StructTypeID.java
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上传日期:2018-01-08
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文件大小:5k
- /**
- * 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.hadoop.record.meta;
- import java.io.IOException;
- import java.util.*;
- import org.apache.hadoop.record.RecordInput;
- import org.apache.hadoop.record.RecordOutput;
- /**
- * Represents typeID for a struct
- */
- public class StructTypeID extends TypeID {
- private ArrayList<FieldTypeInfo> typeInfos = new ArrayList<FieldTypeInfo>();
-
- StructTypeID() {
- super(RIOType.STRUCT);
- }
-
- /**
- * Create a StructTypeID based on the RecordTypeInfo of some record
- */
- public StructTypeID(RecordTypeInfo rti) {
- super(RIOType.STRUCT);
- typeInfos.addAll(rti.getFieldTypeInfos());
- }
- void add (FieldTypeInfo ti) {
- typeInfos.add(ti);
- }
-
- public Collection<FieldTypeInfo> getFieldTypeInfos() {
- return typeInfos;
- }
-
- /*
- * return the StructTypeiD, if any, of the given field
- */
- StructTypeID findStruct(String name) {
- // walk through the list, searching. Not the most efficient way, but this
- // in intended to be used rarely, so we keep it simple.
- // As an optimization, we can keep a hashmap of record name to its RTI, for later.
- for (FieldTypeInfo ti : typeInfos) {
- if ((0 == ti.getFieldID().compareTo(name)) && (ti.getTypeID().getTypeVal() == RIOType.STRUCT)) {
- return (StructTypeID) ti.getTypeID();
- }
- }
- return null;
- }
-
- void write(RecordOutput rout, String tag) throws IOException {
- rout.writeByte(typeVal, tag);
- writeRest(rout, tag);
- }
- /*
- * Writes rest of the struct (excluding type value).
- * As an optimization, this method is directly called by RTI
- * for the top level record so that we don't write out the byte
- * indicating that this is a struct (since top level records are
- * always structs).
- */
- void writeRest(RecordOutput rout, String tag) throws IOException {
- rout.writeInt(typeInfos.size(), tag);
- for (FieldTypeInfo ti : typeInfos) {
- ti.write(rout, tag);
- }
- }
- /*
- * deserialize ourselves. Called by RTI.
- */
- void read(RecordInput rin, String tag) throws IOException {
- // number of elements
- int numElems = rin.readInt(tag);
- for (int i=0; i<numElems; i++) {
- typeInfos.add(genericReadTypeInfo(rin, tag));
- }
- }
-
- // generic reader: reads the next TypeInfo object from stream and returns it
- private FieldTypeInfo genericReadTypeInfo(RecordInput rin, String tag) throws IOException {
- String fieldName = rin.readString(tag);
- TypeID id = genericReadTypeID(rin, tag);
- return new FieldTypeInfo(fieldName, id);
- }
-
- // generic reader: reads the next TypeID object from stream and returns it
- private TypeID genericReadTypeID(RecordInput rin, String tag) throws IOException {
- byte typeVal = rin.readByte(tag);
- switch (typeVal) {
- case TypeID.RIOType.BOOL:
- return TypeID.BoolTypeID;
- case TypeID.RIOType.BUFFER:
- return TypeID.BufferTypeID;
- case TypeID.RIOType.BYTE:
- return TypeID.ByteTypeID;
- case TypeID.RIOType.DOUBLE:
- return TypeID.DoubleTypeID;
- case TypeID.RIOType.FLOAT:
- return TypeID.FloatTypeID;
- case TypeID.RIOType.INT:
- return TypeID.IntTypeID;
- case TypeID.RIOType.LONG:
- return TypeID.LongTypeID;
- case TypeID.RIOType.MAP:
- {
- TypeID tIDKey = genericReadTypeID(rin, tag);
- TypeID tIDValue = genericReadTypeID(rin, tag);
- return new MapTypeID(tIDKey, tIDValue);
- }
- case TypeID.RIOType.STRING:
- return TypeID.StringTypeID;
- case TypeID.RIOType.STRUCT:
- {
- StructTypeID stID = new StructTypeID();
- int numElems = rin.readInt(tag);
- for (int i=0; i<numElems; i++) {
- stID.add(genericReadTypeInfo(rin, tag));
- }
- return stID;
- }
- case TypeID.RIOType.VECTOR:
- {
- TypeID tID = genericReadTypeID(rin, tag);
- return new VectorTypeID(tID);
- }
- default:
- // shouldn't be here
- throw new IOException("Unknown type read");
- }
- }
- }