<?php
/**
 * 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.
 */

namespace Apache\Log4php;

use Apache\Log4php\Appenders\AbstractAppender;

/**
 * Pool implmentation for Appender instances.
 *
 * The pool is used when configuring log4php. First all appender instances
 * are created in the pool. Afterward, they are linked to loggers, each
 * appender can be linked to multiple loggers. This makes sure duplicate
 * appenders are not created.
 *
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 * @link http://logging.apache.org/log4php
 */
class AppenderPool
{
    /** Holds appenders indexed by their name */
    public static $appenders =  array();

    /**
     * Adds an appender to the pool.
     * The appender must be named for this operation.
     * @param AbstractAppender $appender
     */
    public static function add(AbstractAppender $appender)
    {
        $name = $appender->getName();

        if (empty($name)) {
            trigger_error('log4php: Cannot add unnamed appender to pool.', E_USER_WARNING);

            return;
        }

        if (isset(self::$appenders[$name])) {
            trigger_error(
                "log4php: Appender [$name] already exists in pool. Overwriting existing appender.",
                E_USER_WARNING
            );
        }

        self::$appenders[$name] = $appender;
    }

    /**
     * Retrieves an appender from the pool by name.
     * @param  string   $name Name of the appender to retrieve.
     * @return AbstractAppender The named appender or NULL if no such appender
     *  exists in the pool.
     */
    public static function get($name)
    {
        return isset(self::$appenders[$name]) ? self::$appenders[$name] : null;
    }

    /**
    * Removes an appender from the pool by name.
    * @param string $name Name of the appender to remove.
    */
    public static function delete($name)
    {
        unset(self::$appenders[$name]);
    }

    /**
     * Returns all appenders from the pool.
     * @return array Array of Appender objects.
     */
    public static function getAppenders()
    {
        return self::$appenders;
    }

    /**
     * Checks whether an appender exists in the pool.
     * @param  string  $name Name of the appender to look for.
     * @return boolean TRUE if the appender with the given name exists.
     */
    public static function exists($name)
    {
        return isset(self::$appenders[$name]);
    }

    /**
     * Clears all appenders from the pool.
     */
    public static function clear()
    {
         self::$appenders =  array();
    }
}