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 *  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 org.sqlite;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import javax.sql.ConnectionEvent;
import javax.sql.ConnectionEventListener;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
import org.sqlite.javax.SQLiteConnectionPoolDataSource;

public class SQLiteConnectionPoolDataSourceTest {

    @Test
    public void connectionTest() throws SQLException {
        ConnectionPoolDataSource ds = new SQLiteConnectionPoolDataSource();

        PooledConnection pooledConn = ds.getPooledConnection();

        Connection handle = pooledConn.getConnection();
        assertThat(handle.isClosed()).isFalse();
        assertThat(handle.createStatement().execute("select 1")).isTrue();

        Connection handle2 = pooledConn.getConnection();
        assertThat(handle.isClosed()).isTrue();
        Connection finalHandle = handle;
        assertThatThrownBy(() -> finalHandle.createStatement().execute("select 1"))
                .isInstanceOf(SQLException.class)
                .hasMessage("Connection is closed");

        assertThat(handle2.createStatement().execute("select 1")).isTrue();
        handle2.close();

        handle = pooledConn.getConnection();
        assertThat(handle.createStatement().execute("select 1")).isTrue();

        pooledConn.close();
        assertThat(handle.isClosed()).isTrue();
    }

    /**
     * When a handle is closed the physical connection must be reset (rollback + auto-commit) before
     * the pool is notified, otherwise a concurrent borrower can reuse the physical connection while
     * the reset is still running. See issue #821.
     */
    @Test
    public void concurrentReuseDoesNotRaceOnClose() throws Exception {
        SQLiteConnectionPoolDataSource ds = new SQLiteConnectionPoolDataSource();
        ds.setUrl("jdbc:sqlite::memory:");

        DummyPool pool = new DummyPool(ds);
        AtomicReference<Throwable> failure = new AtomicReference<>();

        List<Thread> threads = new ArrayList<>();
        for (int i = 0; i < 8; i++) {
            Thread t =
                    new Thread(
                            () -> {
                                for (int j = 0; j < 2000 && failure.get() == null; j++) {
                                    try (Connection c = pool.getConnection()) {
                                        c.setAutoCommit(false);
                                        c.createStatement().execute("select 1");
                                    } catch (Throwable e) {
                                        failure.compareAndSet(null, e);
                                    }
                                }
                            });
            threads.add(t);
            t.start();
        }
        for (Thread t : threads) {
            t.join();
        }

        assertThat(failure.get()).isNull();
    }

    /** Minimal pool that hands out and takes back pooled connections, like a real pool would. */
    private static class DummyPool implements ConnectionEventListener {
        private final List<PooledConnection> available = new ArrayList<>();
        private final ConnectionPoolDataSource dataSource;

        DummyPool(ConnectionPoolDataSource dataSource) {
            this.dataSource = dataSource;
        }

        synchronized Connection getConnection() throws SQLException {
            Iterator<PooledConnection> it = available.iterator();
            PooledConnection pooled;
            if (it.hasNext()) {
                pooled = it.next();
                it.remove();
            } else {
                pooled = dataSource.getPooledConnection();
                pooled.addConnectionEventListener(this);
            }
            return pooled.getConnection();
        }

        @Override
        public synchronized void connectionClosed(ConnectionEvent event) {
            available.add((PooledConnection) event.getSource());
        }

        @Override
        public void connectionErrorOccurred(ConnectionEvent event) {}
    }

    @Disabled
    @Test
    public void proxyConnectionCloseTest() throws SQLException {
        ConnectionPoolDataSource ds = new SQLiteConnectionPoolDataSource();
        PooledConnection pooledConn = ds.getPooledConnection();
        System.out.println("pooledConn: " + pooledConn.getClass());

        Connection handle = pooledConn.getConnection();
        System.out.println("pooledConn.getConnection: " + handle.getClass());

        Statement st = handle.createStatement();
        System.out.println("statement: " + st.getClass());
        Connection stConn = handle.createStatement().getConnection();
        System.out.println("statement connection:" + stConn.getClass());
        stConn.close(); // This closes the physical connection, not the proxy

        Connection handle2 = pooledConn.getConnection();
    }
}
