package at.gv.egovernment.moa.spss.server.util;
import java.util.Set;
/**
* Generate unique ID values for various objects in the response.
*
* @author Patrick Peck
* @version $Id$
*/
public class IdGenerator {
/** The base value to append the counter to. */
private String base;
/** The Set
of reserved ID values. */
private Set reserved;
/** The sequence number. */
private int count;
/**
* Create a new IdGenerator
.
*
* @param base A base value to append the IDs to. The creator of this object
* should provide a base value, so that appending the counter leads to unique
* IDs.
* @param reserved The Set
of reserved IDs. A call to
* uniqueId()
will respect the reserved IDs.
*/
public IdGenerator(String base, Set reserved) {
this.base = base;
this.reserved = reserved;
count = 1;
}
/**
* Create the next ID value in the sequence.
*
* @return The next ID value in the sequence.
*/
public String nextId() {
return base + "-" + count++;
}
/**
* Create the next unique ID value which is unique in the reserved ID set.
*
* The created ID is added to the set of reserved IDs.
*
* @return The next ID value.
*/
public String uniqueId() {
String nextId;
while (reserved.contains(nextId = nextId()));
reserved.add(nextId);
return nextId;
}
}