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/*
 * Copyright 2019 IIT Software GmbH
 *
 * IIT Software GmbH 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.swiftmq.swiftlet;

import com.swiftmq.mgmt.Configuration;

/**
 * Swiftlets are components of a SwiftMQ router and are under control of the SwiftletManager.
 * 


 * Implementing classes overwrite the startup and shutdown method.
 * 


 * A Swiftlet is instantiated from the SwiftletManager. All Kernel Swiftlets are sharing one
 * class loader, and every Extension Swiftlet has his own class loader.
 *
 * @author IIT GmbH, Bremen/Germany, Copyright (c) 2000-2002, All Rights Reserved
 * @see SwiftletManager
 */
public abstract class Swiftlet {
    public final static int STATE_ACTIVE = 0;
    public final static int STATE_INACTIVE = 1;
    public final static int STATE_STANDBY = 2;

    String name;
    int state = STATE_INACTIVE;
    long startupTime;
    boolean kernel = false;
    Configuration __myconf = null;

    /**
     * Returns the name of the Swiftlet
     *
     * @return swiftlet name
     */
    public String getName() {
        return (name);
    }

    void setName(String name) {
        this.name = name;
    }

    /**
     * Returns the current swiftlet state
     *
     * @return current state
     */
    public int getState() {
        return state;
    }

    /**
     * Set a new swiftlet state
     */
    void setState(int state) {
        this.state = state;
    }

    boolean isKernel() {
        return kernel;
    }

    void setKernel(boolean b) {
        this.kernel = b;
    }

    /**
     * Returns the Swiftlet startup time
     *
     * @return startup time.
     */
    public long getStartupTime() {
        return (startupTime);
    }

    /**
     * Set the startup time.
     * Called from the SwiftletManager.
     *
     * @param startupTime startup time.
     */
    protected void setStartupTime(long startupTime) {
        this.startupTime = startupTime;
    }

    /**
     * Returns whether this Swiftlet provides Snapshots
     *
     * @return snapshot available.
     */
    public boolean isSnapshotAvailable() {
        return false;
    }

    /**
     * Start this Swiftlet.
     * Called from the SwiftletManager during router start. The Swiftlet configuration is
     * passed as parameter.
     *
     * @param config Swiftlet configuration.
     * @throws SwiftletException on error during startup.
     */
    protected abstract void startup(Configuration config) throws SwiftletException;

    /**
     * Start this Swiftlet in standby mode. This method must be implemented from
     * Kernel Swiftlets only.
     *
     * @param config Swiftlet configuration.
     * @throws SwiftletException on error during startup.
     */
    protected void standby(Configuration config) throws SwiftletException {
        __myconf = config;
    }

    /**
     * Resume this Swiftlet after it has been in standby mode. The Swiftlet changes to active.
     * This method must be implemented from Kernel Swiftlets only.
     *
     * @throws SwiftletException on error during startup.
     */
    protected void resume() throws SwiftletException {
        startup(__myconf);
    }


    /**
     * Stop this Swiftlet.
     * Called from the SwiftletManager during router shutdown.
     *
     * @throws SwiftletException on error during shutdown.
     * @see package.class
     */
    protected abstract void shutdown() throws SwiftletException;
}