core-it-support/core-it-plugins/maven-it-plugin-toolchain/src/main/java/org/apache/maven/plugin/coreit/FindToolMojo.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 java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Properties;

import org.apache.maven.execution.MavenSession;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.toolchain.Toolchain;
import org.apache.maven.toolchain.ToolchainManager;

/**
 * Finds a tool from a previously selected toolchain. This tests the public API just like toolchain-enabled plugins
 * would do.
 * 
 * @goal find-tool
 * @phase validate
 */
public class FindToolMojo
    extends AbstractMojo
{

    /**
     * @component
     */
    private ToolchainManager 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}/tool.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;

    public void execute()
        throws MojoExecutionException
    {
        Toolchain toolchain = toolchainManager.getToolchainFromBuildContext( type, session );

        getLog().info( "[MAVEN-CORE-IT-LOG] Toolchain in session: " + toolchain );

        Properties properties = new Properties();

        if ( toolchain != null )
        {
            properties.setProperty( "toolchain.type", toolchain.getType() );

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

        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 );
        }
    }
}