StandardResource.java

package sk.stuba.fiit.perconik.core.resources;

import java.util.Collection;

import sk.stuba.fiit.perconik.core.Listener;
import sk.stuba.fiit.perconik.core.Resource;
import sk.stuba.fiit.perconik.core.annotations.Unsupported;

import static com.google.common.collect.Lists.newArrayListWithCapacity;

class StandardResource<L extends Listener> extends AbstractResource<L> {
  final Pool<L> pool;

  StandardResource(final Pool<L> pool) {
    super(pool.toString().replaceFirst("Pool\\z", "Resource"));

    this.pool = pool;
  }

  static final <L extends Listener> Resource<L> newInstance(final Pool<L> pool, final boolean unsupported) {
    return unsupported ? new UnsupportedResource<>(pool) : new StandardResource<>(pool);
  }

  public final void register(final L listener) {
    this.pool.add(listener);
  }

  public final void unregister(final L listener) {
    this.pool.remove(listener);
  }

  public final <U extends Listener> Collection<U> registered(final Class<U> type) {
    Collection<L> listeners = this.pool.toCollection();
    Collection<U> filtered = newArrayListWithCapacity(listeners.size());

    for (L listener: listeners) {
      if (type.isInstance(listener)) {
        filtered.add(type.cast(listener));
      }
    }

    return filtered;
  }

  public final boolean registered(final Listener listener) {
    return this.pool.contains(listener);
  }
}

@Unsupported
class UnsupportedResource<L extends Listener> extends StandardResource<L> {
  UnsupportedResource(final Pool<L> pool) {
    super(pool);
  }
}