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/* * Copyright 2002-2018 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 * * https://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 org.springframework.jdbc.datasource; import java.sql.Connection; import java.sql.SQLException; import java.sql.Savepoint; import org.springframework.lang.Nullable; import org.springframework.transaction.support.ResourceHolderSupport; import org.springframework.util.Assert; /** * Resource holder wrapping a JDBC {@link Connection}. * {@link DataSourceTransactionManager} binds instances of this class * to the thread, for a specific {@link javax.sql.DataSource}. * * <p>Inherits rollback-only support for nested JDBC transactions * and reference count functionality from the base class. * * <p>Note: This is an SPI class, not intended to be used by applications. * * @author Juergen Hoeller * @since 06.05.2003 * @see DataSourceTransactionManager * @see DataSourceUtils */ public class ConnectionHolder extends ResourceHolderSupport { /** * Prefix for savepoint names. */ public static final String SAVEPOINT_NAME_PREFIX = "SAVEPOINT_"; @Nullable private ConnectionHandle connectionHandle; @Nullable private Connection currentConnection; private boolean transactionActive = false; @Nullable private Boolean savepointsSupported; private int savepointCounter = 0; /** * Create a new ConnectionHolder for the given ConnectionHandle. * @param connectionHandle the ConnectionHandle to hold */ public ConnectionHolder(ConnectionHandle connectionHandle) { Assert.notNull(connectionHandle, "ConnectionHandle must not be null"); this.connectionHandle = connectionHandle; } /** * Create a new ConnectionHolder for the given JDBC Connection, * wrapping it with a {@link SimpleConnectionHandle}, * assuming that there is no ongoing transaction. * @param connection the JDBC Connection to hold * @see SimpleConnectionHandle * @see #ConnectionHolder(java.sql.Connection, boolean) */ public ConnectionHolder(Connection connection) { this.connectionHandle = new SimpleConnectionHandle(connection); } /** * Create a new ConnectionHolder for the given JDBC Connection, * wrapping it with a {@link SimpleConnectionHandle}. * @param connection the JDBC Connection to hold * @param transactionActive whether the given Connection is involved * in an ongoing transaction * @see SimpleConnectionHandle */ public ConnectionHolder(Connection connection, boolean transactionActive) { this(connection); this.transactionActive = transactionActive; } /** * Return the ConnectionHandle held by this ConnectionHolder. */ @Nullable public ConnectionHandle getConnectionHandle() { return this.connectionHandle; } /** * Return whether this holder currently has a Connection. */ protected boolean hasConnection() { return (this.connectionHandle != null); } /** * Set whether this holder represents an active, JDBC-managed transaction. * @see DataSourceTransactionManager */ protected void setTransactionActive(boolean transactionActive) { this.transactionActive = transactionActive; } /** * Return whether this holder represents an active, JDBC-managed transaction. */ protected boolean isTransactionActive() { return this.transactionActive; } /** * Override the existing Connection handle with the given Connection. * Reset the handle if given {@code null}. * <p>Used for releasing the Connection on suspend (with a {@code null} * argument) and setting a fresh Connection on resume. */ protected void setConnection(@Nullable Connection connection) { if (this.currentConnection != null) { if (this.connectionHandle != null) { this.connectionHandle.releaseConnection(this.currentConnection); } this.currentConnection = null; } if (connection != null) { this.connectionHandle = new SimpleConnectionHandle(connection); } else { this.connectionHandle = null; } } /** * Return the current Connection held by this ConnectionHolder. * <p>This will be the same Connection until {@code released} * gets called on the ConnectionHolder, which will reset the * held Connection, fetching a new Connection on demand. * @see ConnectionHandle#getConnection() * @see #released() */ public Connection getConnection() { Assert.notNull(this.connectionHandle, "Active Connection is required"); if (this.currentConnection == null) { this.currentConnection = this.connectionHandle.getConnection(); } return this.currentConnection; } /** * Return whether JDBC 3.0 Savepoints are supported. * Caches the flag for the lifetime of this ConnectionHolder. * @throws SQLException if thrown by the JDBC driver */ public boolean supportsSavepoints() throws SQLException { if (this.savepointsSupported == null) { this.savepointsSupported = getConnection().getMetaData().supportsSavepoints(); } return this.savepointsSupported; } /** * Create a new JDBC 3.0 Savepoint for the current Connection, * using generated savepoint names that are unique for the Connection. * @return the new Savepoint * @throws SQLException if thrown by the JDBC driver */ public Savepoint createSavepoint() throws SQLException { this.savepointCounter++; return getConnection().setSavepoint(SAVEPOINT_NAME_PREFIX + this.savepointCounter); } /** * Releases the current Connection held by this ConnectionHolder. * <p>This is necessary for ConnectionHandles that expect "Connection borrowing", * where each returned Connection is only temporarily leased and needs to be * returned once the data operation is done, to make the Connection available * for other operations within the same transaction. */ @Override public void released() { super.released(); if (!isOpen() && this.currentConnection != null) { if (this.connectionHandle != null) { this.connectionHandle.releaseConnection(this.currentConnection); } this.currentConnection = null; } } @Override public void clear() { super.clear(); this.transactionActive = false; this.savepointsSupported = null; this.savepointCounter = 0; } }