/* * 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.cassandra.service.pager; import java.nio.ByteBuffer; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.cassandra.db.*; import org.apache.cassandra.db.rows.*; import org.apache.cassandra.db.filter.*; /** * Common interface to single partition queries (by slice and by name). * * For use by MultiPartitionPager. */ public class SinglePartitionPager extends AbstractQueryPager { private static final Logger logger = LoggerFactory.getLogger(SinglePartitionPager.class); private final SinglePartitionReadCommand command; private volatile PagingState.RowMark lastReturned; public SinglePartitionPager(SinglePartitionReadCommand command, PagingState state, int protocolVersion) { super(command, protocolVersion); this.command = command; if (state != null) { lastReturned = state.rowMark; restoreState(command.partitionKey(), state.remaining, state.remainingInPartition); } } public ByteBuffer key() { return command.partitionKey().getKey(); } public DataLimits limits() { return command.limits(); } public PagingState state() { return lastReturned == null ? null : new PagingState(null, lastReturned, maxRemaining(), remainingInPartition()); } protected ReadCommand nextPageReadCommand(int pageSize) { return command.forPaging(lastReturned == null ? null : lastReturned.clustering(command.metadata()), pageSize); } protected void recordLast(DecoratedKey key, Row last) { if (last != null && last.clustering() != Clustering.STATIC_CLUSTERING) lastReturned = PagingState.RowMark.create(command.metadata(), last, protocolVersion); } protected boolean isPreviouslyReturnedPartition(DecoratedKey key) { return lastReturned != null; } }