Jira custom script validator: check if input textbox exists

Question

I am totally new to Jira. In fact I don't even know where to start. I went to the jira atlassian website but got nothing solid enough to help me. I would like to validate if the information entered into a textbox already exists. I clicked around jira and ended up on the screen below:

Now I would like to find out the following:

1. Which programming language should be used for validation ? Is it Java
2. If the name of the custom field(of type Textbox) is XYZ and I wanna if check if value entered into XYZ already exist, how do I go about doing that ? Can I just write conditional statements in Java ?

I wrote some stuff and nothing worked.

Answer 1

That's a screenshot from the Script Runner add-on.

There are some documentation and examples for custom validators here.

You can also find an example here that shows how to query the JIRA (or an external) database from a groovy script. Ie.:

import com.atlassian.jira.component.ComponentAccessor
import groovy.sql.Sql
import org.ofbiz.core.entity.ConnectionFactory
import org.ofbiz.core.entity.DelegatorInterface

import java.sql.Connection

def delegator = (DelegatorInterface) ComponentAccessor.getComponent(DelegatorInterface)
String helperName = delegator.getGroupHelperName("default");

def sqlStmt = """
    SELECT     project.pname, COUNT(*) AS kount
    FROM       project
               INNER JOIN jiraissue ON project.ID = jiraissue.PROJECT
    GROUP BY project.pname
    ORDER BY kount DESC
"""

Connection conn = ConnectionFactory.getConnection(helperName);
Sql sql = new Sql(conn)

try {
    StringBuffer sb = new StringBuffer()
    sql.eachRow(sqlStmt) {
        sb << "${it.pname}\t${it.kount}\n"
    }
    log.debug sb.toString()
}
finally {
    sql.close()
}

For anything that gets a bit complex it's easier to implement your script in a groovy file and make it available to Script Runner via the file system. That also allows you use a vcs like git to easily push/pull your changes. More info about how to go about that, is here.