com.iflytek.spider.util.LogUtil.java Source code

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Here is the source code for com.iflytek.spider.util.LogUtil.java

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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 com.iflytek.spider.util;

// JDK imports
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.lang.reflect.Method;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
// Commons Logging imports

/**
 * Utility class for logging.
 *
 * @author Jérôme Charron
 */
public class LogUtil {

    private final static Log LOG = LogFactory.getLog(LogUtil.class);

    private static Method TRACE = null;
    private static Method DEBUG = null;
    private static Method INFO = null;
    private static Method WARN = null;
    private static Method ERROR = null;
    private static Method FATAL = null;

    static {
        try {
            TRACE = Log.class.getMethod("trace", new Class[] { Object.class });
            DEBUG = Log.class.getMethod("debug", new Class[] { Object.class });
            INFO = Log.class.getMethod("info", new Class[] { Object.class });
            WARN = Log.class.getMethod("warn", new Class[] { Object.class });
            ERROR = Log.class.getMethod("error", new Class[] { Object.class });
            FATAL = Log.class.getMethod("fatal", new Class[] { Object.class });
        } catch (Exception e) {
            if (LOG.isErrorEnabled()) {
                LOG.error("Cannot init log methods", e);
            }
        }
    }

    public static PrintStream getTraceStream(final Log logger) {
        return getLogStream(logger, TRACE);
    }

    public static PrintStream getDebugStream(final Log logger) {
        return getLogStream(logger, DEBUG);
    }

    public static PrintStream getInfoStream(final Log logger) {
        return getLogStream(logger, INFO);
    }

    public static PrintStream getWarnStream(final Log logger) {
        return getLogStream(logger, WARN);
    }

    public static PrintStream getErrorStream(final Log logger) {
        return getLogStream(logger, ERROR);
    }

    public static PrintStream getFatalStream(final Log logger) {
        return getLogStream(logger, FATAL);
    }

    /** Returns a stream that, when written to, adds log lines. */
    private static PrintStream getLogStream(final Log logger, final Method method) {
        return new PrintStream(new ByteArrayOutputStream() {
            private int scan = 0;

            private boolean hasNewline() {
                for (; scan < count; scan++) {
                    if (buf[scan] == '\n')
                        return true;
                }
                return false;
            }

            public void flush() throws IOException {
                if (!hasNewline())
                    return;
                try {
                    method.invoke(logger, new Object[] { toString().trim() });
                } catch (Exception e) {
                    if (LOG.isFatalEnabled()) {
                        LOG.fatal("Cannot log with method [" + method + "]", e);
                    }
                }
                reset();
                scan = 0;
            }
        }, true);
    }

}