package jef.database;
import java.sql.SQLException;
import java.util.Collections;
import java.util.HashMap;
import javax.persistence.GenerationType;
import javax.persistence.PersistenceException;
import javax.persistence.SequenceGenerator;
import javax.persistence.TableGenerator;
import jef.database.DbMetaData.ObjectType;
import jef.database.annotation.HiloGeneration;
import jef.database.dialect.ColumnType;
import jef.database.dialect.ColumnType.AutoIncrement;
import jef.database.dialect.DatabaseDialect;
import jef.database.dialect.type.AutoIncrementMapping;
import jef.database.dialect.type.AutoIncrementMapping.GenerationResolution;
import jef.database.jdbc.result.IResultSet;
import jef.database.meta.AbstractSequence;
import jef.database.meta.Feature;
import jef.database.meta.TupleMetadata;
import jef.database.wrapper.populator.AbstractResultSetTransformer;
import jef.database.wrapper.populator.ResultSetExtractor;
import jef.tools.Assert;
import jef.tools.JefConfiguration;
import jef.tools.StringUtils;
/**
* Sequence管理接口。
*
* @author jiyi
*
*/
public final class SequenceManager {
private final HashMap<String, Sequence> holders = new HashMap<String, Sequence>();
private boolean hiloFlag = JefConfiguration.getBoolean(DbCfg.DB_AUTOINCREMENT_HILO, false);
private DbClient parent;
/**
* 建sequence时对表名长度的限制，因为默认的seq名是:表名_SEQ 数据库对sequence名字长度的限制是30
*/
protected SequenceManager(DbClient parent) {
this.parent = parent;
}
/**
* 获取Sequence，无论什么数据库都可以获取Sequence。如果是原生支持Sequence的数据库，会返回原生的实现；如果非原生支持，
* 会返回用数据表的模拟实现。
*
* @param seqName
* @param client
* @return
* @throws SQLException
*/
public Sequence getSequence(AutoIncrementMapping fieldDef, OperateTarget client) throws SQLException {
if (fieldDef == null)
return null;
String name = fieldDef.getSequenceName(client.getProfile());
Sequence s = holders.get(name);
if (s == null) {
synchronized (holders) {
s = holders.get(name);
if (s == null) {// 双重检查锁定: 防止被多线程的情况下初始化多次
DatabaseDialect profile = client.getProfile();
AutoIncrement a = (AutoIncrement) fieldDef.get();
GenerationType type = a.getGenerationType(profile, false);
// 绑定DataSource
String datasource = fieldDef.getSequenceDataSource(profile);
if (datasource != null) {// 必须绑定DataSource
client = (OperateTarget) client.getSession().getSqlTemplate(StringUtils.trimToNull(datasource));
}
String columnName = fieldDef.getColumnName(profile, true);
if (type == GenerationType.SEQUENCE) {
s = createSequence(name, client, a.getPrecision(), fieldDef.getMeta().getTableName(true), columnName, a.getSeqGenerator());
} else if (type == GenerationType.TABLE) {
s = createTable(name, client, a.getPrecision(), fieldDef.getMeta().getTableName(true), columnName, a.getTableGenerator());
}
holders.put(name, wrapForHilo((AbstractSequence) s, a.getHiloConfig()));
}
}
}
return s;
}
/**
* 获取Sequence，无论什么数据库都可以获取Sequence。如果是原生支持Sequence的数据库，会返回原生的实现；如果非原生支持，
* 会返回用数据表的模拟实现。
*
* @param fieldDef
* @param dbKey
* @return
* @throws SQLException
*/
public Sequence getSequence(AutoIncrementMapping fieldDef, String dbKey) throws SQLException {
return getSequence(fieldDef, parent.selectTarget(dbKey));
}
/**
* 获取Sequence，无论什么数据库都可以获取Sequence。如果是原生支持Sequence的数据库，会返回原生的实现；如果非原生支持，
* 会返回用数据表的模拟实现。
*
* @param seqName
* @param client
* @param length
* @return
* @throws SQLException
*/
public Sequence getSequence(String seqName, OperateTarget client, int length) throws SQLException {
Sequence s = holders.get(seqName);
if (s == null) {
synchronized (holders) {
s = holders.get(seqName);
if (s == null) {// 双重检查锁定: 防止被多线程的情况下初始化多次
if (client == null) {
client = this.parent.selectTarget(null);
}
if (client.getProfile().has(Feature.SUPPORT_SEQUENCE)) {
s = createSequence(seqName, client, length, null, null, null);
} else {
s = createTable(seqName, client, length, null, null, null);
}
holders.put(seqName, s);
}
}
}
return s;
}
/**
* 删除Sequence
*
* @param mapping
* @param meta
* @throws SQLException
*/
public void dropSequence(AutoIncrementMapping mapping, OperateTarget meta) throws SQLException {
DatabaseDialect profile = meta.getProfile();
GenerationResolution type = mapping.getGenerationType(profile);
String datasource = mapping.getSequenceDataSource(profile);
if (datasource != null) {// 必须绑定DataSource
meta = (OperateTarget) meta.getSession().getSqlTemplate(StringUtils.trimToNull(datasource));
}
String name = mapping.getSequenceName(profile);
if (type == GenerationResolution.SEQUENCE) {
meta.getMetaData().dropSequence(name);
} else if (type == GenerationResolution.TABLE) {
String pname = JefConfiguration.get(DbCfg.DB_GLOBAL_SEQUENCE_TABLE);
if (StringUtils.isEmpty(pname)) {
meta.getMetaData().dropTable(name);
} else {
removeRecordInSeqTable(pname.trim(), name, meta);
}
}
}
/**
* must clean cache on junit 4 tests....
