org.neo4j.driver.internal.InternalStatementResult Maven / Gradle / Ivy
/**
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* 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.neo4j.driver.internal;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import org.neo4j.driver.internal.spi.Connection;
import org.neo4j.driver.internal.spi.StreamCollector;
import org.neo4j.driver.internal.summary.SummaryBuilder;
import org.neo4j.driver.v1.Record;
import org.neo4j.driver.v1.Statement;
import org.neo4j.driver.v1.StatementResult;
import org.neo4j.driver.v1.Value;
import org.neo4j.driver.v1.exceptions.ClientException;
import org.neo4j.driver.v1.exceptions.NoSuchRecordException;
import org.neo4j.driver.v1.summary.Notification;
import org.neo4j.driver.v1.summary.Plan;
import org.neo4j.driver.v1.summary.ProfiledPlan;
import org.neo4j.driver.v1.summary.ResultSummary;
import org.neo4j.driver.v1.summary.StatementType;
import org.neo4j.driver.v1.summary.SummaryCounters;
import org.neo4j.driver.v1.util.Function;
import org.neo4j.driver.v1.util.Functions;
import static java.util.Collections.emptyList;
public class InternalStatementResult implements StatementResult
{
private final Connection connection;
private final StreamCollector runResponseCollector;
private final StreamCollector pullAllResponseCollector;
private final Queue recordBuffer = new LinkedList<>();
private List keys = null;
private ResultSummary summary = null;
private long position = -1;
private boolean done = false;
public InternalStatementResult( Connection connection, Statement statement )
{
this.connection = connection;
this.runResponseCollector = newRunResponseCollector();
this.pullAllResponseCollector = newPullAllResponseCollector( statement );
}
private StreamCollector newRunResponseCollector()
{
return new StreamCollector()
{
@Override
public void keys( String[] names )
{
keys = Arrays.asList( names );
}
@Override
public void record( Value[] fields ) {}
@Override
public void statementType( StatementType type ) {}
@Override
public void statementStatistics( SummaryCounters statistics ) {}
@Override
public void plan( Plan plan ) {}
@Override
public void profile( ProfiledPlan plan ) {}
@Override
public void notifications( List notifications ) {}
@Override
public void done()
{
if ( keys == null )
{
keys = new ArrayList<>();
}
}
};
}
private StreamCollector newPullAllResponseCollector( Statement statement )
{
final SummaryBuilder summaryBuilder = new SummaryBuilder( statement );
return new StreamCollector()
{
@Override
public void keys( String[] names ) {}
@Override
public void record( Value[] fields )
{
recordBuffer.add( new InternalRecord( keys, fields ) );
}
@Override
public void statementType( StatementType type )
{
summaryBuilder.statementType( type );
}
@Override
public void statementStatistics( SummaryCounters statistics )
{
summaryBuilder.statementStatistics( statistics );
}
@Override
public void plan( Plan plan )
{
summaryBuilder.plan( plan );
}
@Override
public void profile( ProfiledPlan plan )
{
summaryBuilder.profile( plan );
}
@Override
public void notifications( List notifications )
{
summaryBuilder.notifications( notifications );
}
@Override
public void done() {
summary = summaryBuilder.build();
done = true;
}
};
}
StreamCollector runResponseCollector()
{
return runResponseCollector;
}
StreamCollector pullAllResponseCollector()
{
return pullAllResponseCollector;
}
@Override
public List keys()
{
if ( keys == null )
{
tryFetchNext();
}
return keys;
}
@Override
public boolean hasNext()
{
return tryFetchNext();
}
@Override
public Record next()
{
// Implementation note:
// We've chosen to use Iterator over a cursor-based version,
// after tests show escape analysis will eliminate short-lived allocations
// in a way that makes the two equivalent in performance.
// To get the intended benefit, we need to allocate Record in this method,
// and have it copy out its fields from some lower level data structure.
if ( tryFetchNext() )
{
position += 1;
return recordBuffer.poll();
}
else
{
throw new NoSuchRecordException( "No more records" );
}
}
@Override
public Record single()
{
if ( hasNext() )
{
Record single = next();
boolean hasMoreThanOne = hasNext();
consume();
if ( hasMoreThanOne )
{
throw new NoSuchRecordException( "Expected a result with a single record, but this result contains at least one more. " +
"Ensure your query returns only one record, or use `first` instead of `single` if " +
"you do not care about the number of records in the result." );
}
return single;
}
else
{
throw new NoSuchRecordException( "Cannot retrieve a single record, because this result is empty." );
}
}
@Override
public Record peek()
{
if ( tryFetchNext() )
{
return recordBuffer.peek();
}
else
{
throw new NoSuchRecordException( "Cannot peek past the last record" );
}
}
@Override
public List list()
{
return list( Functions.identity() );
}
@Override
public List list( Function mapFunction )
{
if ( hasNext() )
{
List result = new ArrayList<>();
do
{
result.add( mapFunction.apply( next() ) );
}
while ( hasNext() );
return result;
}
else
{
return emptyList();
}
}
@Override
public ResultSummary consume()
{
if ( done )
{
recordBuffer.clear();
}
else
{
do
{
connection.receiveOne();
recordBuffer.clear();
}
while ( !done );
}
return summary;
}
@Override
public void remove()
{
throw new ClientException( "Removing records from a result is not supported." );
}
private boolean tryFetchNext()
{
while ( recordBuffer.isEmpty() )
{
if ( done )
{
return false;
}
connection.receiveOne();
}
return true;
}
}
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