* result of a <i>future</i> call to {@code next()}.
   */
  protected abstract @Nullable T computeNext(T previous);

  @Override
  public final boolean hasNext() {
    return nextOrNull != null;
  }

  @Override
  public final T next() {
    if (nextOrNull == null) {
      throw new NoSuchElementException();
    }
    T oldNext = nextOrNull;
    nextOrNull = computeNext(oldNext);

 * @since 4.0
 */
@GwtCompatible
public abstract class ForwardingListenableFuture<V extends @Nullable Object>
    extends ForwardingFuture<V> implements ListenableFuture<V> {

  /** Constructor for use by subclasses. */
  protected ForwardingListenableFuture() {}

  @Override
  protected abstract ListenableFuture<? extends V> delegate();

  @Override
  public void addListener(Runnable listener, Executor exec) {

 * data like the plugin realm. <strong>Warning:</strong> This is an internal utility interface that is only public for
 * technical reasons, it is not part of the public API. In particular, this interface can be changed or deleted without
 * prior notice.
 *
 * @since 3.0
 */
public interface PluginDescriptorCache {

    /**
     * A cache key.
     */
    interface Key {

import org.eclipse.aether.version.VersionScheme;

@Named
@Singleton
public class MavenPluginJavaPrerequisiteChecker implements MavenPluginPrerequisitesChecker {
    private final VersionScheme versionScheme;

    @Inject
    public MavenPluginJavaPrerequisiteChecker(VersionScheme versionScheme) {
        this.versionScheme = versionScheme;
    }

    @Override
    public void accept(PluginDescriptor pluginDescriptor) {

                    missingParameters.put(param.getName(), param);
                }
            }
        }
    }

    public Collection<Parameter> getMissingParameters() {
        return missingParameters.values();
    }

    @Override
    public void notifyFieldChangeUsingSetter(String fieldName, Object value, Object target) {
        delegate.notifyFieldChangeUsingSetter(fieldName, value, target);

    }

    @Override
    public NodePointer getNodePointer() {
        if (position == 0) {
            setPosition(1);
        }
        return (attribute == null) ? null : new Xpp3DomAttributePointer(parent, attribute);
    }

    @Override
    public int getPosition() {
        return position;
    }

    @Override
    public boolean setPosition(int position) {

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//