maven-plugin-testing-harness/src/main/java/org/apache/maven/plugin/testing/AbstractMojoTestCase.java

package org.apache.maven.plugin.testing;

/*
 * 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.
 */

import org.apache.maven.monitor.logging.DefaultLog;
import org.apache.maven.plugin.Mojo;
import org.apache.maven.plugin.logging.Log;
import org.codehaus.plexus.PlexusTestCase;
import org.codehaus.plexus.component.configurator.ComponentConfigurator;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
import org.codehaus.plexus.configuration.PlexusConfiguration;
import org.codehaus.plexus.configuration.xml.XmlPlexusConfiguration;
import org.codehaus.plexus.util.ReaderFactory;
import org.codehaus.plexus.util.ReflectionUtils;
import org.codehaus.plexus.util.xml.Xpp3Dom;
import org.codehaus.plexus.util.xml.Xpp3DomBuilder;

import java.io.File;
import java.io.Reader;
import java.util.Map;
import java.util.HashMap;
import java.lang.reflect.Field;
import java.lang.reflect.AccessibleObject;

/**
 * TODO: add a way to use the plugin POM for the lookup so that the user doesn't have to provide the a:g:v:goal
 * as the role hint for the mojo lookup.
 * TODO: standardize the execution of the mojo and looking at the results, but could simply have a template method
 * for verifying the state of the mojo post execution
 * TODO: need a way to look at the state of the mojo without adding getters, this could be where we finally specify
 * the expressions which extract values from the mojo.
 * TODO: create a standard directory structure for picking up POMs to make this even easier, we really just need a testing
 * descriptor and make this entirely declarative!
 *
 * @author jesse
 * @version $Id$
 */
public abstract class AbstractMojoTestCase
    extends PlexusTestCase
{
    private ComponentConfigurator configurator;

    /*
     * for the harness I think we have decided against going the route of using the maven project builder.
     * instead I think we are going to try and make an instance of the localrespository and assign that
     * to either the project stub or into the mojo directly with injection...not sure yet though.
     */
    //private MavenProjectBuilder projectBuilder;
    protected void setUp()
        throws Exception
    {
        super.setUp();

        configurator = (ComponentConfigurator) getContainer().lookup( ComponentConfigurator.ROLE, "basic" );

        //projectBuilder = (MavenProjectBuilder) getContainer().lookup( MavenProjectBuilder.ROLE );
    }

    /**
     * Lookup the mojo leveraging the subproject pom
     *
     * @param goal
     * @param pluginPom
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo lookupMojo( String goal, String pluginPom )
        throws Exception
    {
        return lookupMojo( goal, new File( pluginPom ) );
    }

    /**
     * Lookup an empty mojo
     *
     * @param goal
     * @param pluginPom
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo lookupEmptyMojo( String goal, String pluginPom )
        throws Exception
    {
        return lookupEmptyMojo( goal, new File( pluginPom ) );
    }

    /**
     * Lookup the mojo leveraging the actual subprojects pom
     *
     * @param goal
     * @param pom
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo lookupMojo( String goal, File pom )
        throws Exception
    {
        File pluginPom = new File( getBasedir(), "pom.xml" );

        Xpp3Dom pluginPomDom = Xpp3DomBuilder.build( ReaderFactory.newXmlReader( pluginPom ) );

        String artifactId = pluginPomDom.getChild( "artifactId" ).getValue();

        String groupId = resolveFromRootThenParent( pluginPomDom, "groupId" );

        String version = resolveFromRootThenParent( pluginPomDom, "version" );

        PlexusConfiguration pluginConfiguration = extractPluginConfiguration( artifactId, pom );

        return lookupMojo( groupId, artifactId, version, goal, pluginConfiguration );
    }

    /**
     * Lookup the mojo leveraging the actual subprojects pom
     *
     * @param goal
     * @param pom
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo lookupEmptyMojo( String goal, File pom )
        throws Exception
    {
        File pluginPom = new File( getBasedir(), "pom.xml" );

        Xpp3Dom pluginPomDom = Xpp3DomBuilder.build( ReaderFactory.newXmlReader( pluginPom ) );

