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Do i have to create new exception for my interface

 
Greenhorn
Posts: 3
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Hi all,
in my interface :
Your data access class must be called "Data.java", must be in a package called "suncertify.db", and must implement the following interface:
package suncertify.db;
public interface DBMain {
// Reads a record from the file. Returns an array where each
// element is a record value.
public String [] read(int recNo) throws RecordNotFoundException;
// Modifies the fields of a record. The new value for field n
// appears in data[n].
public void update(int recNo, String [] data)
throws RecordNotFoundException;
// Deletes a record, making the record number and associated disk
// storage available for reuse.
public void delete(int recNo) throws RecordNotFoundException;
// Returns an array of record numbers that match the specified
// criteria. Field n in the database file is described by
// criteria[n]. A null value in criteria[n] matches any field
// value. A non-null value in criteria[n] matches any field
// value that begins with criteria[n]. (For example, "Fred"
// matches "Fred" or "Freddy".)
public int [] find(String [] criteria)
throws RecordNotFoundException;
// Creates a new record in the database (possibly reusing a
// deleted entry). Inserts the given data, and returns the record
// number of the new record.
public int create(String [] data) throws DuplicateKeyException;
// Locks a record so that it can only be updated or deleted by this client.
// If the specified record is already locked, the current thread gives up
// the CPU and consumes no CPU cycles until the record is unlocked.
public void lock(int recNo) throws RecordNotFoundException;
// Releases the lock on a record.
public void unlock(int recNo) throws RecordNotFoundException;
// Determines if a record is currenly locked. Returns true if the
// record is locked, false otherwise.
public boolean isLocked(int recNo)
throws RecordNotFoundException;
}
1. do i have to create new recordnotfoundexception.
2. if yes for que 1 . where ( is my taught right ) to create as a subclass of ioexception.
new to java development .
Hope someone can guide me on the right path.
thank u
Ritu.
 
author and jackaroo
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Hi Ritu
Welcome to JavaRanch


1. do i have to create new recordnotfoundexception.


You probably have an instruction to the effect of "Any unimplemented exceptions in this interface must all be created as member classes of the suncertify.db package."
So, yes you do have to create the RecordNotFound exception.


2. if yes for que 1 . where ( is my taught right ) to create as a subclass of ioexception.


I think that is reasonable.
Regards, Andrew
 
ritu ko
Greenhorn
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thanks andrew.
ritu
 
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Ritu:
2. if yes for que 1 . where ( is my taught right ) to create as a subclass of ioexception.
Andrew:
I think that is reasonable.

I wouldn't do that. "RecordNotFoundException" simply must tell the caller that the specified record does not exist. It's quite different from an IO issue IMO. So I would extend Exception instead.
Best,
Phil.
 
town drunk
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I completely agree. Please check this thread.
M
 
ritu ko
Greenhorn
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Thanks all for your help.
ritu.
 
Consider Paul's rocket mass heater.
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