LogConfig.java

// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed 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.eclipse.che.ide.util.loging;

import com.google.gwt.user.client.Window;

/**
 * Deferred bound class to determing statically whether or not logging is
 * enabled.
 * <p/>
 * This is package protected all the way and only used internally by
 * {@link Log}.
 */
class LogConfig {
    public static enum LogLevel {
        DEBUG, INFO, WARNING, ERROR
    }

    private static final String LOG_LEVEL_PARAM = "logLevel";

    private static final LogConfig INSTANCE = new LogConfig();

    static LogLevel getLogLevel() {
        return INSTANCE.getLogLevelImpl();
    }

    static void setLogLevel(LogLevel level) {
        INSTANCE.setLogLevelImpl(level);
    }

    private LogLevel currentLevel = null;

    private void ensureLogLevel() {
        if (currentLevel == null) {
            // First inspect the URL to see if it has one set.
            setLogLevel(maybeGetLevelFromUrl());

            // If it is still not set, make the default be INFO.
            setLogLevel((currentLevel == null) ? LogLevel.INFO : currentLevel);
        }
    }

    private LogLevel getLogLevelImpl() {
        ensureLogLevel();
        return currentLevel;
    }

    private LogLevel maybeGetLevelFromUrl() {
        String levelStr = Window.Location.getParameter(LOG_LEVEL_PARAM);

        // The common case.
        if (levelStr == null) {
            return null;
        }

        levelStr = levelStr.toUpperCase();

        try {
            // Extract the correct Enum value;
            return LogLevel.valueOf(levelStr);
        } catch (IllegalArgumentException e) {
            // We had a String but it was malformed.
            return null;
        }
    }

    private void setLogLevelImpl(LogLevel level) {
        currentLevel = level;
    }
}