few options to solve this:
Move away from package-info.java files, and replace them with package.html files.
Only have package-info.java files in the src/ tree, as the same-named packages in the test/ tree will "overlap" the src/ tree.
Generate javadoc separately for the src/ and test/ trees, as they are probably for different audiences.
If you use maven and m2e for interaction between eclipse and maven. There is a quite clean solution: add a profile to pom.xml that is activated only by m2e and prevents compilation of package-info.java in the test-compile phase. Here a sample :
<profile>
<id>m2e</id><!--This profile is activated when eclipse interacts with maven (using m2e).-->
<activation>
<property>
<name>m2e.version</name>
</property>
</activation>
<build>
<plugins>
<plugin>
<!--eclipse do not support duplicated package-info.java, in both src and test.-->
<artifactId>maven-compiler-plugin</artifactId>
<executions>
<execution>
<id>default-testCompile</id>
<phase>test-compile</phase>
<configuration>
<testExcludes>
<exclude>**/package-info.java</exclude>
</testExcludes>
</configuration>
<goals>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>

Question Regarding External Jars and MAVEN

I have two GWT projects Project A and Project B.The dependencies of these projects are taken care by MAVEN.Project B depends on Project A ,and this part is already taken care of.
Now i need to add an external Jar into Project A.I do not want to use Maven for this .I just want to add the external jar file into Project A and update my ProjectA.gwt.xml to inherit the jar.
So i included the jar file in Project A.But Project B was not recognizing the classes in the jar.So i went ahead and followed the following steps
1) Right Clicked on Project A and selected Build Path
2) Click on Configure Build Path
3) Order and Export the jar file
Then after doing so ,my Project B could compile the classes used from the JAR file.But at Runtime its crashing.Its not able to recognize the classes from the JAR file.
Can anyone provide me what to do on this?
Please provide me solution with/without using MAVEN.I would prefer without using MAVEN.
Thanks
I think you should keep all the dependency management in Maven.
The Eclipse Maven plugin manage the Build Path Configuration of your Eclipse project, it should be not modified manually.
You could use this configuration to add external librairies to the repository :
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-install-plugin</artifactId>
<version>2.3</version>
<executions>
<execution>
<id>deploy-on-local-repo1</id>
<phase>generate-sources</phase>
<goals>
<goal>install-file</goal>
</goals>
<inherited>false</inherited>
<configuration>
<file>src/your-librairie.jar</file>
<groupId>com.yourlibrairiegroupID</groupId>
<artifactId>librairie-name</artifactId>
<version>1.0</version>
<packaging>jar</packaging>
<generatePom>true</generatePom>
</configuration>
</execution>
</executions>
</plugin>
Hope it will fix your problem.

How do I get Eclipse to resolve classes generated with Maven 2?

