/*
* 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 parquet.format.event;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TField;
import org.apache.thrift.protocol.TList;
import org.apache.thrift.protocol.TMap;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.protocol.TSet;
import org.apache.thrift.protocol.TType;
import parquet.format.event.TypedConsumer.ListConsumer;
import parquet.format.event.TypedConsumer.MapConsumer;
import parquet.format.event.TypedConsumer.SetConsumer;
/**
* Event based reader for Thrift
*
* @author Julien Le Dem
*
*/
public final class EventBasedThriftReader {
private final TProtocol protocol;
/**
* @param protocol the protocol to read from
*/
public EventBasedThriftReader(TProtocol protocol) {
this.protocol = protocol;
}
/**
* reads a Struct from the underlying protocol and passes the field events to the FieldConsumer
* @param c the field consumer
* @throws TException
*/
public void readStruct(FieldConsumer c) throws TException {
protocol.readStructBegin();
readStructContent(c);
protocol.readStructEnd();
}
/**
* reads the content of a struct (fields) from the underlying protocol and passes the events to c
* @param c the field consumer
* @throws TException
*/
public void readStructContent(FieldConsumer c) throws TException {
TField field;
while (true) {
field = protocol.readFieldBegin();
if (field.type == TType.STOP) {
break;
}
c.consumeField(protocol, this, field.id, field.type);
}
}
/**
* reads the set content (elements) from the underlying protocol and passes the events to the set event consumer
* @param eventConsumer the consumer
* @param tSet the set descriptor
* @throws TException
*/
public void readSetContent(SetConsumer eventConsumer, TSet tSet)
throws TException {
for (int i = 0; i < tSet.size; i++) {
eventConsumer.consumeElement(protocol, this, tSet.elemType);
}
}
/**
* reads the map content (key values) from the underlying protocol and passes the events to the map event consumer
* @param eventConsumer the consumer
* @param tMap the map descriptor
* @throws TException
*/
public void readMapContent(MapConsumer eventConsumer, TMap tMap)
throws TException {
for (int i = 0; i < tMap.size; i++) {
eventConsumer.consumeEntry(protocol, this, tMap.keyType, tMap.valueType);
}
}
/**
* reads a key-value pair
* @param keyType the type of the key
* @param keyConsumer the consumer for the key
* @param valueType the type of the value
* @param valueConsumer the consumer for the value
* @throws TException
*/
public void readMapEntry(byte keyType, TypedConsumer keyConsumer, byte valueType, TypedConsumer valueConsumer)
throws TException {
keyConsumer.read(protocol, this, keyType);
valueConsumer.read(protocol, this, valueType);
}
/**
* reads the list content (elements) from the underlying protocol and passes the events to the list event consumer
* @param eventConsumer the consumer
* @param tList the list descriptor
* @throws TException
*/
public void readListContent(ListConsumer eventConsumer, TList tList)
throws TException {
for (int i = 0; i < tList.size; i++) {
eventConsumer.consumeElement(protocol, this, tList.elemType);
}
}
}