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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.log4j.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.spi.ErrorCode;
import org.apache.log4j.spi.LoggingEvent;
/**
The JDBCAppender provides for sending log events to a database.
WARNING: This version of JDBCAppender
is very likely to be completely replaced in the future. Moreoever,
it does not log exceptions.
Each append call adds to an ArrayList buffer. When
the buffer is filled each log event is placed in a sql statement
(configurable) and executed.
BufferSize, db URL, User, & Password are
configurable options in the standard log4j ways.
The setSql(String sql) sets the SQL statement to be
used for logging -- this statement is sent to a
PatternLayout (either created automaticly by the
appender or added by the user). Therefore by default all the
conversion patterns in PatternLayout can be used
inside of the statement. (see the test cases for examples)
Overriding the {@link #getLogStatement} method allows more
explicit control of the statement used for logging.
For use as a base class:
- Override
getConnection() to pass any connection
you want. Typically this is used to enable application wide
connection pooling.
- Override
closeConnection(Connection con) -- if
you override getConnection make sure to implement
closeConnection to handle the connection you
generated. Typically this would return the connection to the
pool it came from.
- Override
getLogStatement(LoggingEvent event) to
produce specialized or dynamic statements. The default uses the
sql option value.
@author Kevin Steppe ([email protected])
*/
public class JDBCAppender extends org.apache.log4j.AppenderSkeleton
implements org.apache.log4j.Appender {
/**
* URL of the DB for default connection handling
*/
protected String databaseURL = "jdbc:odbc:myDB";
/**
* User to connect as for default connection handling
*/
protected String databaseUser = "me";
/**
* User to use for default connection handling
*/
protected String databasePassword = "mypassword";
/**
* Connection used by default. The connection is opened the first time it
* is needed and then held open until the appender is closed (usually at
* garbage collection). This behavior is best modified by creating a
* sub-class and overriding the getConnection and
* closeConnection methods.
*/
protected Connection connection = null;
/**
* Stores the string given to the pattern layout for conversion into a SQL
* statement, eg: insert into LogTable (Thread, Class, Message) values
* ("%t", "%c", "%m").
*
* Be careful of quotes in your messages!
*
* Also see PatternLayout.
*/
protected String sqlStatement = "";
/**
* size of LoggingEvent buffer before writting to the database.
* Default is 1.
*/
protected int bufferSize = 1;
/**
* ArrayList holding the buffer of Logging Events.
*/
protected ArrayList buffer;
/**
* Helper object for clearing out the buffer
*/
protected ArrayList removes;
private boolean locationInfo = false;
public JDBCAppender() {
super();
buffer = new ArrayList(bufferSize);
removes = new ArrayList(bufferSize);
}
/**
* Gets whether the location of the logging request call
* should be captured.
*
* @since 1.2.16
* @return the current value of the LocationInfo option.
*/
public boolean getLocationInfo() {
return locationInfo;
}
/**
* The LocationInfo option takes a boolean value. By default, it is
* set to false which means there will be no effort to extract the location
* information related to the event. As a result, the event that will be
* ultimately logged will likely to contain the wrong location information
* (if present in the log format).
*
*
* Location information extraction is comparatively very slow and should be
* avoided unless performance is not a concern.
*
* @since 1.2.16
* @param flag true if location information should be extracted.
*/
public void setLocationInfo(final boolean flag) {
locationInfo = flag;
}
/**
* Adds the event to the buffer. When full the buffer is flushed.
*/
public void append(LoggingEvent event) {
event.getNDC();
event.getThreadName();
// Get a copy of this thread's MDC.
event.getMDCCopy();
if (locationInfo) {
event.getLocationInformation();
}
event.getRenderedMessage();
event.getThrowableStrRep();
buffer.add(event);
if (buffer.size() >= bufferSize)
flushBuffer();
}
/**
* By default getLogStatement sends the event to the required Layout object.
* The layout will format the given pattern into a workable SQL string.