I'm using Google Protocol Buffers to generate some Java classes for my project. Using Maven 2 and its "antrun" plugin, these classes are freshly generated before compile, output to target/generated-sources and put on the classpath during the build. So building the project from the POM is no problem.
However, Eclipse doesn't know how to resolve the generated class, because the folder it's in doesn't seem to be on the IDE's classpath during development. I'm using m2eclipse and have it manage dependencies for me, so I had expected Maven to take care of this.
How can I get IDE support (code completion etc.) for the generated code?
m2eclipse supports this. First, add the path to your build path:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.8</version>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources/java/</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
Second, add support for that to m2e:
<pluginManagement>
<plugins>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<versionRange>[1.0,)</versionRange>
<goals>
<goal>parse-version</goal>
<goal>add-source</goal>
<goal>maven-version</goal>
<goal>add-resource</goal>
<goal>add-test-resource</goal>
<goal>add-test-source</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute>
<runOnConfiguration>true</runOnConfiguration>
<runOnIncremental>true</runOnIncremental>
</execute>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
The second step might not be necessary, if your eclipse installation has installed the "org.eclipse.m2e.discovery.lifecyclemapping.buildhelper.xml" plugin. This plugin is available via Window -> Preferences -> Maven -> Discovery. Currently, that does not work here at Eclipse Kepler, therefore, I fetched the JAR (linked from the xml shown in the Catalog URL) and extracted the fragments from org.eclipse.m2e.discovery.lifecyclemapping.buildhelper.xml by hand.
m2eclipse doesn't support this. You must manually add the folder target/generated-sources as a source folder. When you tell m2eclipse to "Update Project Configuration", this will be overwritten and you have to restore it.
Also, make sure that Eclipse looks for changes in the workspace.
There might be some issues, though. Eventually, you'll run into errors that some class can't be compiled because some other class can't be resolved. Code completion will work, though. The root cause of this issue is that Eclipse gets confused when Maven changes class files in target.
To solve this, you must tell Eclipse to compile to a different place than Maven.
What you should see in your project explorer is a container named "Maven Dependencies" in place of the usual "Referenced libraries". This means m2eclipse is managing your build path.
In my case, to achieve this, I checked "Include Modules" and unchecked "Skip Maven compiler plugin when processing resources" on the "Maven" section of Project->Properties.
Personally I resolved this problem by setting up the generated classes as a seperate project and made it a dependency in my main (non-generated) project. I was using wsdl2java to generate webservice classes so the "source" in my sub-project was the wdsl and xsds. Worked well even when the wsdl was changing regularly.
I had this issue with code generated using Maven and wsdl2java and here's what I did in Eclipse Juno to resolve it. Assume my project is named project1:
Right-click project1 and select Properties
Choose Java Build Path from the left and select the Libraries tab
Click Add Class Folder
Select the bin directory and click OK (project1/target/generated-sources/bin)
Click OK and Refresh the project
As an added bonus you can also attach the source code:
Click the arrow next to the new class folder you just created
Click on Source attachment
Click the Edit button
Set the Path to /project1/target/generated-sources/axis2/src
Click OK
Right-click project and select Properties
Choose Java Build Pathfrom the left and select the Source tab
Click Add Folder
Select the bin directory and click OK
(project/target/generated-sources/xxxx) Click OK and Refresh the project
How can I get IDE support (code completion etc.) for the generated code?
Typically I would add the m2e lifecycle-mapping plugin to the pom.xml file as described in #koppor's answer. However adding per-eclipse code to my pom.xml files is not an option at work which is mostly an IntelliJ shop.
My solution first adds the build-helper-maven-plugin to the pom.xml which works fine from the command line but not in eclipse.
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources/</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
To fix eclipse I installed the Apt M2E Connector from the Eclipse Marketplace. I think things started working right after I restarted and then rebuilt all of my projects. I now see the following in my source dirs:
src/main/java
target/generated-sources
...
Feature!
Did you try to refresh the Eclipse project?
(source: oyvindhauge.com)
When an external tool generate new files or updates old ones, Eclipse will not be able to detect the change until the next request.
Another option would be to define a new Custom builder, specifying for that builder to "refresh resources upon completion":
alt text http://www.cs.lth.se/EDA180/2005/Verktyg/eclipse_refresh.gif
Worked for me (But you will to have to follow this every time so you can add this path in pom.xml)
Right click on your project > Build Path > Configure Build Path
In sources tag, click on [Add Folder] button
Check target/generated-sources/annotations
To generate Java source files from .proto files use Protocol Buffers Plugin which works out-of-the-box in eclipse Oxygen.
Basic usage (see here for detailed description):
make sure that native protoc compiler is installed on your system
update your pom.xml file:
make sure you use at least Java 6 (Java 7+ is recommended)
add plugin invocation
add the corresponding dependency for com.google.protobuf:protobuf-java
put your .proto files inside project's src/main/proto directory
update the project (via Maven -> Update project...)
Example pom.xml:
<project>
...
<build>
<plugins>
<!-- Require at least Java 6 -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
<!-- Generate .java files from .proto definitions -->
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.5.1</version>
<configuration>
<protocExecutable>/usr/local/bin/protoc</protocExecutable>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>3.5.1</version>
</dependency>
...
</dependencies>
...
</project>
Some additional notes:
if protoc executable is in the PATH the protocExecutable configuration entry can be omitted
test-only protobuf message definitions can be put into project's src/test/proto directory
I recommend installing Protocol Buffer Descriptor Editor (marketplace link)
Good luck!

