com.datastax.dse.driver.internal.core.cql.continuous.DefaultContinuousResultSet Maven / Gradle / Ivy
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* 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.datastax.dse.driver.internal.core.cql.continuous;
import com.datastax.dse.driver.api.core.cql.continuous.ContinuousAsyncResultSet;
import com.datastax.dse.driver.api.core.cql.continuous.ContinuousResultSet;
import com.datastax.oss.driver.api.core.cql.ColumnDefinitions;
import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
import com.datastax.oss.driver.api.core.cql.Row;
import com.datastax.oss.driver.internal.core.util.CountingIterator;
import com.datastax.oss.driver.internal.core.util.concurrent.BlockingOperation;
import com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures;
import edu.umd.cs.findbugs.annotations.NonNull;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import net.jcip.annotations.NotThreadSafe;
/**
* This class is roughly equivalent to {@link
* com.datastax.oss.driver.internal.core.cql.MultiPageResultSet}, except that {@link
* RowIterator#maybeMoveToNextPage()} needs to check for cancellation before fetching the next page.
*/
@NotThreadSafe
public class DefaultContinuousResultSet implements ContinuousResultSet {
private final RowIterator iterator;
private final List executionInfos = new ArrayList<>();
private final ColumnDefinitions columnDefinitions;
public DefaultContinuousResultSet(ContinuousAsyncResultSet firstPage) {
iterator = new RowIterator(firstPage);
columnDefinitions = firstPage.getColumnDefinitions();
executionInfos.add(firstPage.getExecutionInfo());
}
@Override
public void cancel() {
iterator.cancel();
}
@NonNull
@Override
public ColumnDefinitions getColumnDefinitions() {
return columnDefinitions;
}
@NonNull
@Override
public List getExecutionInfos() {
return executionInfos;
}
@NonNull
@Override
public Iterator iterator() {
return iterator;
}
@Override
public boolean isFullyFetched() {
return iterator.isFullyFetched();
}
@Override
public int getAvailableWithoutFetching() {
return iterator.remaining();
}
@Override
public boolean wasApplied() {
return iterator.wasApplied();
}
private class RowIterator extends CountingIterator {
private ContinuousAsyncResultSet currentPage;
private Iterator currentRows;
private boolean cancelled = false;
private RowIterator(ContinuousAsyncResultSet firstPage) {
super(firstPage.remaining());
currentPage = firstPage;
currentRows = firstPage.currentPage().iterator();
}
@Override
protected Row computeNext() {
maybeMoveToNextPage();
return currentRows.hasNext() ? currentRows.next() : endOfData();
}
private void maybeMoveToNextPage() {
if (!cancelled && !currentRows.hasNext() && currentPage.hasMorePages()) {
BlockingOperation.checkNotDriverThread();
ContinuousAsyncResultSet nextPage =
CompletableFutures.getUninterruptibly(currentPage.fetchNextPage());
currentPage = nextPage;
remaining += currentPage.remaining();
currentRows = nextPage.currentPage().iterator();
executionInfos.add(nextPage.getExecutionInfo());
}
}
private boolean isFullyFetched() {
return !currentPage.hasMorePages();
}
private boolean wasApplied() {
return currentPage.wasApplied();
}
private void cancel() {
currentPage.cancel();
cancelled = true;
}
}
}