envimate-java-standards

Contains the java quality standards for envimate projects

Usage

Replace the top section of your pom with the following:

<!--
  ~ Copyright (c) 2018 envimate GmbH - https://envimate.com/.
  ~
  ~ Licensed to the Apache Software Foundation (ASF) under one
  ~ or more contributor license agreements.  See the NOTICE file
  ~ distributed with this work for additional information
  ~ regarding copyright ownership.  The ASF licenses this file
  ~ to you under the Apache License, Version 2.0 (the
  ~ "License"); you may not use this file except in compliance
  ~ with the License.  You may obtain a copy of the License at
  ~
  ~   http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing,
  ~ software distributed under the License is distributed on an
  ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  ~ KIND, either express or implied.  See the License for the
  ~ specific language governing permissions and limitations
  ~ under the License.
  -->

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                      http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.envimate</groupId>
        <artifactId>envimate-opensource-parent</artifactId>
        <version>1.0.11</version>
    </parent>

Also make sure that the README.md of the project clearly recommends the usage of the pgpverify-maven-plugin by providing the link https://youtu.be/ES9hWkn_WBA?t=27m29s . It can be found under https://www.simplify4u.org/pgpverify-maven-plugin/ usage instructions.

Checkstyle

Checkstyle is enabled after using this pom as parent in a maven project and executed before tests are run.

Registering Checkstyle suppressions

Add the following to your pom:

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                      http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
        ...
    <properties>
        ...
        <checkstyle.suppressions.location>
            ${project.basedir}/src/test/checkstyle/checkstyle-suppressions.xml
        </checkstyle.suppressions.location>
    </properties>
    ...
</project>

And create the suppression configuration file under /src/test/checkstyle/checkstyle-suppressions.xml with the contents of your choosing based on the following example:

<?xml version="1.0" encoding="UTF-8"?>
<!--
  ~ Copyright (c) 2018 envimate GmbH - https://envimate.com/.
  ~
  ~ Licensed to the Apache Software Foundation (ASF) under one
  ~ or more contributor license agreements.  See the NOTICE file
  ~ distributed with this work for additional information
  ~ regarding copyright ownership.  The ASF licenses this file
  ~ to you under the Apache License, Version 2.0 (the
  ~ "License"); you may not use this file except in compliance
  ~ with the License.  You may obtain a copy of the License at
  ~
  ~   http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing,
  ~ software distributed under the License is distributed on an
  ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  ~ KIND, either express or implied.  See the License for the
  ~ specific language governing permissions and limitations
  ~ under the License.
  -->

<!DOCTYPE suppressions PUBLIC
        "-//Puppy Crawl//DTD Suppressions 1.1//EN"
        "http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
<suppressions>
    <suppress checks="VisibilityModifier" files=".*AggregatedValidationException.java" />
    <suppress checks="IllegalCatchCheck" files="NamedMethodSerializationCPMethod.java" />
    <suppress checks="IllegalCatchCheck" files="Deserializer.java" />
</suppressions>

The checkstyle step can be skipped for a run with -Dcheckstyle.skip

Intellij integration

Install the CheckStyle-IDEA plugin. Afterwards, open Settings -> Other Settings -> Checkstyle and add a new Checkstyle configuration file, name it EnvimateOpenSource and use https://raw.githubusercontent.com/envimate/envimate-opensource-parent/master/checkstyle/checkstyle.xml as a URL location.

Spotbugs

Spotbugs is enabled after using this pom as parent in a maven project and executed before tests are run.

Registering Spotbugs exclusions

Add the following to your pom:

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                      http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
        ...
    <properties>
        ...
        <spotbugs.excludeFilterFile>
            ${project.basedir}/src/test/spotbugs/spotbugs-exclude.xml
        </spotbugs.excludeFilterFile>
    </properties>
    ...
</project>

And create the suppression configuration file under /src/test/spotbugs/spotbugs-exclude.xml with the contents of your choice based on the following example:

<?xml version="1.0" encoding="UTF-8"?>
<!--
  ~ Copyright (c) 2018 envimate GmbH - https://envimate.com/.
  ~
  ~ Licensed to the Apache Software Foundation (ASF) under one
  ~ or more contributor license agreements.  See the NOTICE file
  ~ distributed with this work for additional information
  ~ regarding copyright ownership.  The ASF licenses this file
  ~ to you under the Apache License, Version 2.0 (the
  ~ "License"); you may not use this file except in compliance
  ~ with the License.  You may obtain a copy of the License at
  ~
  ~   http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing,
  ~ software distributed under the License is distributed on an
  ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  ~ KIND, either express or implied.  See the License for the
  ~ specific language governing permissions and limitations
  ~ under the License.
  -->