GWT/Eclipse/Jetty issue: Jasper can't resolve tag libraries

I'm trying to get GWT Hosted mode working in Eclipse, à la this HOWTO. Servlets work fine, as does my GWT code, but all my JSPs fail because with errors such as the following:
[WARN] /view/lniExecutiveSummary.htm
org.apache.jasper.JasperException: /WEB-INF/jsp/lni/lniExecutiveSummary.jsp(1,1) The absolute uri: http://java.sun.com/jsp/jstl/fmt cannot be resolved in either web.xml or the jar files deployed with this application
at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:409)
[ trimmed ]
This webapp works fine when deployed under Tomcat 5x; I just can't seem to get it to resolve the taglibs when running in Eclipse.
I'm new to Eclipse, and getting it working with all the moving parts required for GWT+Maven has me pulling my hair out.
Update: I'm no longer using Eclipse; I've switched (back!) to Intellij IDEA. So I can't honestly evaluate the answers you kind folks have posted. Once some voting action happens, or someone else reports success with one of these methods, I'll accept the appropriate answer. Thanks.
I feel your pain. I've gone thru the same pain trying to get gwt, maven, and eclipse to work together.
I've been able to get it working with maven using the following pom.xml. This way you can use mvn gwt:run to run in hosted mode, but unfortunately, I could never get the mvn goal mvn gwt:eclipse for generating an eclipse launch run time config to work.
Here's the relevant snippets from my pom.xml. Note that I've found it easier to install gwt in separate location and point maven to use that instead of having mvn download gwt from repo. The "system" level scope in the mvn dependencies are what make this happen.
<properties>
<!-- convenience to define GWT version in one place -->
<gwt.version>1.7.1</gwt.version>
<google.webtoolkit.home>${env.GWT_HOME}</google.webtoolkit.home>
<!-- tell the compiler we can use 1.5 -->
<maven.compiler.source>1.6</maven.compiler.source>
<maven.compiler.target>1.6</maven.compiler.target>
</properties>
<dependencies>
<!-- GWT dependencies (from central repo) -->
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwt.version}</version>
<scope>system</scope>
<systemPath>${env.GWT_HOME}/gwt-servlet.jar</systemPath>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwt.version}</version>
<scope>system</scope>
<systemPath>${env.GWT_HOME}/gwt-user.jar</systemPath>
</dependency>
... other dependencies...
</dependencies>
<build>
<outputDirectory>war/WEB-INF/classes</outputDirectory>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>1.1</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>generateAsync</goal>
<goal>test</goal>
</goals>
</execution>
</executions>
<configuration>
<runTarget>com.gwt.example/Application.html</runTarget>
<extraJvmArgs>-Xmx512m</extraJvmArgs>
</configuration>
</plugin>
<!--
If you want to use the target/web.xml file mergewebxml produces,
tell the war plugin to use it.
Also, exclude what you want from the final artifact here.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<webXml>target/web.xml</webXml>
<warSourceExcludes>.gwt-tmp/**</warSourceExcludes>
</configuration>
</plugin>
-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.0.2</version>
<configuration>
<source>${maven.compiler.source}</source>
<target>${maven.compiler.target}</target>
<module>com.gwt.example</module>
</configuration>
</plugin>
</plugins>
...rest of pom.xml...
Another technique I've had success with is to use the eclipse google gwt plugin. Just use the wizard to create a new gwt project, make sure that you can run it from eclipse, then modify with your own code.
This webapp works fine when deployed under Tomcat 5x; I just can't seem to get it to resolve the taglibs when running in Eclipse. I'm new to Eclipse, and getting it working with all the moving parts required for GWT+Maven has me pulling my hair out.
You apparently have the JSTL JAR file(s) in Tomcat/lib instead of WEB-INF/lib. You can fix this in at least three ways:
Move/copy the JSTL JAR file(s) into WEB-INF/lib.
Move/copy the JSTL JAR file(s) into Tomcat/lib of your development machine.
Associate the right Tomcat server containing the JSTL JAR file(s) with web project in Eclipse. If not done yet, add the Tomcat server in Servers view. Then in project properties go to Java Build Path > Libraries > Add Library > Server Runtime > select the server in question.
Add the Jar files in eclipse project classpath. if you already had this file tomcat lib. This option will works for you. Second option is add jar in Web-Inf lib folder if you have eclipse web project.
Did you try to mark the "jsf-api.jar" as "exported" in your Java project ?
(as mentioned in this thread)
1.) Go into the java-project properties and mark the "jsf-api.jar" as exported.
(project>properties>java build path>order and exports)
2.) Go into the advanced global tomcat preferences and add your project to
the tomcat classpath (windows>preferences>tomcat>advanced>add projects to
tomcat classpath)
Then, try again to run your webapp under eclipse.
Here is an article describing the same procedure/setup, not for JSF but Hudson (same problem though)
You can clearly see the two steps I mentioned above:
(source: hudson-ci.org)
(source: hudson-ci.org)