private void shallowMerge(
            List<ToolchainModel> dominant, List<ToolchainModel> recessive, String recessiveSourceLevel) {
        Map<Object, ToolchainModel> merged = new LinkedHashMap<>();

        for (ToolchainModel dominantModel : dominant) {
            Object key = getToolchainModelKey(dominantModel);

            merged.put(key, dominantModel);
        }

        for (ToolchainModel recessiveModel : recessive) {

            }
        };
    }

    @Test
    void testGetModel() {
        ToolchainModel model = new ToolchainModel();
        DefaultToolchain toolchain = newDefaultToolchain(model);
        assertEquals(model, toolchain.getModel());
    }

    @Test
    void testGetType() {
        ToolchainModel model = new ToolchainModel();
        DefaultToolchain toolchain = newDefaultToolchain(model, "TYPE");

import org.apache.maven.api.Toolchain;
import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.toolchain.ToolchainModel;

/**
 * Factory interface for creating toolchain instances from configuration models.
 *
 * <p>This factory is responsible for instantiating concrete toolchain implementations

    public static final String KEY_TYPE = "type"; // NOI18N

    private ToolchainModel model;

    /**
     *
     * @param model the model, must not be {@code null}
     * @param logger the logger, must not be {@code null}
     */
    protected DefaultToolchain(ToolchainModel model, Logger logger) {
        this.model = model;
        this.logger = logger;
    }

    /**
     *

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.toolchain.java;

import org.apache.maven.toolchain.model.ToolchainModel;
import org.slf4j.Logger;

/**
 * Provides backwards compatibility with Maven 3.2.3 and earlier. Clients that do not require compatibility with Maven
 * 3.2.3 and earlier are encouraged to use {@link JavaToolchainImpl}.

    }

    @Nonnull
    @Override
    public Collection<ToolchainModel> getToolchains() {
        return getMavenSession().getRequest().getToolchains().values().stream()
                .flatMap(Collection::stream)
                .map(org.apache.maven.toolchain.model.ToolchainModel::getDelegate)
                .toList();
    }

    @Nonnull
    @Override

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.toolchain;

import org.apache.maven.toolchain.model.ToolchainModel;

/**
 * Internal toolchain factory, to prepare toolchains instances.
 *
 * @since 2.0.9
 * @deprecated Use {@link org.apache.maven.api.services.ToolchainFactory} instead.
 */
@Deprecated(since = "4.0.0")

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.toolchain;

import java.util.Map;

import org.apache.maven.toolchain.model.ToolchainModel;

/**
 * a private contract between the toolchains plugin and the components.
 *
 * @deprecated Use {@link org.apache.maven.api.Toolchain} instead.
 */
@Deprecated(since = "4.0.0")

import org.apache.maven.toolchain.RequirementMatcherFactory;
import org.apache.maven.toolchain.ToolchainFactory;
import org.apache.maven.toolchain.ToolchainPrivate;
import org.apache.maven.toolchain.model.ToolchainModel;
import org.codehaus.plexus.util.xml.Xpp3Dom;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * JDK toolchain factory.
 * This is a <code>ToolchainFactory</code> Plexus component registered with

            throws MavenExecutionRequestPopulationException {
        if (toolchains != null) {
            Map<String, List<ToolchainModel>> groupedToolchains = new HashMap<>(2);

            for (ToolchainModel model : toolchains.getToolchains()) {
                if (!groupedToolchains.containsKey(model.getType())) {
                    groupedToolchains.put(model.getType(), new ArrayList<>());