Tuesday, November 11, 2014

How to execute maven goal on parent module but not on childer

I am working on multi module maven project and If I define any plugin in the parent pom.xml file, It get executed for all the child build as well.

In simple language, I wanted to use one plugin in parent pom.xml file which read properties file from the base directory but whenever I executes it, all the sub pom.xml tries to read the properties file from their base directory and its ends up in maven failed.

To resolve the above issue, We just need to add "inherit' attributes in the plugin.

Example :

<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>properties-maven-plugin</artifactId>
<version>1.0-alpha-2</version>
<inherited>false</inherited>
<executions>
<execution>
<phase>initialize</phase>
<goals>
<goal>read-project-properties</goal>
</goals>
<configuration>
<files>
<file>${basedir}/rpm.properties</file>
</files>
</configuration>
</execution>
</executions>
</plugin>

Now the plugin will get executed from the parent pom.xml file.

Thank you :)

Thursday, October 30, 2014

How to Map a list of strings with JPA/Hibernate annotations ?

Yesterday while working on my project, I got one requirement where I need to store list of Array into the database, I checked on Google, went through various site but didn't get much information. Everyone talks about creating new entity and do onetomany relationship BUT I wanted to create a collection of basic types.

Finally I come across @ElementCollection annotation provided by JPA 2.0 which resolves my problem.

Problem :
Input JSON which we need to store in DB:

{
"schemas": ["urn:scim:schemas:core:1.0", "urn:scim:schemas:extension:enterprise:1.0"]
}
           Where schemas is Array of String.
Solution :


Just add following annotation in your POJO i,e
@ElementCollection
@CollectionTable(name = "SCIM_SCHEMAS", joinColumns = @JoinColumn(name = "SCHEMA_ID"))
@Column(name = "SCIM_SCHEMA")
private List<String> schemas;

It will create the table named "SCIM_SCHEMAS" having columns 'SCHEMA_ID' and 'SCIM_SCHEMA'


For details check section 2.2.5.3.3. Collection of basic types or embeddable objects or feel free to comment :)



Thursday, October 16, 2014

How to create Java Classes using xjc from XML file

This tutorial will demonstrate how can you generate Java Objects from XML documents using xjc tool. The tool “xjc” is used to generate the annotated Java classes from the XSD schema

Suppose I am using below XML file to generate Java Objects i,e
<?xml version="1.0" encoding="UTF-8"?>
<adaptorapp id="application">
<instance id="instance1">
<connectiondetails>
<accesskey>abcde</accesskey>
<secretkey>fghij</secretkey>
</connectiondetails>
</instance>
<instance id="instance2">
<connectiondetails>
<accesskey>klmnop</accesskey>
<secretkey>qrstuvwxyz</secretkey>
</connectiondetails>
</instance>
</adaptorapp>
Now  to generate Java Objects we need to create one xsd file(say "connection.xsd") :
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="adaptorapp" type="AdaptopApp" />
<xs:complexType name="AdaptopApp">
<xs:sequence>
<xs:element name="instance" type="Instance" maxOccurs="unbounded" />
</xs:sequence>
<xs:attribute name="id" type="xs:string" use="required" />
</xs:complexType>
<xs:complexType name="Instance">
<xs:sequence>
<xs:element name="connectiondetail" type="ConnectionDetail" />
</xs:sequence>
<xs:attribute name="id" type="xs:string" use="required" />
</xs:complexType>
<xs:complexType name="ConnectionDetail">
<xs:sequence>
<xs:element name="accesskey" type="xs:string" />
<xs:element name="secretkey" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:schema>
I have written XSD Schema based on my XML file, You can write something similar according to your requirement.

Lets use the 'xjc" tool to generate corresponding Java classes
                xjc.exe connection.xsd
By default, It will generates the Java classes in a directory named "generated".


Please let me know your feedback/queries as comments.

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