<FindBugsFilter
		xmlns="https://github.com/spotbugs/filter/3.0.0"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="https://github.com/spotbugs/filter/3.0.0 https://raw.githubusercontent.com/spotbugs/spotbugs/3.1.0/spotbugs/etc/findbugsfilter.xsd">
    <Match>
         <Class name="com.envimate.someClass"/>
         <Method name="aSpecificMethod"/>
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE"/>
    </Match>
    
    <Match>
         <Class name="com.envimate.differentClass"/>
         <Bug category="PERFORMANCE"/>
    </Match>

</FindBugsFilter>

More information about exclusions can be found on the spotbugs website: https://spotbugs.readthedocs.io/en/stable/filter.html#examples

Intellij integration

Install the Findbugs-IDEA plugin.

Compiler

The compiler is configured for all child projects and should not be modified in any of the child projects of this pom. Following this recommendation provides child projects with the following benefits:

• Encoding and Java version of the sources and compiled classes are managed
• A configuration bug fix, that will prevent the maven-compiler-plugin from swallowing compilation errors and hence failing with 'unknown compilation error'
• Building the child project in Intellij will be possible with warnings
• Building the child project using maven will be possible with warnings, if built with -DskipTests=true
• Testing the child project using maven will be possible with warnings, if built with -Dmaven.compiler.failOnWarning=false
• Building/Testing the child project will fail, if the source code is causing compiler warnings
• Releasing the child project will fail, if the source code is causing compiler warnings

Skipping tests

Just run the maven command with -DskipTests=true.

Long running tests, that should be executed before every release, but not on every verify

Surefire will set a SystemProperty testMode to either NORMAL or RELEASE depending on the active profile.

In the test, an if statement can be used:

final Boolean runThisTest = Optional.ofNullable(System.getProperty("testMode")).map(s -> s.equals("RELEASE")).orElse(false);
if (runThisTest) {
    //test you long running stuff
} else {
    System.out.println("Skipping this test, since system property testMode is not set to RELEASE");
}

Releasing a version to maven central

The problem with releasing to maven central using a CI/CD pipeline is complicated, since both, the nexus staging account and the gpg key must be kept private. If a very bad person gains access to one or both of these credentials users of our open source products are in grave danger (https://youtu.be/ES9hWkn_WBA?t=27m29s). A bitbucket pipeline can output secure environmental variables with some neat tricks. Since we would need to store both valuable credentials as such, that operation can only be done manually outside the bitbucket cloud environment:

• Ensure the gpg private key with the id 0xACB977BA5C6D5C6E installed in the gpg key store.
• Ensure the maven settings.xml file contains the following section:

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		  xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
	...
	<servers>
		<server>
			<id>envimate.opensource.sonatype.staging</id>
			<username>the username of the sonatype nexus staging account</username>
			<password>{the encrypted password of the Sonatype nexus staging account created using mvn --encrypt-password}</password>
		</server>
	</servers>
	...
</settings>

• ensure the project version has been set to the appropriate value
• run the following command to test the project:

mvn clean verify

• run the following command to release the project in case the tests passed:

mvn -DdeployToMavenCentral -DskipTests=true clean deploy

Excluding modules from being released to maven central

Sometimes a project needs a [test]module, that is not supposed to be released as an artifact to maven central. This is a tough nut, since the nexus staging plugin will only deploy to staging, if the last module of a multi modules build, is actually one that is supposed to be released. Especially test modules tend to be the last ones built and are not to be deployed, so disabling the staging plugin in these modules will essentially end up in the whole project not being released to staging. In these cases 2 profiles will do the trick. One that is called development, which includes ALL the modules and is activated on the missing property named deployToMavenCentral. The other profile is called deployToMavenCentral, contains only the modules that are intended to be released to maven central and is activated on the presence of the property named deployToMavenCentral. Example:

<profiles>
    <profile>
        <id>development</id>
        <activation>
            <activeByDefault>false</activeByDefault>
            <property>
                <name>!deployToMavenCentral</name>
            </property>
        </activation>
        <modules>
            <module>core</module>
            <module>integrations</module>
            <module>tests</module>
        </modules>
    </profile>
    <profile>
        <id>deployToMavenCentral</id>
        <activation>
            <activeByDefault>false</activeByDefault>
            <property>
                <name>deployToMavenCentral</name>
            </property>
        </activation>
        <modules>
            <module>core</module>
            <module>integrations</module>
        </modules>
    </profile>
</profiles>