[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | package org.apache.hadoop.record.meta; |
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| 20 | |
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| 21 | import java.io.IOException; |
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| 22 | import java.util.*; |
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| 23 | |
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| 24 | import org.apache.hadoop.record.RecordInput; |
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| 25 | import org.apache.hadoop.record.RecordOutput; |
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| 26 | |
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| 27 | |
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| 28 | /** |
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| 29 | * A record's Type Information object which can read/write itself. |
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| 30 | * |
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| 31 | * Type information for a record comprises metadata about the record, |
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| 32 | * as well as a collection of type information for each field in the record. |
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| 33 | */ |
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| 34 | public class RecordTypeInfo extends org.apache.hadoop.record.Record |
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| 35 | { |
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| 36 | |
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| 37 | private String name; |
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| 38 | // A RecordTypeInfo is really just a wrapper around StructTypeID |
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| 39 | StructTypeID sTid; |
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| 40 | // A RecordTypeInfo object is just a collection of TypeInfo objects for each of its fields. |
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| 41 | //private ArrayList<FieldTypeInfo> typeInfos = new ArrayList<FieldTypeInfo>(); |
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| 42 | // we keep a hashmap of struct/record names and their type information, as we need it to |
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| 43 | // set filters when reading nested structs. This map is used during deserialization. |
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| 44 | //private Map<String, RecordTypeInfo> structRTIs = new HashMap<String, RecordTypeInfo>(); |
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| 45 | |
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| 46 | /** |
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| 47 | * Create an empty RecordTypeInfo object. |
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| 48 | */ |
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| 49 | public RecordTypeInfo() { |
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| 50 | sTid = new StructTypeID(); |
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| 51 | } |
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| 52 | |
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| 53 | /** |
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| 54 | * Create a RecordTypeInfo object representing a record with the given name |
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| 55 | * @param name Name of the record |
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| 56 | */ |
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| 57 | public RecordTypeInfo(String name) { |
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| 58 | this.name = name; |
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| 59 | sTid = new StructTypeID(); |
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| 60 | } |
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| 61 | |
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| 62 | /* |
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| 63 | * private constructor |
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| 64 | */ |
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| 65 | private RecordTypeInfo(String name, StructTypeID stid) { |
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| 66 | this.sTid = stid; |
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| 67 | this.name = name; |
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| 68 | } |
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| 69 | |
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| 70 | /** |
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| 71 | * return the name of the record |
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| 72 | */ |
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| 73 | public String getName() { |
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| 74 | return name; |
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| 75 | } |
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| 76 | |
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| 77 | /** |
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| 78 | * set the name of the record |
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| 79 | */ |
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| 80 | public void setName(String name) { |
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| 81 | this.name = name; |
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| 82 | } |
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| 83 | |
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| 84 | /** |
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| 85 | * Add a field. |
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| 86 | * @param fieldName Name of the field |
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| 87 | * @param tid Type ID of the field |
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| 88 | */ |
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| 89 | public void addField(String fieldName, TypeID tid) { |
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| 90 | sTid.getFieldTypeInfos().add(new FieldTypeInfo(fieldName, tid)); |
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| 91 | } |
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| 92 | |
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| 93 | private void addAll(Collection<FieldTypeInfo> tis) { |
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| 94 | sTid.getFieldTypeInfos().addAll(tis); |
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| 95 | } |
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| 96 | |
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| 97 | /** |
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| 98 | * Return a collection of field type infos |
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| 99 | */ |
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| 100 | public Collection<FieldTypeInfo> getFieldTypeInfos() { |
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| 101 | return sTid.getFieldTypeInfos(); |
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| 102 | } |
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| 103 | |
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| 104 | /** |
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| 105 | * Return the type info of a nested record. We only consider nesting |
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| 106 | * to one level. |
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| 107 | * @param name Name of the nested record |
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| 108 | */ |
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| 109 | public RecordTypeInfo getNestedStructTypeInfo(String name) { |
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| 110 | StructTypeID stid = sTid.findStruct(name); |
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| 111 | if (null == stid) return null; |
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| 112 | return new RecordTypeInfo(name, stid); |
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| 113 | } |
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| 114 | |
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| 115 | /** |
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| 116 | * Serialize the type information for a record |
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| 117 | */ |
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| 118 | public void serialize(RecordOutput rout, String tag) throws IOException { |
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| 119 | // write out any header, version info, here |
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| 120 | rout.startRecord(this, tag); |
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| 121 | rout.writeString(name, tag); |
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| 122 | sTid.writeRest(rout, tag); |
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| 123 | rout.endRecord(this, tag); |
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| 124 | } |
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| 125 | |
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| 126 | /** |
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| 127 | * Deserialize the type information for a record |
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| 128 | */ |
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| 129 | public void deserialize(RecordInput rin, String tag) throws IOException { |
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| 130 | // read in any header, version info |
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| 131 | rin.startRecord(tag); |
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| 132 | // name |
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| 133 | this.name = rin.readString(tag); |
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| 134 | sTid.read(rin, tag); |
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| 135 | rin.endRecord(tag); |
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| 136 | } |
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| 137 | |
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| 138 | /** |
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| 139 | * This class doesn't implement Comparable as it's not meant to be used |
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| 140 | * for anything besides de/serializing. |
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| 141 | * So we always throw an exception. |
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| 142 | * Not implemented. Always returns 0 if another RecordTypeInfo is passed in. |
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| 143 | */ |
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| 144 | public int compareTo (final Object peer_) throws ClassCastException { |
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| 145 | if (!(peer_ instanceof RecordTypeInfo)) { |
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| 146 | throw new ClassCastException("Comparing different types of records."); |
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| 147 | } |
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| 148 | throw new UnsupportedOperationException("compareTo() is not supported"); |
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| 149 | } |
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| 150 | } |
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| 151 | |
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