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rozzarozza
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Added MapCodec
JAVA-2448
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‎bson/src/main/org/bson/codecs/MapCodec.java

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/*
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* Copyright (c) 2008-2014 MongoDB, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.bson.codecs;
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import org.bson.BsonBinarySubType;
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import org.bson.BsonDocument;
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import org.bson.BsonDocumentWriter;
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import org.bson.BsonReader;
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import org.bson.BsonType;
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import org.bson.BsonValue;
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import org.bson.BsonWriter;
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import org.bson.Document;
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import org.bson.Transformer;
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import org.bson.codecs.configuration.CodecRegistry;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Map;
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import java.util.UUID;
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import static java.util.Arrays.asList;
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import static org.bson.assertions.Assertions.notNull;
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import static org.bson.codecs.configuration.CodecRegistries.fromProviders;
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/**
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* A Codec for Document instances.
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*
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* @see org.bson.Document
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* @since 3.0
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*/
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public class DocumentCodec implements CollectibleCodec<Document> {
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private static final String ID_FIELD_NAME = "_id";
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private static final CodecRegistry DEFAULT_REGISTRY = fromProviders(asList(new ValueCodecProvider(),
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new BsonValueCodecProvider(),
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new DocumentCodecProvider()));
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private static final BsonTypeClassMap DEFAULT_BSON_TYPE_CLASS_MAP = new BsonTypeClassMap();
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private final BsonTypeCodecMap bsonTypeCodecMap;
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private final CodecRegistry registry;
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private final IdGenerator idGenerator;
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private final Transformer valueTransformer;
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/**
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* Construct a new instance with a default {@code CodecRegistry} and
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*/
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public DocumentCodec() {
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this(DEFAULT_REGISTRY, DEFAULT_BSON_TYPE_CLASS_MAP);
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}
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/**
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* Construct a new instance with the given registry and BSON type class map.
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*
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* @param registry the registry
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* @param bsonTypeClassMap the BSON type class map
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*/
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public DocumentCodec(final CodecRegistry registry, final BsonTypeClassMap bsonTypeClassMap) {
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this(registry, bsonTypeClassMap, null);
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}
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/**
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* Construct a new instance with the given registry and BSON type class map. The transformer is applied as a last step when decoding
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* values, which allows users of this codec to control the decoding process. For example, a user of this class could substitute a
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* value decoded as a Document with an instance of a special purpose class (e.g., one representing a DBRef in MongoDB).
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*
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* @param registry the registry
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* @param bsonTypeClassMap the BSON type class map
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* @param valueTransformer the value transformer to use as a final step when decoding the value of any field in the document
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*/
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public DocumentCodec(final CodecRegistry registry, final BsonTypeClassMap bsonTypeClassMap, final Transformer valueTransformer) {
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this.registry = notNull("registry", registry);
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this.bsonTypeCodecMap = new BsonTypeCodecMap(notNull("bsonTypeClassMap", bsonTypeClassMap), registry);
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this.idGenerator = new ObjectIdGenerator();
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this.valueTransformer = valueTransformer != null ? valueTransformer : new Transformer() {
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@Override
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public Object transform(final Object value) {
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return value;
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}
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};
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}
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@Override
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public boolean documentHasId(final Document document) {
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return document.containsKey(ID_FIELD_NAME);
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}
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@Override
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public BsonValue getDocumentId(final Document document) {
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if (!documentHasId(document)) {
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throw new IllegalStateException("The document does not contain an _id");
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}
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Object id = document.get(ID_FIELD_NAME);
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if (id instanceof BsonValue) {
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return (BsonValue) id;
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}
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BsonDocument idHoldingDocument = new BsonDocument();
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BsonWriter writer = new BsonDocumentWriter(idHoldingDocument);
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writer.writeStartDocument();
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writer.writeName(ID_FIELD_NAME);
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writeValue(writer, EncoderContext.builder().build(), id);
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writer.writeEndDocument();
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return idHoldingDocument.get(ID_FIELD_NAME);
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}
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@Override
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public Document generateIdIfAbsentFromDocument(final Document document) {
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if (!documentHasId(document)) {
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document.put(ID_FIELD_NAME, idGenerator.generate());
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}
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return document;
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}
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@Override
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public void encode(final BsonWriter writer, final Document document, final EncoderContext encoderContext) {
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writeMap(writer, document, encoderContext);
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}
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@Override
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public Document decode(final BsonReader reader, final DecoderContext decoderContext) {
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Document document = new Document();
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reader.readStartDocument();
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while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
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String fieldName = reader.readName();
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document.put(fieldName, readValue(reader, decoderContext));
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}
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reader.readEndDocument();
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return document;
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}
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@Override
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public Class<Document> getEncoderClass() {
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return Document.class;
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}
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private void beforeFields(final BsonWriter bsonWriter, final EncoderContext encoderContext, final Map<String, Object> document) {
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if (encoderContext.isEncodingCollectibleDocument() && document.containsKey(ID_FIELD_NAME)) {
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bsonWriter.writeName(ID_FIELD_NAME);
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writeValue(bsonWriter, encoderContext, document.get(ID_FIELD_NAME));
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}
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}
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private boolean skipField(final EncoderContext encoderContext, final String key) {
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return encoderContext.isEncodingCollectibleDocument() && key.equals(ID_FIELD_NAME);
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}
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@SuppressWarnings({"unchecked", "rawtypes"})
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private void writeValue(final BsonWriter writer, final EncoderContext encoderContext, final Object value) {
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if (value == null) {
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writer.writeNull();
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} else if (value instanceof Iterable) {
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writeIterable(writer, (Iterable<Object>) value, encoderContext.getChildContext());
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} else if (value instanceof Map) {
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writeMap(writer, (Map<String, Object>) value, encoderContext.getChildContext());
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} else {
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Codec codec = registry.get(value.getClass());
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encoderContext.encodeWithChildContext(codec, writer, value);
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}
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}
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private void writeMap(final BsonWriter writer, final Map<String, Object> map, final EncoderContext encoderContext) {
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writer.writeStartDocument();
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beforeFields(writer, encoderContext, map);
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for (final Map.Entry<String, Object> entry : map.entrySet()) {
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if (skipField(encoderContext, entry.getKey())) {
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continue;
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}
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writer.writeName(entry.getKey());
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writeValue(writer, encoderContext, entry.getValue());
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}
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writer.writeEndDocument();
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}
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private void writeIterable(final BsonWriter writer, final Iterable<Object> list, final EncoderContext encoderContext) {
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writer.writeStartArray();
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for (final Object value : list) {
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writeValue(writer, encoderContext, value);
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}
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writer.writeEndArray();
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}
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private Object readValue(final BsonReader reader, final DecoderContext decoderContext) {
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BsonType bsonType = reader.getCurrentBsonType();
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if (bsonType == BsonType.NULL) {
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reader.readNull();
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return null;
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} else if (bsonType == BsonType.ARRAY) {
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return readList(reader, decoderContext);
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} else if (bsonType == BsonType.BINARY && BsonBinarySubType.isUuid(reader.peekBinarySubType()) && reader.peekBinarySize() == 16) {
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return registry.get(UUID.class).decode(reader, decoderContext);
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}
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return valueTransformer.transform(bsonTypeCodecMap.get(bsonType).decode(reader, decoderContext));
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}
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private List<Object> readList(final BsonReader reader, final DecoderContext decoderContext) {
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reader.readStartArray();
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List<Object> list = new ArrayList<Object>();
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while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
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list.add(readValue(reader, decoderContext));
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}
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reader.readEndArray();
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return list;
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}
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}

