org.terracotta.context.RootNode Maven / Gradle / Ivy

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A statistics framework used inside Ehcache and the Terracotta products

There is a newer version: 2.1.3

/*
 * All content copyright Terracotta, Inc., unless otherwise indicated.
 *
 * Licensed 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.
 */
package org.terracotta.context;

import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;

class RootNode extends AbstractTreeNode {

  private final Collection listeners = new CopyOnWriteArrayList<>();

  @Override
  void addedParent(AbstractTreeNode child) {
    throw new IllegalStateException();
  }

  @Override
  void removedParent(AbstractTreeNode child) {
    throw new IllegalStateException();
  }

  @Override
  Set getAncestors() {
    return Collections.emptySet();
  }

  @Override
  Collection getListeners() {
    return Collections.unmodifiableCollection(listeners);
  }

  public void addListener(ContextListener listener) {
    listeners.add(listener);
  }

  public void removeListener(ContextListener listener) {
    listeners.remove(listener);
  }

  @Override
  public ContextElement getContext() {
    throw new IllegalStateException();
  }

  @Override
  public Collection> getPaths() {
    return Collections.singleton(Collections.emptyList());
  }
}