org.moneta.healthcheck.DbcpConnectionPoolHealthCheck.java Source code

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Here is the source code for org.moneta.healthcheck.DbcpConnectionPoolHealthCheck.java

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/*
 * This software is licensed under the Apache License, Version 2.0
 * (the "License") agreement; 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.moneta.healthcheck;

import org.apache.commons.dbcp2.PoolableConnection;
import org.apache.commons.dbcp2.PoolableConnectionFactory;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.commons.lang3.Validate;
import org.apache.commons.pool2.impl.GenericObjectPool;

import com.codahale.metrics.health.HealthCheck;

/**
 * Will check the health of a database connection pool managed by Apache Commons
 * DBCP. Items checked are the following: <li>The number of threads waiting for
 * a connection isn't larger than a configurable threashold (default=3)</li> <li>
 * A connection from the pool does sucessfully validate.</li>
 * 
 * @author D. Ashmore
 *
 */
public class DbcpConnectionPoolHealthCheck extends HealthCheck {
    private final GenericObjectPool<PoolableConnection> connectionPool;
    private int maxWaitingConnections = 3;
    private final String poolName;

    public DbcpConnectionPoolHealthCheck(GenericObjectPool<PoolableConnection> pool, String poolName) {
        Validate.notNull(pool, "Null connection pool not allowed.");
        Validate.notEmpty(poolName, "Null or blank poolName not allowed.");
        Validate.isTrue(pool.getFactory() instanceof PoolableConnectionFactory,
                "this check only handles connection pools using PoolableConnectionFactory");
        connectionPool = pool;
        this.poolName = poolName;
        this.setMaxWaitingConnections(3);
    }

    @Override
    protected Result check() throws Exception {

        GenericObjectPool<PoolableConnection> pool = (GenericObjectPool<PoolableConnection>) connectionPool;
        if (pool.getNumWaiters() > maxWaitingConnections) {
            return Result.unhealthy(
                    "Overloaded connection pool.  name=" + poolName + " nbrWaiters=" + pool.getNumWaiters());
        }

        PoolableConnectionFactory poolFactory = (PoolableConnectionFactory) pool.getFactory();
        PoolableConnection conn = null;
        try {
            conn = pool.borrowObject();
            poolFactory.validateConnection(conn);
        } catch (Exception e) {
            return Result
                    .unhealthy("Database connection validation error.  error=" + ExceptionUtils.getStackTrace(e));
        } finally {
            DbUtils.closeQuietly(conn);
        }

        return Result.healthy();
    }

    public int getMaxWaitingConnections() {
        return maxWaitingConnections;
    }

    public void setMaxWaitingConnections(int maxWaitingConnections) {
        this.maxWaitingConnections = maxWaitingConnections;
    }

}