core-it-support/core-it-plugins/maven-it-plugin-toolchain/src/main/java/org/apache/maven/plugin/coreit/CoreItMojo.java

package org.apache.maven.plugin.coreit;

/*
 * 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.execution.MavenSession;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.toolchain.ToolchainManagerPrivate;
import org.apache.maven.toolchain.ToolchainPrivate;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Properties;

/**
 * @goal toolchain
 * @phase validate
 */
public class CoreItMojo
    extends AbstractMojo
{

    /**
     * @component
     */
    private ToolchainManagerPrivate toolchainManager;

    /**
     * The current Maven session holding the selected toolchain.
     *
     * @parameter default-value="${session}"
     * @required
     * @readonly
     */
    private MavenSession session;

    /**
     * The path to the output file for the properties.
     *
     * @parameter property="toolchain.outputFile" default-value="${project.build.directory}/toolchains.properties"
     */
    private File outputFile;

    /**
     * The type identifier of the toolchain, e.g. "jdk".
     *
     * @parameter property="toolchain.type"
     */
    private String type;

    /**
     * The name of the tool, e.g. "javac".
     *
     * @parameter property="toolchain.tool"
     */
    private String tool;

    /**
     * The zero-based index of the toolchain to select and store in the build context.
     *
     * @parameter property="toolchain.selected"
     */
    private int selected;

    public void execute()
        throws MojoExecutionException
    {
        ToolchainPrivate[] tcs = getToolchains();

        getLog().info( "[MAVEN-CORE-IT-LOG] Toolchains in plugin: " + Arrays.asList( tcs ) );

        if ( selected >= 0 )
        {
            if ( selected < tcs.length )
            {
                ToolchainPrivate toolchain = tcs[selected];
                toolchainManager.storeToolchainToBuildContext( toolchain, session );
            }
            else
            {
                getLog().warn(
                    "[MAVEN-CORE-IT-LOG] Toolchain #" + selected + " can't be selected, found only " + tcs.length );
            }
        }

        Properties properties = new Properties();

        int count = 1;
        for ( Iterator<ToolchainPrivate> i = Arrays.asList( tcs ).iterator(); i.hasNext(); count++ )
        {
            ToolchainPrivate toolchain = i.next();

            String foundTool = toolchain.findTool( tool );
            if ( foundTool != null )
            {
                properties.setProperty( "tool." + count, foundTool );
            }
        }

        outputFile.getParentFile().mkdirs();
        try ( OutputStream out = new FileOutputStream( outputFile ) )
        {
            properties.store( out, "MAVEN-CORE-IT-LOG" );
        }
        catch ( IOException e )
        {
            throw new MojoExecutionException( e.getMessage(), e );
        }
    }

    private ToolchainPrivate[] getToolchains()
        throws MojoExecutionException
    {
        Class<? extends ToolchainManagerPrivate> managerClass = toolchainManager.getClass();

        try
        {
            try
            {
                // try 2.x style API
                Method oldMethod = managerClass.getMethod( "getToolchainsForType", new Class[]{ String.class } );

                return (ToolchainPrivate[]) oldMethod.invoke( toolchainManager, new Object[]{ type } );
            }
            catch ( NoSuchMethodException e )
            {
                // try 3.x style API
                Method newMethod =
                    managerClass.getMethod( "getToolchainsForType", new Class[]{ String.class, MavenSession.class } );

                return (ToolchainPrivate[]) newMethod.invoke( toolchainManager, new Object[]{ type, session } );
            }
        }
        catch ( NoSuchMethodException | InvocationTargetException | IllegalAccessException e )
        {
            throw new MojoExecutionException( "Incompatible toolchain API", e );
        }
    }

}