"The Apache Ignite Book" distribution channels

From this year we have added a few more channels for distributing our book "The Apache Ignite book", which is considered as one of...


Code review with Sonar

Last week Sonar announced their new version 2.8 with a few new features and bug fixes. The main new feature is the support of custom code review. Crucible and Review board are another alternative code review system. Sonar come across with code coverage and review in one system, which is easy to maintain with small effort.
As usual sonar administrator must create users to assign tasks and collaborations. Sonar provide LDAP plugin which enables the delegation of Sonar authentication to an external system. Currently LDAP plugin supports LDAP and Active directory. In our corporation we are using active directory and first of all i tried to configure the LADP plugin. LDAP plugin wiki fully describes the installation of the plugin with LDAP system but poorly with AD. With some effort with my boss we were able to configure the plugin with our AD system. Follows i am sharing the configuration:
# Sonar LDAP Plugin

# IMPORTANT : before activation, make sure that one Sonar administrator is defined in the external system
# Activates the plugin. Leave blank or comment out to use default sonar authentication.
sonar.authenticator.class: org.sonar.plugins.ldap.LdapAuthenticator

# Ignore failure at startup if the connection to external system is refused.
# Users can browse sonar but not log in as long as the connection fails.
# When set to true, Sonar will not start if connection to external system fails.
# Default is false.
#sonar.authenticator.ignoreStartupFailure: true

# Automatically create users (available since Sonar 2.0).
# When set to true, user will be created after successful authentication, if doesn't exists.
# The default group affected to new users can be defined online, in Sonar general settings. The default value is "sonar-users".
# Default is false.
#sonar.authenticator.createUsers: true

# (omit if you use autodiscovery) URL of the LDAP server.
# If you are using ldaps, then you should install server certificate into java truststore.
# eg. ldap://localhost:10389
ldap.url: ldap://

# (optional) Distinguished Name (DN) of the root node in LDAP from which to search for users,
# eg. “ou=users,o=mycompany”
ldap.baseDn: dc=mycompany,dc=com

# (optional) Bind DN is the username of an LDAP user to connect (or bind) with.
# This is a Distinguished Name of a user who has administrative rights,
# eg. “cn=sonar,ou=users,o=mycompany”. Leave blank for anonymous access to the LDAP directory.
ldap.bindDn: ADADMIN

# (optional) Bind Password is the password of the user to connect with.
# Leave blank for anonymous access to the LDAP directory.
ldap.bindPassword: ADADMIN_PASSWORD

# Login Attribute is the attribute in LDAP holding the user’s login.
# Default is ‘uid’. Set ’sAMAccountName’ for Microsoft Active Directory
ldap.loginAttribute: sAMAccountName

# Object class of LDAP users.
# Default is 'inetOrgPerson'. Set ‘user’ for Microsoft Active Directory.
ldap.userObjectClass: user

# (advanced option) See
# Default is 'simple'. Possible values: 'simple', 'CRAM-MD5', 'DIGEST-MD5', 'GSSAPI'.
ldap.authentication: simple

# (advanced option)
# See
# eg.

# (advanced option) Context factory class.
# Default is 'com.sun.jndi.ldap.LdapCtxFactory'.
#ldap.contextFactoryClass: com.sun.jndi.ldap.LdapCtxFactory
Configuration may vary on your AD system, strongly guess system administrator may help in this issue.
For now in the time of the authentication, Sonar will ignore the password from it's own system and delegate the username and password to the active directory for authentication. Also sonar administrator must configure the role for each user independently.
After installing plugin we are ready to go for code review. On the violations tab we should see the review link as follows:
Now we can add comments on violations, by default task will assign to the author of the comment:
After creating the task we also can reassign the task to another user as follows:
All the reviews you can get from the dash board
For more screen shots you should visit this link (sonar-2-8-in-screenshots).
One shortage of the sonar code review is the lack of notification, when any comment or task assign to the users. I believe that, in future release sonar will add this notification functionality in code review.


Apache maven incremental build

Apache maven is one of the popular tool for building and managing java projects. Based on the concept of a project object model (POM), Maven can manage a project's build, reporting and documentation from a central piece of information.
However when you have projects with multiple modules, it follows some issue when you compiling your project. One of them is incremental building, which means when you updates your project from the version control, you have to build the entire system by command mvn clean install. Consider the following maven project structure:
|_ _ test-api
|_ _ test-api-impl
|_ _ test-donothing
where module test-api-impl dependent on module test-api. Whenever we will make some change on module test-api, we have to recompile and build the module test-api-impl.
If we will enter the command mvn install module test-api-impl will not get the updated version from the module test-api. You have to run command mvn clean install which will rebuild the entire project. Sometime it's time consuming and just unnecessary. You can download the project from here and check your self.
Apache maven currently doesn't support for the incremental build even on version 3.0.3.
But there is a plugin called Maven-Incremental build plugin, which can build project incrementally.
Just add the following plugin in the root pom file and you are ready for go
Now you can run mvn install without goal clean and the project will detects the updated code and recompile modules if need.
UPD:- Note that, following page contains incorrect groupId on example "" which will not uploaded on central maven repository.
1) Apache Maven Incremental Build support for WSO2 Carbon
2) Apache maven incremental plugin mojo