Apex Based Sharing in Salesforce

Test_Share Trigger.java

trigger Test_Share on Test__c (after insert) {
    if(trigger.isInsert){

    /**
     * Test_Share is the "Share" table that was created when the Organization Wide Default
    *  sharing setting was set to "Private". Allocate storage for a list of Test_Share
    * records.
    **/
    List<Test_Share> jobShares = new List<Test_Share>();

    /** For each of the Test records being inserted, do the following: **/
    for(Test__c t : trigger.new){
        /** Create a new Test_Share record to be inserted in to the Test_Share table. **/
        Test_Share studentRecord = new Test_Share();
        /** Populate the Test_Share record with the ID of the record to be shared. **/
        studentRecord.ParentId = t.Id;
        /** Then, set the ID of user or group being granted access. In this case,
         * we're setting the Id of the student__c that was specified by the Test
         * Result in the student__c lookup field on the Test record.
         **/
        studentRecord.UserOrGroupId = t.student__c;
        /** Specify that the Student should have edit access for this particular Test record. **/
        studentRecord.AccessLevel = 'edit';
        /** Specify that the reason the Student can edit the record is because its his test result
         * (Student_Access__c is the Apex Sharing Reason that we defined earlier.)
         **/
        studentRecord.RowCause = Schema.Test_Share.RowCause.Student_Access__c;
        /** Add the new Share record to the list of new Share records. **/
        jobShares.add(studentRecord);
    }
    /** Insert all of the newly created Share records and capture save result **/
    Database.SaveResult[] jobShareInsertResult = Database.insert(jobShares,false);
    }
}