/*
* 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 com.facebook.presto.example;
import com.facebook.presto.spi.RecordCursor;
import com.facebook.presto.spi.type.Type;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.base.Throwables;
import com.google.common.io.CountingInputStream;
import com.google.common.io.InputSupplier;
import io.airlift.slice.Slice;
import io.airlift.slice.Slices;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.List;
import static com.facebook.presto.spi.type.BigintType.BIGINT;
import static com.facebook.presto.spi.type.BooleanType.BOOLEAN;
import static com.facebook.presto.spi.type.DoubleType.DOUBLE;
import static com.facebook.presto.spi.type.VarcharType.VARCHAR;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.io.ByteStreams.asByteSource;
public class ExampleRecordCursor
implements RecordCursor
{
private static final Splitter LINE_SPLITTER = Splitter.on(",").trimResults();
private final List<ExampleColumnHandle> columnHandles;
private final int[] fieldToColumnIndex;
private final Iterator<String> lines;
private final long totalBytes;
private List<String> fields;
public ExampleRecordCursor(List<ExampleColumnHandle> columnHandles, InputSupplier<InputStream> inputStreamSupplier)
{
this.columnHandles = columnHandles;
fieldToColumnIndex = new int[columnHandles.size()];
for (int i = 0; i < columnHandles.size(); i++) {
ExampleColumnHandle columnHandle = columnHandles.get(i);
fieldToColumnIndex[i] = columnHandle.getOrdinalPosition();
}
try (CountingInputStream input = new CountingInputStream(inputStreamSupplier.getInput())) {
lines = asByteSource(inputStreamSupplier).asCharSource(StandardCharsets.UTF_8).readLines().iterator();
totalBytes = input.getCount();
}
catch (IOException e) {
throw Throwables.propagate(e);
}
}
@Override
public long getTotalBytes()
{
return totalBytes;
}
@Override
public long getCompletedBytes()
{
return totalBytes;
}
@Override
public long getReadTimeNanos()
{
return 0;
}
@Override
public Type getType(int field)
{
checkArgument(field < columnHandles.size(), "Invalid field index");
return columnHandles.get(field).getColumnType();
}
@Override
public boolean advanceNextPosition()
{
if (!lines.hasNext()) {
return false;
}
String line = lines.next();
fields = LINE_SPLITTER.splitToList(line);
return true;
}
private String getFieldValue(int field)
{
checkState(fields != null, "Cursor has not been advanced yet");
int columnIndex = fieldToColumnIndex[field];
return fields.get(columnIndex);
}
@Override
public boolean getBoolean(int field)
{
checkFieldType(field, BOOLEAN);
return Boolean.parseBoolean(getFieldValue(field));
}
@Override
public long getLong(int field)
{
checkFieldType(field, BIGINT);
return Long.parseLong(getFieldValue(field));
}
@Override
public double getDouble(int field)
{
checkFieldType(field, DOUBLE);
return Double.parseDouble(getFieldValue(field));
}
@Override
public Slice getSlice(int field)
{
checkFieldType(field, VARCHAR);
return Slices.utf8Slice(getFieldValue(field));
}
@Override
public boolean isNull(int field)
{
checkArgument(field < columnHandles.size(), "Invalid field index");
return Strings.isNullOrEmpty(getFieldValue(field));
}
private void checkFieldType(int field, Type expected)
{
Type actual = getType(field);
checkArgument(actual.equals(expected), "Expected field %s to be type %s but is %s", field, expected, actual);
}
@Override
public void close()
{
}
}