        String artifactId = pluginPomDom.getChild( "artifactId" ).getValue();

        String groupId = resolveFromRootThenParent( pluginPomDom, "groupId" );

        String version = resolveFromRootThenParent( pluginPomDom, "version" );

        return lookupMojo( groupId, artifactId, version, goal, null );
    }

    /*
     protected Mojo lookupMojo( String groupId, String artifactId, String version, String goal, File pom )
     throws Exception
     {
     PlexusConfiguration pluginConfiguration = extractPluginConfiguration( artifactId, pom );

     return lookupMojo( groupId, artifactId, version, goal, pluginConfiguration );
     }
     */
    /**
     * lookup the mojo while we have all of the relavent information
     *
     * @param groupId
     * @param artifactId
     * @param version
     * @param goal
     * @param pluginConfiguration
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo lookupMojo( String groupId, String artifactId, String version, String goal,
                               PlexusConfiguration pluginConfiguration )
        throws Exception
    {
        validateContainerStatus();

        // pluginkey = groupId : artifactId : version : goal

        Mojo mojo = (Mojo) lookup( Mojo.ROLE, groupId + ":" + artifactId + ":" + version + ":" + goal );

        Log mojoLogger = new DefaultLog( container.getLoggerManager().getLoggerForComponent( Mojo.ROLE ) );

        mojo.setLog( mojoLogger );

        if ( pluginConfiguration != null )
        {
            /* requires v10 of plexus container for lookup on expression evaluator
             ExpressionEvaluator evaluator = (ExpressionEvaluator) getContainer().lookup( ExpressionEvaluator.ROLE,
                                                                                         "stub-evaluator" );
             */
            ExpressionEvaluator evaluator = new ResolverExpressionEvaluatorStub();

            configurator.configureComponent( mojo, pluginConfiguration, evaluator, getContainer().getContainerRealm() );
        }

        return mojo;
    }

    /**
     * @param artifactId
     * @param pom
     * @return the plexus configuration
     * @throws Exception
     */
    protected PlexusConfiguration extractPluginConfiguration( String artifactId, File pom )
        throws Exception
    {
        Reader reader = ReaderFactory.newXmlReader( pom );

        Xpp3Dom pomDom = Xpp3DomBuilder.build( reader );

        return extractPluginConfiguration( artifactId, pomDom );
    }

    /**
     * @param artifactId
     * @param pomDom
     * @return the plexus configuration
     * @throws Exception
     */
    protected PlexusConfiguration extractPluginConfiguration( String artifactId, Xpp3Dom pomDom )
        throws Exception
    {
        Xpp3Dom pluginConfigurationElement = null;

        Xpp3Dom buildElement = pomDom.getChild( "build" );
        if ( buildElement != null )
        {
            Xpp3Dom pluginsRootElement = buildElement.getChild( "plugins" );

            if ( pluginsRootElement != null )
            {
                Xpp3Dom[] pluginElements = pluginsRootElement.getChildren();

                for ( int i = 0; i < pluginElements.length; i++ )
                {
                    Xpp3Dom pluginElement = pluginElements[i];

                    String pluginElementArtifactId = pluginElement.getChild( "artifactId" ).getValue();

                    if ( pluginElementArtifactId.equals( artifactId ) )
                    {
                        pluginConfigurationElement = pluginElement.getChild( "configuration" );

                        break;
                    }
                }

                if ( pluginConfigurationElement == null )
                {
                    throw new ConfigurationException( "Cannot find a configuration element for a plugin with an artifactId of " + artifactId + "." );
                }
            }
        }

        if ( pluginConfigurationElement == null )
        {
            throw new ConfigurationException( "Cannot find a configuration element for a plugin with an artifactId of "
                + artifactId + "." );
        }

        return new XmlPlexusConfiguration( pluginConfigurationElement );
    }

    /**
     * Configure the mojo
     *
     * @param mojo
     * @param artifactId
     * @param pom
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo configureMojo( Mojo mojo, String artifactId, File pom )
        throws Exception
    {
        validateContainerStatus();

        PlexusConfiguration pluginConfiguration = extractPluginConfiguration( artifactId, pom );

