log4j filter some text and don't log it

Use org.apache.log4j.varia.StringMatchFilter to filter the text not to display.  Here is the example for log4j.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
  <appender name="console" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} [%t] %-5p - %m%n" />
    </layout>

    <filter class="org.apache.log4j.varia.StringMatchFilter">
      <param name="StringToMatch" value="the-text-not-to-log" />
      <param name="AcceptOnMatch" value="false" />
    </filter>

    <!-- <filter class="org.apache.log4j.varia.DenyAllFilter" /> -->
  </appender>

  <root>
    <priority value="info" />
    <appender-ref ref="console" />
  </root>
</log4j:configuration>

Then run the following to test:

        LOG.info("This is an info and shouldn't be logged with the-text-not-to-log and blah blah");
        LOG.info("This is logged");
        LOG.debug("This is a debug and not logged");
        LOG.error("This is an error and logged");

If you only want to log some text, then change the value for AcceptOnMatch to true and add DenyAllFilter.

mac: no acceptable C compiler found in $PATH

If you get the following error on mac:

configure: error: no acceptable C compiler found in $PATH

Here is the step to fix it:

1. download Xcode from https://developer.apple.com/downloads/index.action
2. install Xcode
3. Open Xcode, go to Preferences --> Downloads --> install "Command Line Tools"
4. relaunch terminal

Enable Spring Jdbc Transaction with Annotation

Spring 3.1 introduced a new annotation @EnableTransactionManagement.  With it, all xml configuration can be got rid of now.  Here is the example on how to use it:

@Configuration
@EnableTransactionManagement
public class JdbcConfig {

    @Bean
    public DataSource dataSource() {
    //config datasource      
    }

    @Bean
    public PlatformTransactionManager txManager() {
        return new DataSourceTransactionManager(dataSource());
    }

    @Bean
    public MyDao myDao() {
        MyDaoJdbc dao = new MyDaoJdbc();
        dao.setDataSource(dataSource());
        return dao;
    }
}

Next you need to annote your dao with @Transactional.  The source code can be found at github:

https://github.com/zhentao/spring-jdbc-transaction-example

cobertura-maven-plugin

Recently I created a parent pom for my team to use.  All my team's projects need to inherit this parent pom.  This parent pom is rather simple:

  <properties>
    <default.encoding>UTF-8</default.encoding>
    <default.jdk>1.6</default.jdk>
    <line.coverage.target>90</line.coverage.target>
    <branch.coverage.target>90</branch.coverage.target>
  </properties>

  <build>
    <defaultGoal>install</defaultGoal>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>2.3.2</version>
          <configuration>
            <source>${default.jdk}</source>
            <target>${default.jdk}</target>
            <encoding>${default.encoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-source-plugin</artifactId>
          <version>2.1.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>2.5</version>
          <configuration>
            <encoding>${default.encoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-javadoc-plugin</artifactId>
          <version>2.8</version>
          <configuration>
            <encoding>${default.encoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-release-plugin</artifactId>
          <version>2.2.2</version>
        </plugin>

        <!-- Sonar uses these versions, below -->
        <plugin>
          <artifactId>maven-pmd-plugin</artifactId>
          <version>2.7.1</version>
          <configuration>
            <targetJdk>${default.jdk}</targetJdk>
            <encoding>${default.encoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <artifactId>maven-checkstyle-plugin</artifactId>
          <version>2.9.1</version>
          <configuration>
            <encoding>${default.encoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.codehaus.mojo</groupId>
          <artifactId>cobertura-maven-plugin</artifactId>
          <version>2.5.1</version>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.12</version>
        </plugin>
      </plugins>
    </pluginManagement>

    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>cobertura-maven-plugin</artifactId>
        <configuration>
          <check>
            <!-- Per-class thresholds -->
            <branchRate>${branch.coverage.target}</branchRate>
            <lineRate>${line.coverage.target}</lineRate>
            <!-- Project-wide thresholds -->
            <totalLineRate>${line.coverage.target}</totalLineRate>
            <totalBranchRate>${branch.coverage.target}</totalBranchRate>
          </check>
          <formats>
            <format>html</format>
          </formats>
        </configuration>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>clean</goal>
              <goal>cobertura</goal>
              <goal>check</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
      </plugin>
      <plugin>
        <!-- Ensure that source code is packaged and deployed for inclusion into IDEs -->
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-source-plugin</artifactId>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>jar</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

    </plugins>
  </build>

We are targeting a pretty high unit test coverage, 90% for both line and branch coverage.  However, some classes don't need unit test or don't need high coverage.  Then each individual project can include the following to its project pom:

    <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>cobertura-maven-plugin</artifactId>
        <configuration>
          <instrumentation>
            <ignores>
              <ignore>org.slf4j.*</ignore>
            </ignores>
            <excludes>
              <exclude>com/zhentao/Some.class</exclude>
              <exclude>com/zhentao/other.class</exclude>
            </excludes>
          </instrumentation>
        </configuration>
      </plugin>
    </plugins>
  </build>

 <ignore>org.slf4j.*</ignore> ignores all log statement in the code since we don't need to test logs.
<exclude>com/zhentao/Some.class</exclude> excludes Some.class from the cobertura report.

However, this flexibility can be abused by some developers.  I got an build failed notification today:

11:52:52  Archiving artifacts
11:52:52  [htmlpublisher] Archiving HTML reports...
11:52:52  [htmlpublisher] Archiving at PROJECT level /target/site/cobertura to /htmlreports/Cobertura_Report
11:52:52  ERROR: Specified HTML directory '/target/site/cobertura' does not exist.
11:52:52  Build step 'Publish HTML reports' changed build result to FAILURE

 One developer excluded all classes from testing.  What a developer!

Yahoo hadoop tutorials

This is the link from yahoo for hadoop tutorials:

http://developer.yahoo.com/hadoop/tutorial/index.html