net.hasor.db.datasource.ConnectionHolder Maven / Gradle / Ivy
/*
* Copyright 2008-2009 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.hasor.db.datasource;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Savepoint;
/**
*
* @version : 2014-3-29
* @author 赵永春 ([email protected])
*/
public class ConnectionHolder implements SavepointManager, ConnectionManager {
private int referenceCount;
private final DataSource dataSource;
private Connection connection;
ConnectionHolder(final DataSource dataSource) {
this.dataSource = dataSource;
}
public synchronized void requested() {
this.referenceCount++;
}
public synchronized void released() throws SQLException {
this.referenceCount--;
if (!this.isOpen() && this.connection != null) {
try {
this.savepointCounter = 0;
this.savepointSupported = null;
this.connection.close();
} finally {
this.connection = null;
}
}
}
public synchronized Connection getConnection() throws SQLException {
if (!this.isOpen()) {
return null;
}
if (this.connection == null) {
this.connection = this.dataSource.getConnection();
}
return this.connection;
}
public boolean isOpen() {
return this.referenceCount != 0;
}
/**则表示当前数据库连接是否有被引用。*/
public DataSource getDataSource() {
return dataSource;
}
/**是否存在事务*/
public boolean hasTransaction() throws SQLException {
Connection conn = this.getConnection();
if (conn == null) {
return false;
}
//AutoCommit被标记为 false 表示开启了事务。
return !conn.getAutoCommit();
}
/** 设置事务状态 */
public void setTransaction() throws SQLException {
Connection conn = this.getConnection();
if (conn != null && conn.getAutoCommit()) {
conn.setAutoCommit(false);
}
}
/** 取消事务状态,设置为自动递交 */
public void cancelTransaction() throws SQLException {
Connection conn = this.getConnection();
if (conn != null && !conn.getAutoCommit()) {
conn.setAutoCommit(true);
}
}
//---------------------------------------------------------------------------Savepoint
private Connection checkConn(final Connection conn) throws SQLException {
if (conn == null) {
throw new SQLException("Connection is null.");
}
return conn;
}
private static final String SAVEPOINT_NAME_PREFIX = "SAVEPOINT_";
private int savepointCounter = 0;
private Boolean savepointSupported;
/**使用一个全新的名称创建一个保存点。*/
@Override
public Savepoint createSavepoint() throws SQLException {
Connection conn = this.checkConn(this.getConnection());
this.savepointCounter++;
return conn.setSavepoint(ConnectionHolder.SAVEPOINT_NAME_PREFIX + this.savepointCounter);
}
@Override
public void rollbackToSavepoint(final Savepoint savepoint) throws SQLException {
Connection conn = this.checkConn(this.getConnection());
conn.rollback(savepoint);
}
@Override
public void releaseSavepoint(final Savepoint savepoint) throws SQLException {
Connection conn = this.checkConn(this.getConnection());
conn.releaseSavepoint(savepoint);
}
@Override
public boolean supportSavepoint() throws SQLException {
Connection conn = this.checkConn(this.getConnection());
if (this.savepointSupported == null) {
this.savepointSupported = conn.getMetaData().supportsSavepoints();
}
return this.savepointSupported;
}
}