*/
public void clearHolders() {
for (Sequence s : holders.values()) {
s.clear();
}
holders.clear();
}
private static boolean removeRecordInSeqTable(String table, String key, OperateTarget sqlTemplate) throws SQLException {
if (StringUtils.isEmpty(table) || StringUtils.isEmpty(key)) {
throw new IllegalArgumentException();
}
table = sqlTemplate.getMetaData().getExists(ObjectType.TABLE, table);
if (table != null) {
String sql = "delete from " + table + " where T=?";
int i = sqlTemplate.executeSql(sql, key);
return i > 0;
}
return false;
}
private Sequence wrapForHilo(AbstractSequence s, HiloGeneration hilo) {
if (hilo != null && hilo.maxLo() > 1) {
if (hiloFlag || hilo.always()) {
if (s instanceof AbstractSequence) {// 减少Cache大小
AbstractSequence as = (AbstractSequence) s;
as.setCacheSize(as.getCacheSize() / hilo.maxLo());
}
s = new SequenceHiloGenerator(s, hilo.maxLo());
}
}
return s;
}
private Sequence createTable(String name, OperateTarget client, int length, String tableName, String columnName, TableGenerator config) {
String pname = JefConfiguration.get(DbCfg.DB_GLOBAL_SEQUENCE_TABLE);
if (StringUtils.isEmpty(pname)) {
return new SeqTableImpl(client, name, config, tableName, columnName, this);
} else {
return new AdvSeqTableImpl(client, name, config, tableName, columnName, this);
}
}
private Sequence createSequence(String seqName, OperateTarget client, int columnSize, String tableName, String columnName, SequenceGenerator config) throws SQLException {
int initValue = 1;
if (config != null) {
seqName = config.sequenceName();
initValue = config.initialValue();
if (StringUtils.isNotEmpty(config.schema())) {
seqName = config.schema().trim() + "." + seqName;
}
}
return new SequenceNativeImpl(seqName, client, columnSize, tableName, columnName, initValue, this);
}
/**
* 第一种SQL实现，每个Sequence一张表
*/
private static final class SeqTableImpl extends AbstractSequence {
static TupleMetadata seqtable;
static {
seqtable = new TupleMetadata("SEQ");
seqtable.addColumn("V", new ColumnType.Int(12));
}
private int valueStep;
private String table;
private String rawTable;
private String rawColumn;
private int initValue;
private long last = -1;
private String update;
private String select;
/*
* @param rawSeqName Sequence表名称
*
* @param tableName 表名
*
* @param columnName 列名
*
* @throws SQLException
*/
SeqTableImpl(OperateTarget target, String seqTable, TableGenerator config, String rawTableName, String rawColumnName, SequenceManager parent) {
super(target, parent);
Assert.notNull(target);
this.table = seqTable;
this.rawTable = rawTableName;
this.rawColumn = rawColumnName;
if (config != null)
this.initValue = config.initialValue();
String valueColumn = config == null ? "V" : config.valueColumnName();
this.update = "UPDATE " + table + " SET " + valueColumn + "=? WHERE " + valueColumn + "=?";
this.select = "SELECT " + valueColumn + " FROM " + table;
this.valueStep = JefConfiguration.getInt(DbCfg.SEQUENCE_BATCH_SIZE, 20);// 每次取一批
if (valueStep < 1)
valueStep = config == null ? 20 : config.allocationSize();
if (target != null) {
tryInit();
}
}
@Override
protected long getFirstAndPushOthers(int num, DbClient conn, String dbKey) throws SQLException {
DbMetaData meta = conn.getMetaData(dbKey);
if (last < 0) {
last = queryLast(meta);
}
long nextVal = last + valueStep;
int updated = conn.executeSql(update, nextVal, last);
while (updated == 0) { // 基于CAS操作的乐观锁,
last = queryLast(meta);
nextVal = last + valueStep;
updated = conn.executeSql(update, nextVal, last);
}
long result = last + 1;
super.pushRange(last + 2, nextVal);
last = nextVal;
return result;
}
private long queryLast(DbMetaData conn) throws SQLException {
long value = conn.selectBySql(select, GET_LONG_OR_TABLE_NOT_EXIST, 1, Collections.EMPTY_LIST);
if (value == -9999L) {
long start = super.caclStartValue(conn, null, rawTable, rawColumn, initValue, 99999999999L);
conn.executeSql("INSERT INTO " + table + " VALUES(?)", start);
