java/org/apache/catalina/Engine.java

/*
 * 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 org.apache.catalina;

/**
 * An <b>Engine</b> is a Container that represents the entire Catalina servlet engine. It is useful in the following
 * types of scenarios:
 * <ul>
 * <li>You wish to use Interceptors that see every single request processed by the entire engine.
 * <li>You wish to run Catalina in with a standalone HTTP connector, but still want support for multiple virtual hosts.
 * </ul>
 * In general, you would not use an Engine when deploying Catalina connected to a web server (such as Apache), because
 * the Connector will have utilized the web server's facilities to determine which Context (or perhaps even which
 * Wrapper) should be utilized to process this request.
 * <p>
 * The child containers attached to an Engine are generally implementations of Host (representing a virtual host) or
 * Context (representing individual an individual servlet context), depending upon the Engine implementation.
 * <p>
 * If used, an Engine is always the top level Container in a Catalina hierarchy. Therefore, the implementation's
 * <code>setParent()</code> method should throw <code>IllegalArgumentException</code>.
 */
public interface Engine extends Container {

    /**
     * @return the default host name for this Engine.
     */
    String getDefaultHost();


    /**
     * Set the default hostname for this Engine.
     *
     * @param defaultHost The new default host
     */
    void setDefaultHost(String defaultHost);


    /**
     * @return the JvmRouteId for this engine.
     */
    String getJvmRoute();


    /**
     * Set the JvmRouteId for this engine.
     *
     * @param jvmRouteId the (new) JVM Route ID. Each Engine within a cluster must have a unique JVM Route ID.
     */
    void setJvmRoute(String jvmRouteId);


    /**
     * @return the <code>Service</code> with which we are associated (if any).
     */
    Service getService();


    /**
     * Set the <code>Service</code> with which we are associated (if any).
     *
     * @param service The service that owns this Engine
     */
    void setService(Service service);
}