001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.dbcp2;
018
019import java.io.PrintWriter;
020import java.sql.Connection;
021import java.sql.SQLException;
022import java.sql.SQLFeatureNotSupportedException;
023import java.util.NoSuchElementException;
024import java.util.Objects;
025import java.util.logging.Logger;
026
027import javax.sql.DataSource;
028
029import org.apache.commons.logging.Log;
030import org.apache.commons.logging.LogFactory;
031import org.apache.commons.pool2.ObjectPool;
032import org.apache.commons.pool2.impl.GenericObjectPool;
033
034/**
035 * A simple {@link DataSource} implementation that obtains {@link Connection}s from the specified {@link ObjectPool}.
036 *
037 * @param <C>
038 *            The connection type
039 *
040 * @since 2.0
041 */
042public class PoolingDataSource<C extends Connection> implements DataSource, AutoCloseable {
043
044    /**
045     * PoolGuardConnectionWrapper is a Connection wrapper that makes sure a closed connection cannot be used anymore.
046     *
047     * @since 2.0
048     */
049    private final class PoolGuardConnectionWrapper<D extends Connection> extends DelegatingConnection<D> {
050
051        PoolGuardConnectionWrapper(final D delegate) {
052            super(delegate);
053        }
054
055        @Override
056        public void close() throws SQLException {
057            if (getDelegateInternal() != null) {
058                super.close();
059                super.setDelegate(null);
060            }
061        }
062
063        /**
064         * @see org.apache.commons.dbcp2.DelegatingConnection#getDelegate()
065         */
066        @Override
067        public D getDelegate() {
068            return isAccessToUnderlyingConnectionAllowed() ? super.getDelegate() : null;
069        }
070
071        /**
072         * @see org.apache.commons.dbcp2.DelegatingConnection#getInnermostDelegate()
073         */
074        @Override
075        public Connection getInnermostDelegate() {
076            return isAccessToUnderlyingConnectionAllowed() ? super.getInnermostDelegate() : null;
077        }
078
079        @Override
080        public boolean isClosed() throws SQLException {
081            return getDelegateInternal() == null || super.isClosed();
082        }
083    }
084
085    private static final Log log = LogFactory.getLog(PoolingDataSource.class);
086
087    /** Controls access to the underlying connection */
088    private boolean accessToUnderlyingConnectionAllowed;
089
090    /** My log writer. */
091    private PrintWriter logWriter;
092
093    private final ObjectPool<C> pool;
094
095    /**
096     * Constructs a new instance backed by the given connection pool.
097     *
098     * @param pool
099     *            the given connection pool.
100     */
101    public PoolingDataSource(final ObjectPool<C> pool) {
102        Objects.requireNonNull(pool, "Pool must not be null.");
103        this.pool = pool;
104        // Verify that pool's factory refers back to it. If not, log a warning and try to fix.
105        if (this.pool instanceof GenericObjectPool<?>) {
106            final PoolableConnectionFactory pcf = (PoolableConnectionFactory) ((GenericObjectPool<?>) this.pool)
107                    .getFactory();
108            Objects.requireNonNull(pcf, "PoolableConnectionFactory must not be null.");
109            if (pcf.getPool() != this.pool) {
110                log.warn(Utils.getMessage("poolingDataSource.factoryConfig"));
111                @SuppressWarnings("unchecked") // PCF must have a pool of PCs
112                final ObjectPool<PoolableConnection> p = (ObjectPool<PoolableConnection>) this.pool;
113                pcf.setPool(p);
114            }
115        }
116    }
117
118    /**
119     * Closes and free all {@link Connection}s from the pool.
120     *
121     * @since 2.1
122     */
123    @Override
124    public void close() throws SQLException {
125        try {
126            pool.close();
127        } catch (final Exception e) {
128            throw new SQLException(Utils.getMessage("pool.close.fail"), e);
129        }
130    }
131
132    /**
133     * Returns a {@link java.sql.Connection} from my pool, according to the contract specified by
134     * {@link ObjectPool#borrowObject}.
135     */
136    @Override
137    public Connection getConnection() throws SQLException {
138        try {
139            final C conn = pool.borrowObject();
140            if (conn == null) {
141                return null;
142            }
143            return new PoolGuardConnectionWrapper<>(conn);
144        } catch (final NoSuchElementException e) {
145            throw new SQLException("Cannot get a connection, pool error " + e.getMessage(), e);
146        } catch (final SQLException | RuntimeException e) {
147            throw e;
148        } catch (final InterruptedException e) {
149            // Reset the interrupt status so it is visible to callers
150            Thread.currentThread().interrupt();
151            throw new SQLException("Cannot get a connection, general error", e);
152        } catch (final Exception e) {
153            throw new SQLException("Cannot get a connection, general error", e);
154        }
155    }
156
157    /**
158     * Throws {@link UnsupportedOperationException}
159     *
160     * @throws UnsupportedOperationException
161     *             always thrown
162     */
163    @Override
164    public Connection getConnection(final String userName, final String password) throws SQLException {
165        throw new UnsupportedOperationException();
166    }
167
168    // --- DataSource methods -----------------------------------------
169
170    /**
171     * Throws {@link UnsupportedOperationException}.
172     *
173     * @throws UnsupportedOperationException
174     *             As this implementation does not support this feature.
175     */
176    @Override
177    public int getLoginTimeout() {
178        throw new UnsupportedOperationException("Login timeout is not supported.");
179    }
180
181    /**
182     * Returns my log writer.
183     *
184     * @return my log writer
185     * @see DataSource#getLogWriter
186     */
187    @Override
188    public PrintWriter getLogWriter() {
189        return logWriter;
190    }
191
192    @Override
193    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
194        throw new SQLFeatureNotSupportedException();
195    }
196
197    protected ObjectPool<C> getPool() {
198        return pool;
199    }
200
201    /**
202     * Returns the value of the accessToUnderlyingConnectionAllowed property.
203     *
204     * @return true if access to the underlying {@link Connection} is allowed, false otherwise.
205     */
206    public boolean isAccessToUnderlyingConnectionAllowed() {
207        return this.accessToUnderlyingConnectionAllowed;
208    }
209
210    @Override
211    public boolean isWrapperFor(final Class<?> iface) throws SQLException {
212        return iface != null && iface.isInstance(this);
213    }
214
215    /**
216     * Sets the value of the accessToUnderlyingConnectionAllowed property. It controls if the PoolGuard allows access to
217     * the underlying connection. (Default: false)
218     *
219     * @param allow
220     *            Access to the underlying connection is granted when true.
221     */
222    public void setAccessToUnderlyingConnectionAllowed(final boolean allow) {
223        this.accessToUnderlyingConnectionAllowed = allow;
224    }
225
226    /**
227     * Throws {@link UnsupportedOperationException}.
228     *
229     * @throws UnsupportedOperationException
230     *             As this implementation does not support this feature.
231     */
232    @Override
233    public void setLoginTimeout(final int seconds) {
234        throw new UnsupportedOperationException("Login timeout is not supported.");
235    }
236
237    /**
238     * Sets my log writer.
239     *
240     * @see DataSource#setLogWriter
241     */
242    @Override
243    public void setLogWriter(final PrintWriter out) {
244        logWriter = out;
245    }
246
247    @Override
248    public <T> T unwrap(final Class<T> iface) throws SQLException {
249        if (isWrapperFor(iface)) {
250            return iface.cast(this);
251        }
252        throw new SQLException(this + " is not a wrapper for " + iface);
253    }
254}