Java bug | Techartifact

August 16, 2012

Attach sources & javadocs in maven project

Maven allows to publish project source code and javadoc with complied artifact. Maven source plugin and javadoc can do it easily for you.

Here is pom configuration for it.

Attaching source

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-source-plugin</artifactId>
  <executions>
    <execution>
      <id>attach-sources</id>
      <goals>
        <goal>jar</goal>
      </goals>
    </execution>
  </executions>
</plugin>

Maven source plugin also allows to package test source codes

Attaching test source code

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-source-plugin</artifactId>
  <executions>
    <execution>
      <id>attach-test-sources</id>
      <goals>
        <goal>test-jar</goal>
      </goals>
    </execution>
  </executions>
</plugin>

Attaching javadocs

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-javadoc-plugin</artifactId>
  <executions>
    <execution>
      <id>attach-javadocs</id>
      <goals>
        <goal>jar</goal>
      </goals>
    </execution>
  </executions>
</plugin>

you achieve it by issuing any of following maven commands

mvn package

mvn install

Please refer to maven plugin website for more information

source-plugin http://maven.apache.org/plugins/maven-source-plugin/

javadoc-plugin http://maven.apache.org/plugins/maven-javadoc-plugin/

August 14, 2012August 16, 2012

Ehcache SimplePageCachingFilter

Add caching layer on your web application, with out modifying the code.

SimplePageCachingFilter

Ehcache has an out-of-box of solution for this ‘SimplePageCachingFilter’.
SimplePageCachingFilter is caching filter can be use full for html or any other response type
e.g JSON or xml. It uses singleton Ehcache manager to store contents. Cache keys are calculated
using the URI and query string. /exampleData?user=admin&role=admin.

There is another variant of ‘SimplePageCachingFilter’ based on headers ‘SimpleCachingHeadersPageCachingFilter’.
This filter take account headers for cache key. It take three account of headers

ETag
Last-Modified
Expires

Configuration

cacheName
Cache used by filter for storing content

blockingTimeoutMillis
the time, in milliseconds, to wait for the filter chain to return with a response on a cache miss. This is useful to fail fast in the event of an infrastructure failure.

varyHeader
set to true to set Vary:Accept-Encoding in the response when doing Gzip. This header is needed to support HTTP proxies however it is off by default.

Web.xml

<filter>
<filter-name>SimplePageCachingFilter</filter-name>
 <filter-class>net.sf.ehcache.constructs.web.filter.
SimplePageFragmentCachingFilter
 </filter-class>
 <init-param>
  <param-name>cacheName</param-name>
  <param-value>simplePageCache</param-value>
 </init-param>
</filter>
<filter-mapping>
<filter-name>SimplePageCachingFilter</filter-name>
 <url-pattern>/*</url-pattern>
</filter-mapping>

Ehcache configuration

<Ehcachexmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="../../main/config/ehcache.xsd">
<diskStorepath="java.io.tmpdir"/>
 <defaultCache
   maxEntriesLocalHeap="10"
   eternal="false"
   timeToIdleSeconds="5"
   timeToLiveSeconds="10"
   overflowToDisk="true"
   />
  <!-- Page and Page Fragment Caches -->
<cachename="simplePageCache"
  maxEntriesLocalHeap="10"
  eternal="false"
  timeToIdleSeconds="10000"
  timeToLiveSeconds="10000"
  overflowToDisk="true">
</cache>
</ehcache>

Pros

No code is required.
It allows the content compressing.
This can be integrated with Spring WebFramework too.

Cons

It do caching based on complete response.
It doesn’t take custom headers in account.

June 25, 2012June 30, 2012

RESTFul Service example using Apache CXF and Spring

In recent times there is lot of growth in RESTFul services. I thought it would be nice to talk about it.

This example is using Apache CXF and Spring. There are some other frameworks e.g Jersey (Reference Sun implementation), RestEasy, the JBoss choice and Apache CXF.

Here is bacic web configuration adding Spring context and CXF tranport servlet.

  <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/services.xml</param-value>
    </context-param>


    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>CXFServlet</servlet-name>
        <servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>CXFServlet</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>

There is Cities service using Spring annotations, this has been configured using Spring annotation
Second annottatiions is of CXF to define the mount point REST service

@Service("timeService")
@Path("cities")
public class CitiesListingService {

    @GET
    @Produces({"application/json", "application/xml"})
    public RestFulCities getCities() {
        List<City> cities = new LinkedList<City>();
        cities.add(new City("New Delhi", "011", "19M"));
        cities.add(new City("Mumbai", "022", "21M"));
        cities.add(new City("Chennai", "044", "10M"));
        RestFulCities restFulCities = new RestFulCities();
        restFulCities.setRestFulCityList(getCities(cities));
        return restFulCities;
    }

Here is Spring configuration for connection cxf and spring beans together.

<context:component-scan base-package="com.techartifact.example.spring"/>

    <import resource="classpath:META-INF/cxf/cxf.xml"/>
    <import resource="classpath:META-INF/cxf/cxf-extension-jaxrs-binding.xml"/>
    <import resource="classpath:META-INF/cxf/cxf-servlet.xml"/>

    <jaxrs:server id="restContainer" address="/">
        <jaxrs:serviceBeans>
            <ref bean="timeService"/>
        </jaxrs:serviceBeans>
        <jaxrs:extensionMappings>
            <entry key="json" value="application/json"/>
            <entry key="xml" value="application/xml"/>
        </jaxrs:extensionMappings>
        <jaxrs:providers>
            <ref bean="jaxbXmlProvider"/>
        </jaxrs:providers>
    </jaxrs:server>

    <!-- Webservice message handlers -->
    <bean id="jaxbXmlProvider" class="org.apache.cxf.jaxrs.provider.JAXBElementProvider">
        <property name="jaxbElementClassNames" ref="elements"/>
    </bean>

    <util:list id="elements">
        <value>com.techartifact.example.spring.model.RestFulCity</value>
        <value>com.techartifact.example.spring.model.RestFulCities</value>
    </util:list>

Yes that’s it. Now build the code and run it.