org.hibernate.id: public class: TableHiLoGenerator

org.hibernate.id
public class: TableHiLoGenerator [javadoc | source]

java.lang.Object
   org.hibernate.engine.TransactionHelper
      org.hibernate.id.TableGenerator
         org.hibernate.id.TableHiLoGenerator

All Implemented Interfaces:
Configurable, PersistentIdentifierGenerator

hilo

An IdentifierGenerator that returns a Long, constructed using a hi/lo algorithm. The hi value MUST be fetched in a seperate transaction to the Session transaction so the generator must be able to obtain a new connection and commit it. Hence this implementation may not be used when the user is supplying connections. In this case a SequenceHiLoGenerator would be a better choice (where supported).

Mapping parameters supported: table, column, max_lo

Also see:

SequenceHiLoGenerator

author: Gavin - King

Field Summary
public static final String	MAX_LO	The max_lo parameter

Fields inherited from org.hibernate.id.TableGenerator:
COLUMN, DEFAULT_COLUMN_NAME, TABLE, DEFAULT_TABLE_NAME

Method from org.hibernate.id.TableHiLoGenerator Summary:
configure, generate

Methods from org.hibernate.id.TableGenerator:
configure, doWorkInCurrentTransaction, generate, generatorKey, sqlCreateStrings, sqlDropStrings

Methods from org.hibernate.engine.TransactionHelper:
doWorkInCurrentTransaction, doWorkInNewTransaction

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.hibernate.id.TableHiLoGenerator Detail:
public void configure(Type type, Properties params, Dialect d) { super.configure(type, params, d); maxLo = PropertiesHelper.getInt(MAX_LO, params, Short.MAX_VALUE); lo = maxLo + 1; // so we "clock over" on the first invocation returnClass = type.getReturnedClass(); }
public synchronized Serializable generate(SessionImplementor session, Object obj) throws HibernateException { if (maxLo < 1) { //keep the behavior consistent even for boundary usages long val = ( (Number) super.generate(session, obj) ).longValue(); if (val == 0) val = ( (Number) super.generate(session, obj) ).longValue(); return IdentifierGeneratorFactory.createNumber( val, returnClass ); } if (lo >maxLo) { long hival = ( (Number) super.generate(session, obj) ).longValue(); lo = (hival == 0) ? 1 : 0; hi = hival * (maxLo+1); log.debug("new hi value: " + hival); } return IdentifierGeneratorFactory.createNumber( hi + lo++, returnClass ); }

Method from org.hibernate.id.TableHiLoGenerator Detail:

 public  void configure(Type type,
    Properties params,
    Dialect d) {
	        
		super.configure(type, params, d);
		maxLo = PropertiesHelper.getInt(MAX_LO, params, Short.MAX_VALUE);
		lo = maxLo + 1; // so we "clock over" on the first invocation
		returnClass = type.getReturnedClass();
}

 public synchronized Serializable generate(SessionImplementor session,
    Object obj) throws HibernateException {
        if (maxLo <  1) {
			//keep the behavior consistent even for boundary usages
			long val = ( (Number) super.generate(session, obj) ).longValue();
			if (val == 0) val = ( (Number) super.generate(session, obj) ).longValue();
			return IdentifierGeneratorFactory.createNumber( val, returnClass );
		}
		if (lo >maxLo) {
			long hival = ( (Number) super.generate(session, obj) ).longValue();
			lo = (hival == 0) ? 1 : 0;
			hi = hival * (maxLo+1);
			log.debug("new hi value: " + hival);
		}
		return IdentifierGeneratorFactory.createNumber( hi + lo++, returnClass );
}