/*
* 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 org.apache.beam.sdk.state;
import org.apache.beam.sdk.annotations.Experimental;
import org.apache.beam.sdk.annotations.Experimental.Kind;
/**
* A {@link ReadableState} cell containing a bag of values. Items can be added to the bag and the
* contents read out.
*
* <p>Implementations of this form of state are expected to implement {@link #add} efficiently, not
* via a sequence of read-modify-write.
*
* @param <T> The type of elements in the bag.
*/
@Experimental(Kind.STATE)
public interface BagState<T> extends GroupingState<T, Iterable<T>> {
@Override
BagState<T> readLater();
}