‎bson/src/main/org/bson/codecs/MapCodecProvider.java

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/*
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* Copyright (c) 2008-2014 MongoDB, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.bson.codecs;
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import org.bson.Document;
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import org.bson.Transformer;
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import org.bson.codecs.configuration.CodecProvider;
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import org.bson.codecs.configuration.CodecRegistry;
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import org.bson.types.CodeWithScope;
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import static org.bson.assertions.Assertions.notNull;
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/**
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* A {@code CodecProvider} for the Document class and all the default Codec implementations on which it depends.
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*
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* @since 3.0
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*/
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public class DocumentCodecProvider implements CodecProvider {
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private final BsonTypeClassMap bsonTypeClassMap;
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private final Transformer valueTransformer;
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/**
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* Construct a new instance with a default {@code BsonTypeClassMap}.
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*/
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public DocumentCodecProvider() {
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this(new BsonTypeClassMap());
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}
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/**
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* Construct a new instance with a default {@code BsonTypeClassMap} and the given {@code Transformer}. The transformer is used by the
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* DocumentCodec as a last step when decoding values.
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*
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* @param valueTransformer the value transformer for decoded values
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* @see org.bson.codecs.DocumentCodec#DocumentCodec(org.bson.codecs.configuration.CodecRegistry, BsonTypeClassMap, org.bson.Transformer)
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*/
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public DocumentCodecProvider(final Transformer valueTransformer) {
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this(new BsonTypeClassMap(), valueTransformer);
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}
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/**
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* Construct a new instance with the given instance of {@code BsonTypeClassMap}.
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*
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* @param bsonTypeClassMap the non-null {@code BsonTypeClassMap} with which to construct instances of {@code DocumentCodec} and {@code
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* ListCodec}
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*/
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public DocumentCodecProvider(final BsonTypeClassMap bsonTypeClassMap) {
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this(bsonTypeClassMap, null);
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}
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/**
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* Construct a new instance with the given instance of {@code BsonTypeClassMap}.
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*
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* @param bsonTypeClassMap the non-null {@code BsonTypeClassMap} with which to construct instances of {@code DocumentCodec} and {@code
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* ListCodec}.
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* @param valueTransformer the value transformer for decoded values
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*/
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public DocumentCodecProvider(final BsonTypeClassMap bsonTypeClassMap, final Transformer valueTransformer) {
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this.bsonTypeClassMap = notNull("bsonTypeClassMap", bsonTypeClassMap);
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this.valueTransformer = valueTransformer;
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}
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@Override
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@SuppressWarnings("unchecked")
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public <T> Codec<T> get(final Class<T> clazz, final CodecRegistry registry) {
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if (clazz == CodeWithScope.class) {
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return (Codec<T>) new CodeWithScopeCodec(registry.get(Document.class));
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}
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if (clazz == Document.class) {
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return (Codec<T>) new DocumentCodec(registry, bsonTypeClassMap, valueTransformer);
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}
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return null;
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}
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@Override
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public boolean equals(final Object o) {
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if (this == o) {
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return true;
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}
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if (o == null || getClass() != o.getClass()) {
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return false;
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}
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DocumentCodecProvider that = (DocumentCodecProvider) o;
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if (!bsonTypeClassMap.equals(that.bsonTypeClassMap)) {
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return false;
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}
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if (valueTransformer != null ? !valueTransformer.equals(that.valueTransformer) : that.valueTransformer != null) {
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return false;
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}
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return true;
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}
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@Override
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public int hashCode() {
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int result = bsonTypeClassMap.hashCode();
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result = 31 * result + (valueTransformer != null ? valueTransformer.hashCode() : 0);
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return result;
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}
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}

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