package org.apache.velocity.runtime.log; /* * 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. */ import java.io.StringWriter; import java.io.PrintWriter; import javax.servlet.ServletContext; import org.apache.velocity.runtime.RuntimeServices; /** * Simple wrapper for the servlet log. This passes Velocity log * messages to ServletContext.log(String). You may configure the * level of output in your velocity.properties by adding the * "runtime.log.logsystem.servlet.level" property with one of the * following values: error, warn, info, debug, or trace. The default * is trace. * * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a> * @author Nathan Bubna * @version $Revision: 730039 $ $Date: 2008-12-30 04:53:19 +0100 (mar., 30 déc. 2008) $ * @since 1.6 */ public class ServletLogChute implements LogChute { public static final String RUNTIME_LOG_LEVEL_KEY = "runtime.log.logsystem.servlet.level"; private int enabled = TRACE_ID; protected ServletContext servletContext = null; public static final String PREFIX = " Velocity "; /** * Construct a simple logger for a servlet environment. * <br> * NOTE: this class expects that the ServletContext has already * been placed in the runtime's application attributes * under its full class name (i.e. "javax.servlet.ServletContext"). */ public ServletLogChute() { } /** * init() * * @throws IllegalStateException if the ServletContext is not available * in the application attributes under the appropriate key. */ public void init(RuntimeServices rs) throws Exception { Object obj = rs.getApplicationAttribute(ServletContext.class.getName()); if (obj == null) { throw new UnsupportedOperationException("Could not retrieve ServletContext from application attributes"); } servletContext = (ServletContext)obj; // look for a level config property String level = (String)rs.getProperty(RUNTIME_LOG_LEVEL_KEY); if (level != null) { // and set it accordingly setEnabledLevel(toLevel(level)); } } protected int toLevel(String level) { if (level.equalsIgnoreCase("debug")) { return DEBUG_ID; } else if (level.equalsIgnoreCase("info")) { return INFO_ID; } else if (level.equalsIgnoreCase("warn")) { return WARN_ID; } else if (level.equalsIgnoreCase("error")) { return ERROR_ID; } else { return TRACE_ID; } } /** * Set the minimum level at which messages will be printed. */ public void setEnabledLevel(int level) { this.enabled = level; } /** * Returns the current minimum level at which messages will be printed. */ public int getEnabledLevel() { return this.enabled; } /** * This will return true if the specified level * is equal to or higher than the level this * LogChute is enabled for. */ public boolean isLevelEnabled(int level) { return (level >= this.enabled); } /** * Send a log message from Velocity. */ public void log(int level, String message) { if (!isLevelEnabled(level)) { return; } switch (level) { case WARN_ID: servletContext.log(PREFIX + WARN_PREFIX + message); break; case INFO_ID: servletContext.log(PREFIX + INFO_PREFIX + message); break; case DEBUG_ID: servletContext.log(PREFIX + DEBUG_PREFIX + message); break; case TRACE_ID: servletContext.log(PREFIX + TRACE_PREFIX + message); break; case ERROR_ID: servletContext.log(PREFIX + ERROR_PREFIX + message); break; default: servletContext.log(PREFIX + " : " + message); break; } } public void log(int level, String message, Throwable t) { if (!isLevelEnabled(level)) { return; } message += " - "+t.toString(); if (level >= ERROR_ID) { StringWriter sw = new StringWriter(); t.printStackTrace(new PrintWriter(sw)); message += "\n" + sw.toString(); } log(level, message); } }