com.github.htfv.maven.plugins.testing.internal.MavenTestClassLoader Maven / Gradle / Ivy

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package com.github.htfv.maven.plugins.testing.internal;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

/**
 * {@link ClassLoader} implementation which hides resources from the workspace
 * artifacts. This is mainly required to remove
 * {@code META-INF/plexus/components.xml} from the system and core class
 * loaders. If it is not done, the extensions may be executed twice: first from
 * the core class loader, then from the plugin class loader.
 *
 * @author htfv (Aliaksei Lahachou)
 */
public class MavenTestClassLoader extends ClassLoader
{
    /**
     * Build a list of URLs under which all resources are hidden.
     *
     * @return The list of URLs.
     */
    private static List getHiddenResourceURIs()
    {
        List hiddenResourceURIs = new ArrayList();

        hiddenResourceURIs.add(new File("").toURI().toString());

        return hiddenResourceURIs;
    }

    /**
     * The list of URLs under which all resources are hidden.
     */
    private final List hiddenResourceURIs;

    /**
     * Constructs a new instance of {@link MavenTestClassLoader}.
     *
     * @param parentClassLoader
     *            the parent {@link ClassLoader}.
     */
    public MavenTestClassLoader(final ClassLoader parentClassLoader)
    {
        super(parentClassLoader);

        //
        // Build the list of URLs now, because later it may cause recursive
        // class loading.
        //

        this.hiddenResourceURIs = getHiddenResourceURIs();
    }

    @Override
    public Enumeration getResources(final String name) throws IOException
    {
        Enumeration resources = super.getResources(name);

        resources = new AbstractFilteredEnumeration(resources)
        {
            @Override
            protected boolean shouldIncludeElement(final URL element)
            {
                for (String hiddenResourceURI : hiddenResourceURIs)
                {
                    if (element.toString().startsWith(hiddenResourceURI))
                    {
                        return false;
                    }
                }

                return true;
            }
        };

        return resources;
    }
}