src/main/java/org/apache/maven/plugins/toolchain/ToolchainConverter.java

package org.apache.maven.plugins.toolchain;

/*
 * 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.util.AbstractMap;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;

import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
import org.codehaus.plexus.component.configurator.ConfigurationListener;
import org.codehaus.plexus.component.configurator.converters.AbstractConfigurationConverter;
import org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
import org.codehaus.plexus.configuration.PlexusConfiguration;

/**
 * Custom Plexus ConfigurationConverter to instantiate <code>ToolchainRequirement</code> from configuration.
 *
 * @author mkleint
 * @see ToolchainsRequirement
 */
public class ToolchainConverter
    extends AbstractConfigurationConverter
{

    /**
     * @see org.codehaus.plexus.component.configurator.converters.ConfigurationConverter#canConvert(java.lang.Class)
     */
    @Override
    public boolean canConvert( Class type )
    {
        return ToolchainsRequirement.class.isAssignableFrom( type );
    }

    /**
     * @see org.codehaus.plexus.component.configurator.converters.ConfigurationConverter#fromConfiguration(org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup, org.codehaus.plexus.configuration.PlexusConfiguration, java.lang.Class, java.lang.Class, java.lang.ClassLoader, org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator, org.codehaus.plexus.component.configurator.ConfigurationListener)
     */
    @Override
    public Object fromConfiguration( ConverterLookup converterLookup,
                                     PlexusConfiguration configuration,
                                     Class type, Class baseType,
                                     ClassLoader classLoader,
                                     ExpressionEvaluator expressionEvaluator,
                                     ConfigurationListener listener )
        throws ComponentConfigurationException
    {
        ToolchainsRequirement retValue = new ToolchainsRequirement();

        processConfiguration( retValue, configuration, expressionEvaluator );

        return retValue;
    }

    private void processConfiguration( ToolchainsRequirement requirement,
                                       PlexusConfiguration configuration,
                                       ExpressionEvaluator expressionEvaluator )
    {
        Map<String, Map<String, String>> map = new HashMap<>();

        PlexusConfiguration[] tools = configuration.getChildren();
        for ( PlexusConfiguration tool : tools )
        {
            String type = tool.getName();
            PlexusConfiguration[] params = tool.getChildren();

            Map<String, String> parameters =
                    Arrays.stream( params ).collect( Collectors.toMap( PlexusConfiguration::getName,
                            PlexusConfiguration::getValue ) );
            map.put( type, parameters );
        }

        Arrays.stream( configuration.getChildren() )
        .map( s ->
            new AbstractMap.SimpleEntry<>( s.getName(),
                    Arrays.stream( s.getChildren() ).collect( Collectors.toMap( PlexusConfiguration::getName,
                            PlexusConfiguration::getValue ) ) )

        ).collect( Collectors.toMap( k -> k, v -> v ) );
        requirement.toolchains = map;
    }
}