001    package org.apache.maven.eventspy;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    import java.util.Map;
023    
024    /**
025     * A core extension to monitor Maven's execution. Typically, such an extension gets loaded into Maven by specifying the
026     * system property {@code maven.ext.class.path} on the command line. As soon as dependency injection is setup, Maven
027     * looks up all implementators of this interface and calls their {@link #init(Context)} method. <em>Note:</em>
028     * Implementors are strongly advised to inherit from {@link AbstractEventSpy} instead of directly implementing this
029     * interface.
030     */
031    public interface EventSpy
032    {
033    
034        interface Context
035        {
036    
037            /**
038             * Gets key-value pairs providing information about the Maven runtime.
039             * 
040             * @return The key-value pairs, never {@code null}.
041             */
042            Map<String, Object> getData();
043    
044        }
045    
046        /**
047         * Initializes the spy.
048         * 
049         * @param context The event spy context, never {@code null}.
050         */
051        void init( Context context )
052            throws Exception;
053    
054        /**
055         * Notifies the spy of some build event/operation.
056         * 
057         * @param event The event, never {@@code null}.
058         * @see org.apache.maven.settings.building.SettingsBuildingRequest
059         * @see org.apache.maven.settings.building.SettingsBuildingResult
060         * @see org.apache.maven.execution.MavenExecutionRequest
061         * @see org.apache.maven.execution.MavenExecutionResult
062         * @see org.apache.maven.project.DependencyResolutionRequest
063         * @see org.apache.maven.project.DependencyResolutionResultt
064         * @see org.apache.maven.execution.ExecutionEvent
065         * @see org.sonatype.aether.RepositoryEvent
066         */
067        void onEvent( Object event )
068            throws Exception;
069    
070        /**
071         * Notifies the spy of Maven's termination, allowing it to free any resources allocated by it.
072         */
073        void close()
074            throws Exception;
075    
076    }