*
* Overriding this provides direct access to the LoggingEvent
* when constructing the logging statement.
*
*/
protected String getLogStatement(LoggingEvent event) {
return getLayout().format(event);
}
/**
*
* Override this to provide an alertnate method of getting
* connections (such as caching). One method to fix this is to open
* connections at the start of flushBuffer() and close them at the
* end. I use a connection pool outside of JDBCAppender which is
* accessed in an override of this method.
* */
protected void execute(String sql) throws SQLException {
Connection con = null;
Statement stmt = null;
try {
con = getConnection();
stmt = con.createStatement();
stmt.executeUpdate(sql);
} finally {
if(stmt != null) {
stmt.close();
}
closeConnection(con);
}
//System.out.println("Execute: " + sql);
}
/**
* Override this to return the connection to a pool, or to clean up the
* resource.
*
* The default behavior holds a single connection open until the appender
* is closed (typically when garbage collected).
*/
protected void closeConnection(Connection con) {
}
/**
* Override this to link with your connection pooling system.
*
* By default this creates a single connection which is held open
* until the object is garbage collected.
*/
protected Connection getConnection() throws SQLException {
if (!DriverManager.getDrivers().hasMoreElements())
setDriver("sun.jdbc.odbc.JdbcOdbcDriver");
if (connection == null) {
connection = DriverManager.getConnection(databaseURL, databaseUser,
databasePassword);
}
return connection;
}
/**
* Closes the appender, flushing the buffer first then closing the default
* connection if it is open.
*/
public void close()
{
flushBuffer();
try {
if (connection != null && !connection.isClosed())
connection.close();
} catch (SQLException e) {
errorHandler.error("Error closing connection", e, ErrorCode.GENERIC_FAILURE);
}
this.closed = true;
}
/**
* loops through the buffer of LoggingEvents, gets a
* sql string from getLogStatement() and sends it to execute().
* Errors are sent to the errorHandler.
*
* If a statement fails the LoggingEvent stays in the buffer!
*/
public void flushBuffer() {
//Do the actual logging
removes.ensureCapacity(buffer.size());
for (Iterator i = buffer.iterator(); i.hasNext();) {
LoggingEvent logEvent = (LoggingEvent)i.next();
try {
String sql = getLogStatement(logEvent);
execute(sql);
}
catch (SQLException e) {
errorHandler.error("Failed to excute sql", e,
ErrorCode.FLUSH_FAILURE);
} finally {
removes.add(logEvent);
}
}
// remove from the buffer any events that were reported
buffer.removeAll(removes);
// clear the buffer of reported events
removes.clear();
}
/** closes the appender before disposal */
public void finalize() {
close();
}
/**
* JDBCAppender requires a layout.
* */
public boolean requiresLayout() {
return true;
}
/**
*
*/
public void setSql(String s) {
sqlStatement = s;
if (getLayout() == null) {
this.setLayout(new PatternLayout(s));
}
else {
((PatternLayout)getLayout()).setConversionPattern(s);
}
}
/**
* Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")
*/
public String getSql() {
return sqlStatement;
}
public void setUser(String user) {
databaseUser = user;
}
public void setURL(String url) {
databaseURL = url;
}
public void setPassword(String password) {
databasePassword = password;
}
public void setBufferSize(int newBufferSize) {
bufferSize = newBufferSize;
buffer.ensureCapacity(bufferSize);
removes.ensureCapacity(bufferSize);
}
public String getUser() {
return databaseUser;
}
public String getURL() {
return databaseURL;
}
public String getPassword() {
return databasePassword;
}
public int getBufferSize() {
return bufferSize;
}
/**
* Ensures that the given driver class has been loaded for sql connection
* creation.
*/
public void setDriver(String driverClass) {
try {
Class.forName(driverClass);
} catch (Exception e) {
errorHandler.error("Failed to load driver", e,
ErrorCode.GENERIC_FAILURE);
}
}
}
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