value = 0;
}
return value;
}
public boolean isTable() {
return true;
}
public String getName() {
return table;
}
@Override
protected boolean doInit(DbClient session, String dbKey) throws SQLException {
DbMetaData meta = session.getMetaData(dbKey);
String tableExists = meta.getExists(ObjectType.TABLE, table);
if (tableExists == null) {
if (ORMConfig.getInstance().isAutoCreateSequence()) {
int start = 0;
meta.createTable(seqtable, table);
meta.executeSql("INSERT INTO " + this.table + " VALUES(?)", start);
} else {
throw new PersistenceException("Table for sequence " + table + " does not exist on " + meta + "!");
}
}else{
this.table=tableExists;
}
return true;
}
public boolean isRawNative() {
return false;
}
}
/**
* 第二种SQL实现，所有Sequence公用一张表
*/
private static final class AdvSeqTableImpl extends AbstractSequence {
static String publicTableName = StringUtils.trimToNull(JefConfiguration.get(DbCfg.DB_GLOBAL_SEQUENCE_TABLE, "JEF_SEQUENCES"));
static TupleMetadata seqtable;
static {
seqtable = new TupleMetadata(publicTableName);
seqtable.addColumn("V", new ColumnType.Int(12));
seqtable.addColumn("T", "T", new ColumnType.Varchar(64), true);
}
private String table;
private String key;
private int valueStep;
private String rawTable;
private String rawColumn;
private int initValue;
private String update;
private String select;
private long last = -1;
/*
* @param key Sequence名称
*
* @param tableName 表名
*/
AdvSeqTableImpl(OperateTarget target, String key, TableGenerator config, String rawTable, String rawColumn, SequenceManager parent) {
super(target, parent);
Assert.notNull(target);
this.table = publicTableName;
this.key = key;
this.rawTable = rawTable;
this.rawColumn = rawColumn;
this.initValue = config == null ? 0 : config.initialValue();
this.valueStep = JefConfiguration.getInt(DbCfg.SEQUENCE_BATCH_SIZE, 20);
if (valueStep < 1)
valueStep = 20;
this.update = "UPDATE " + table + " SET V=? WHERE V=? AND T='" + key + "'";
this.select = "SELECT V FROM " + table + " WHERE T='" + key + "'";
if (target != null) {
tryInit();
}
}
@Override
protected long getFirstAndPushOthers(int num, DbClient conn, String dbKey) throws SQLException {
DbMetaData meta = conn.getNoTransactionSession().getMetaData(dbKey);
if (last < 0) {
last = queryLast(meta);
}
long nextVal = last + valueStep;
int updated = conn.executeSql(update, nextVal, last);
while (updated == 0) { // 基于CAS操作的乐观锁,
last = queryLast(meta);
nextVal = last + valueStep;
updated = conn.executeSql(update, nextVal, last);
}
long result = last + 1;
super.pushRange(last + 2, nextVal);
last = nextVal;
return result;
}
private long queryLast(DbMetaData conn) throws SQLException {
long value = conn.selectBySql(select, GET_LONG_OR_TABLE_NOT_EXIST, 1, Collections.EMPTY_LIST);
if (value == -9999L) {
long start = super.caclStartValue(conn, null, rawTable, rawColumn, initValue, 99999999999L);
conn.executeSql("INSERT INTO " + table + "(V,T) VALUES(?,?)", start, key);
value = 0;
}
return value;
}
public boolean isTable() {
return true;
}
public String getName() {
return key;
}
@Override
protected boolean doInit(DbClient session, String dbKey) throws SQLException {
DbMetaData meta = session.getMetaData(dbKey);
String exists=meta.getExists(ObjectType.TABLE, this.table);
if (exists==null) {
if (ORMConfig.getInstance().isAutoCreateSequence()) {
meta.createTable(seqtable, table);
} else {
throw new PersistenceException("Table for sequence " + table + " does not exist on " + meta + "!");
}
}else{
this.table=exists;
}
return true;
}
public boolean isRawNative() {
return false;
}
}
/**
* 从结果中获得单个LONG值
*/
private static final ResultSetExtractor<Long> GET_LONG_OR_TABLE_NOT_EXIST = new AbstractResultSetTransformer<Long>() {
public Long transformer(IResultSet rs) throws SQLException {
if (rs.next()) {
return rs.getLong(1);
} else {
return -9999L;
}
}
};
public void close() {
this.clearHolders();
}
}