StringTemplate to generate Cobol layout - cobol

Question

I am tasked with writing some Java to read data from a DB2 table and write into a file in a fixed with format that can be input to a Cobol program.
The Cobol layout looks like so
01 PERSON
10 FIRST-NAME PIC X(10) (i.e 10 bytes fixed width)
10 LAST-NAME PIC X(20) (i.e 20 bytes fixed width)
10 MIDDLE-INITIAL PIC X(1)
In Java the fields are available to me as Strings. Using the docs I came up with something like this
class Person {
private String firstName;
private String lastName;
private String middleInitial;
Person(String inFirstName, String inLastName, String inMiddleInitial){
this.firstName = inFirstName;
this.lastName = inLastName;
this.middleInitial = inMiddleInitial;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public String getMiddleInitial() {
return middleInitial;
}
}
and then in main, I had these lines of code
st = new ST("$p.firstName$ $p.lastName$ $p.middleInitial$", '$', '$');
st.add("p", new Person("Ethelred", "TheUnready", "X"));
System.out.println(st.render());
Executing produces this result
Ethelred TheUnready X
What should I do to ensure the output looks like so
Ethelred TheUnready X
while a name like John Q Smith would like so
John Smith Q
Thanks!

Answer 1

You could do something like
spaces = " "
outLine = (firstName + spaces).substring(0,10)
+ (lastName + spaces).substring(0,20)
+ middleInitial;
There are a number of packages for writing Fixed width files from java (have a search of Sourceforge).
There are even a few packages that can use a Cobol Copybook to read/write the file:
JRecord
cobol2j
legstar
These packages are an overkill in this case but are useful if the copybook is more complicated.
disclaimer I wrote JRecord.