com.pactera.edg.am.metamanager.extractor.dao.impl.SequenceDaoImpl.java Source code

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Here is the source code for com.pactera.edg.am.metamanager.extractor.dao.impl.SequenceDaoImpl.java

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/*
 * Copyright 2011 by pactera.edg.am Corporation. Address:HePingLi East Street No.11
 * 5-5, BeiJing,
 * 
 * All rights reserved.
 * 
 * This software is the confidential and proprietary information of pactera.edg.am
 * Corporation ("Confidential Information"). You shall not disclose such
 * Confidential Information and shall use it only in accordance with the terms
 * of the license agreement you entered into with pactera.edg.am.
 */

package com.pactera.edg.am.metamanager.extractor.dao.impl;

import java.util.UUID;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

import com.pactera.edg.am.metamanager.core.components.uuid.FastUUIDGen;
import com.pactera.edg.am.metamanager.core.components.uuid.UUIDGen;
import com.pactera.edg.am.metamanager.core.components.uuid.UUIDGenFactory;
import com.pactera.edg.am.metamanager.extractor.dao.ISequenceDao;

/**
 * sequence?,,
 * 
 * @author hqchen
 * @version 1.0 Date: Jul 23, 2009
 * @author fbchen [add uuid gen method] 2010-07-30
 */
public class SequenceDaoImpl extends JdbcDaoSupport implements ISequenceDao {

    private static final String SEQUENCE_FLAG = "SEQ_";

    private static final Byte LOCK = 'L';

    private UUIDGen uuidGen;

    public SequenceDaoImpl() {
        super();
    }

    /* (non-Javadoc)
     * @see com.pactera.edg.am.metamanager.extractor.dao.ISequenceDao#getNextval(java.lang.String)
     */
    public long getNextval(String tableName) {
        String sequenceName = getSequenceName(tableName);
        return super.getJdbcTemplate().queryForLong(
                new StringBuilder("select ").append(sequenceName).append(".nextval from dual").toString());
    }

    private String getSequenceName(String tableName) {
        return (SEQUENCE_FLAG + tableName).toUpperCase();
    }

    /*
     * (non-Javadoc)
     * @see com.pactera.edg.am.metamanager.extractor.dao.ISequenceDao#getUuid()
     */
    public String getUuid() {
        StringBuffer uuid = new StringBuffer();
        try {
            uuid.append(UUID.randomUUID().toString());
        } catch (Exception e) {
            this.createUUIDGen();
            uuid.append(uuidGen.nextUUID());
        }
        if (uuid.length() == 0) {
            throw new RuntimeException("UUID generate fail");
        }
        uuid.setCharAt(0, shiftHex(uuid.charAt(0))); //hibernateuuid.hex??
        return uuid.toString().replaceAll("-", "");
    }

    /**
     * 16???16?0~9 => g~pa~f => q~vA~F => Q~V
     * @param c ?16
     * @return ??
     */
    private static char shiftHex(char c) {
        return (char) (c + (c <= '9' ? 55 : 16));
    }

    /**
     * UUID?????<br>
     * ??<ul>
     * <li>com.pactera.edg.am.metamanager.core.components.uuid.SimpleUUIDGen - ?</li>
     * <li>com.pactera.edg.am.metamanager.core.components.uuid.FastUUIDGen - ?</li>
     * </ul>
     */
    public void createUUIDGen() {
        if (uuidGen == null) {
            synchronized (LOCK) {
                if (uuidGen == null) {
                    uuidGen = UUIDGenFactory.getUUIDGen(FastUUIDGen.class);
                }
            }
        }
    }

}