package com.demo.persistence.impl;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Properties;

import org.hibernate.dialect.Dialect;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.AbstractUUIDGenerator;
import org.hibernate.id.Configurable;
import org.hibernate.type.Type;

/**
 * <b>uuid</b><br>
 * <br>
 * A <tt>custom UUID generator</tt> that returns a string from java.util.UUID,
 * This string will consist of only hex digits. Optionally,
 * the string may be generated with separators between each
 * component of the UUID.
 *
 * Mapping parameters supported: none
 *
 * @author wallacew
 */

public class CustomGeneratedId extends AbstractUUIDGenerator implements Configurable {

    // private String sep = "";
    /** Generate function. 
    * @param session Session handle
    * @param obj obj type
    * @return Serializable object
    */
    @SuppressWarnings("unused")
    public Serializable generate(SessionImplementor session, Object obj) {
        Serializable result = null;

        // if user has set the id manually, don't change it.        
        try {
            Class<?> clazz = obj.getClass();
            Method idMethod = clazz.getMethod("getId");
            result = (Serializable) idMethod.invoke(obj);
        } catch (Exception e) {
            // do nothing
        }
        
        if (result == null) {
            result = java.util.UUID.randomUUID().toString();
        }
        
        return result; 
    }

    /** Currently unused. 
    * @param type hibernate config 
    * @param params hibernate config 
    * @param d dialect to use
    */
    @SuppressWarnings("unused")
    public void configure(Type type, Properties params, Dialect d) {
        // sep = PropertiesHelper.getString("separator", params, "");
    }
}