        ExpressionEvaluator evaluator = new ResolverExpressionEvaluatorStub();

        configurator.configureComponent( mojo, pluginConfiguration, evaluator, getContainer().getContainerRealm() );

        return mojo;
    }

    /**
     * Configure the mojo with the given plexus configuration
     *
     * @param mojo
     * @param pluginConfiguration
     * @return a Mojo instance
     * @throws Exception
     */
    protected Mojo configureMojo( Mojo mojo, PlexusConfiguration pluginConfiguration )
        throws Exception
    {
        validateContainerStatus();

        ExpressionEvaluator evaluator = new ResolverExpressionEvaluatorStub();

        configurator.configureComponent( mojo, pluginConfiguration, evaluator, getContainer().getContainerRealm() );

        return mojo;
    }

    /**
     * Convenience method to obtain the value of a variable on a mojo that might not have a getter.
     *
     * NOTE: the caller is responsible for casting to to what the desired type is.
     *
     * @param object
     * @param variable
     * @return object value of variable
     * @throws IllegalArgumentException
     */
    protected Object getVariableValueFromObject( Object object, String variable )
        throws IllegalAccessException
    {
        Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses( variable, object.getClass() );

        field.setAccessible( true );

        return field.get( object );
    }

    /**
     * Convenience method to obtain all variables and values from the mojo (including its superclasses)
     *
     * Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
     *
     * @param object
     * @return map of variable names and values
     */
    protected Map getVariablesAndValuesFromObject( Object object )
        throws IllegalAccessException
    {
        return getVariablesAndValuesFromObject( object.getClass(), object );
    }

    /**
     * Convenience method to obtain all variables and values from the mojo (including its superclasses)
     *
     * Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
     *
     * @param clazz
     * @param object
     * @return map of variable names and values
     */
    protected Map getVariablesAndValuesFromObject( Class clazz, Object object )
        throws IllegalAccessException
    {
        Map map = new HashMap();

        Field[] fields = clazz.getDeclaredFields();

        AccessibleObject.setAccessible( fields, true );

        for ( int i = 0; i < fields.length; ++i )
        {
            Field field = fields[i];

            map.put( field.getName(), field.get( object ) );

        }

        Class superclass = clazz.getSuperclass();

        if ( !Object.class.equals( superclass ) )
        {
            map.putAll( getVariablesAndValuesFromObject( superclass, object ) );
        }

        return map;
    }

    /**
     * Convenience method to set values to variables in objects that don't have setters
     *
     * @param object
     * @param variable
     * @param value
     * @throws IllegalAccessException
     */
    protected void setVariableValueToObject( Object object, String variable, Object value )
        throws IllegalAccessException
    {
        Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses( variable, object.getClass() );

        field.setAccessible( true );

        field.set( object, value );
    }

    /**
     * sometimes the parent element might contain the correct value so generalize that access
     *
     * TODO find out where this is probably done elsewhere
     *
     * @param pluginPomDom
     * @param element
     * @return
     * @throws Exception
     */
    private String resolveFromRootThenParent( Xpp3Dom pluginPomDom, String element )
        throws Exception
    {
        Xpp3Dom elementDom = pluginPomDom.getChild( element );

        // parent might have the group Id so resolve it
        if ( elementDom == null )
        {
            Xpp3Dom pluginParentDom = pluginPomDom.getChild( "parent" );

            if ( pluginParentDom != null )
            {
                elementDom = pluginParentDom.getChild( element );

                if ( elementDom == null )
                {
                    throw new Exception( "unable to determine " + element );
                }

                return elementDom.getValue();
            }

            throw new Exception( "unable to determine " + element );
        }

        return elementDom.getValue();
    }

    /**
     * We should make sure this is called in each method that makes use of the container,
     * otherwise we throw ugly NPE's
     *
     * crops up when the subclassing code defines the setUp method but doesn't call super.setUp()
     *
     * @throws Exception
     */
    private void validateContainerStatus()
        throws Exception
    {
        if ( container != null )
        {
            return;
        }

        throw new Exception( "container is null, make sure super.setUp() is called" );
    }
}