apps/logstream/src/main/java/com/datatorrent/apps/logstream/PropertyRegistry/PropertyRegistry.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.datatorrent.apps.logstream.PropertyRegistry;

/**
 * Interface for property registry which can be implemented and shared across the dag
 * Properties can be added to the registry during dag setup and then be accessible in all
 * interested operators to look them up.
 *
 * @param <T>
 * @since 0.9.4
 */
public interface PropertyRegistry<T>
{
  /**
   * binds a given name and value, assigns a unique index to the name value pair and returns it
   * @param name
   * @param value
   * @return
   */
  public int bind(T name, T value);

  /**
   * Returns the index of name value pair if exists, else returns -1
   * @param name
   * @param value
   * @return
   */
  public int getIndex(T name, T value);

  /**
   * Returns the name associated with given index
   * @param register
   * @return
   */
  public T lookupName(int register);

  /**
   * Returns the value associated with given index
   * @param register
   * @return
   */
  public T lookupValue(int register);

  /**
   * Returns a list of values associated with given name
   * @param name
   * @return
   */
  public T[] list(String name);
}