import org.apache.tomcat.jdbc.pool.JdbcInterceptor; //导入依赖的package包/类
private String lookupUrl() {
    if (url == null) {
        JdbcInterceptor interceptor = getNext();
        while (interceptor != null) {
            if (interceptor instanceof ProxyConnection) {
                url = getUrlFromConnectionPool(((ProxyConnection) interceptor).getPool());
                break;
            }
            interceptor = getNext();
        }
        if (url == null) {
            throw new IllegalStateException("url must not be null after looking up the chain");
        }
    }
    return url;
}
 

import org.apache.tomcat.jdbc.pool.JdbcInterceptor; //导入依赖的package包/类
public boolean resetTimer() {
    boolean result = false;
    JdbcInterceptor interceptor = this.getNext();
    while (interceptor!=null && result==false) {
        if (interceptor instanceof ProxyConnection) {
            PooledConnection con = ((ProxyConnection)interceptor).getConnection();
            if (con!=null) {
                con.setTimestamp(System.currentTimeMillis());
                result = true;
            } else {
                break;
            }
        }
        interceptor = interceptor.getNext();
    }
    return result;
}
 

import org.apache.tomcat.jdbc.pool.JdbcInterceptor; //导入依赖的package包/类
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    final String name = method.getName();
    boolean close = compare(JdbcInterceptor.CLOSE_VAL, name);
    if (close && closed) return null;
    if (compare(JdbcInterceptor.ISCLOSED_VAL, name)) {
        return closed;
    }
    if (closed) throw new SQLException("Statement closed.");
    boolean process = isExecute(method, false);
    StatementTracer tracer = getStatementTracer();
    Object result = null;
    Throwable error = null;
    try {
        if (process && tracer != null) {
            tracer.beginTrace(sql, lookupUrl());
        }
        result = method.invoke(delegate, args);
    } catch (Throwable t) {
        error = t;
        throw t;
    } finally {
        if (process && tracer != null) {
            tracer.endTrace(0, error);
        }
    }
    if (close) {
        closed = true;
        delegate = null;
    }
    return result;
}
 

import org.apache.tomcat.jdbc.pool.JdbcInterceptor; //导入依赖的package包/类
/**
 * Helper method that finds interceptor instance in interceptor chain of a
 * proxied class.
 *
 * @param proxy
 *            Proxy class
 * @param clazz
 *            Interceptor class that we are looking for
 * @return Instance of <code>clazz</code>
 */
private static <T extends JdbcInterceptor> T findInterceptor(Object proxy,
        Class<T> clazz) {
    JdbcInterceptor interceptor = (JdbcInterceptor) Proxy
            .getInvocationHandler(proxy);
    while (interceptor != null) {
        if (clazz.isInstance(interceptor)) {
            return clazz.cast(interceptor);
        }
        interceptor = interceptor.getNext();
    }
    return null;
}
 

import org.apache.tomcat.jdbc.pool.JdbcInterceptor; //导入依赖的package包/类
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    //get the name of the method for comparison
    final String name = method.getName();
    //was close invoked?
    boolean close = compare(JdbcInterceptor.CLOSE_VAL,name);
    //allow close to be called multiple times
    if (close && closed) return null;
    //are we calling isClosed?
    if (compare(JdbcInterceptor.ISCLOSED_VAL,name)) return Boolean.valueOf(closed);
    //if we are calling anything else, bail out
    if (closed) throw new SQLException("Statement closed.");
    //check to see if we are about to execute a query
    final boolean process = isExecute(method);
    Object result =  null;
    Subsegment subsegment = null;
    if (process) {
        subsegment = AWSXRay.beginSubsegment(hostname);
    }
    try {
        if (process && null != subsegment) {
            subsegment.putAllSql(additionalParams);
            subsegment.setNamespace(Namespace.REMOTE.toString());
        }
        result = method.invoke(delegate,args); //execute the query
    } catch (Throwable t) {
        if (null != subsegment) {
            subsegment.addException(t);
        }
        if (t instanceof InvocationTargetException && t.getCause() != null) {
            throw t.getCause();
        } else {
            throw t;
        }
    } finally {
        if (process && null != subsegment) {
            AWSXRay.endSubsegment();
        }
    }

    //perform close cleanup
    if (close) {
        closed = true;
        delegate = null;
    }

    return result;
}