/**
* 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.drill.exec.store.pojo;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.sql.Timestamp;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.drill.common.exceptions.ExecutionSetupException;
import org.apache.drill.exec.exception.OutOfMemoryException;
import org.apache.drill.exec.exception.SchemaChangeException;
import org.apache.drill.exec.ops.OperatorContext;
import org.apache.drill.exec.physical.impl.OutputMutator;
import org.apache.drill.exec.store.AbstractRecordReader;
import org.apache.drill.exec.store.pojo.Writers.BitWriter;
import org.apache.drill.exec.store.pojo.Writers.DoubleWriter;
import org.apache.drill.exec.store.pojo.Writers.EnumWriter;
import org.apache.drill.exec.store.pojo.Writers.IntWriter;
import org.apache.drill.exec.store.pojo.Writers.LongWriter;
import org.apache.drill.exec.store.pojo.Writers.NBigIntWriter;
import org.apache.drill.exec.store.pojo.Writers.NBooleanWriter;
import org.apache.drill.exec.store.pojo.Writers.NDoubleWriter;
import org.apache.drill.exec.store.pojo.Writers.NIntWriter;
import org.apache.drill.exec.store.pojo.Writers.NTimeStampWriter;
import org.apache.drill.exec.store.pojo.Writers.StringWriter;
import org.apache.drill.exec.testing.ControlsInjector;
import org.apache.drill.exec.testing.ControlsInjectorFactory;
import org.apache.drill.exec.vector.AllocationHelper;
import org.apache.drill.exec.vector.ValueVector;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
public class PojoRecordReader<T> extends AbstractRecordReader implements Iterable<T> {
private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(PojoRecordReader.class);
private static final ControlsInjector injector = ControlsInjectorFactory.getInjector(PojoRecordReader.class);
private final Class<T> pojoClass;
private final List<T> pojoObjects;
private PojoWriter[] writers;
private boolean doCurrent;
private T currentPojo;
private OperatorContext operatorContext;
private Iterator<T> currentIterator;
/**
* TODO: Cleanup the callers to pass the List of POJO objects directly rather than iterator.
* @param pojoClass
* @param iterator
*/
public PojoRecordReader(Class<T> pojoClass, Iterator<T> iterator) {
this.pojoClass = pojoClass;
this.pojoObjects = ImmutableList.copyOf(iterator);
}
@Override
public void setup(OperatorContext context, OutputMutator output) throws ExecutionSetupException {
operatorContext = context;
try {
Field[] fields = pojoClass.getDeclaredFields();
List<PojoWriter> writers = Lists.newArrayList();
for (int i = 0; i < fields.length; i++) {
Field f = fields[i];
if (Modifier.isStatic(f.getModifiers())) {
continue;
}
Class<?> type = f.getType();
PojoWriter w = null;
if(type == int.class) {
w = new IntWriter(f);
} else if(type == Integer.class) {
w = new NIntWriter(f);
} else if(type == Long.class) {
w = new NBigIntWriter(f);
} else if(type == Boolean.class) {
w = new NBooleanWriter(f);
} else if(type == double.class) {
w = new DoubleWriter(f);
} else if(type == Double.class) {
w = new NDoubleWriter(f);
} else if(type.isEnum()) {
w = new EnumWriter(f, output.getManagedBuffer());
} else if(type == boolean.class) {
w = new BitWriter(f);
} else if(type == long.class) {
w = new LongWriter(f);
} else if(type == String.class) {
w = new StringWriter(f, output.getManagedBuffer());
} else if (type == Timestamp.class) {
w = new NTimeStampWriter(f);
} else {
throw new ExecutionSetupException(String.format("PojoRecord reader doesn't yet support conversions from type [%s].", type));
}
writers.add(w);
w.init(output);
}
this.writers = writers.toArray(new PojoWriter[writers.size()]);
} catch(SchemaChangeException e) {
throw new ExecutionSetupException("Failure while setting up schema for PojoRecordReader.", e);
}
currentIterator = pojoObjects.iterator();
}
@Override
public void allocate(Map<String, ValueVector> vectorMap) throws OutOfMemoryException {
for (final ValueVector v : vectorMap.values()) {
AllocationHelper.allocate(v, Character.MAX_VALUE, 50, 10);
}
}
private void allocate() {
for (PojoWriter writer : writers) {
writer.allocate();
}
}
private void setValueCount(int i) {
for (PojoWriter writer : writers) {
writer.setValueCount(i);
}
}
@Override
public int next() {
boolean allocated = false;
injector.injectPause(operatorContext.getExecutionControls(), "read-next", logger);
try {
int i =0;
while (doCurrent || currentIterator.hasNext()) {
if (doCurrent) {
doCurrent = false;
} else {
currentPojo = currentIterator.next();
}
if (!allocated) {
allocate();
allocated = true;
}
for (PojoWriter writer : writers) {
writer.writeField(currentPojo, i);
}
i++;
}
if (i != 0 ) {
setValueCount(i);
}
return i;
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new RuntimeException("Failure while trying to use PojoRecordReader.", e);
}
}
@Override
public Iterator<T> iterator() {
return pojoObjects.iterator();
}
@Override
public void close() {
}
}