org.bson.codecs.pojo.CollectionPropertyCodecProvider Maven / Gradle / Ivy
/*
* Copyright 2008-present MongoDB, Inc.
*
* Licensed 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.bson.codecs.pojo;
import org.bson.BsonReader;
import org.bson.BsonType;
import org.bson.BsonWriter;
import org.bson.codecs.Codec;
import org.bson.codecs.DecoderContext;
import org.bson.codecs.EncoderContext;
import org.bson.codecs.configuration.CodecConfigurationException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import static java.lang.String.format;
final class CollectionPropertyCodecProvider implements PropertyCodecProvider {
@SuppressWarnings({"rawtypes", "unchecked"})
@Override
public Codec get(final TypeWithTypeParameters type, final PropertyCodecRegistry registry) {
if (Collection.class.isAssignableFrom(type.getType()) && type.getTypeParameters().size() == 1) {
return new CollectionCodec(type.getType(), registry.get(type.getTypeParameters().get(0)));
} else {
return null;
}
}
private static class CollectionCodec implements Codec> {
private final Class> encoderClass;
private final Codec codec;
CollectionCodec(final Class> encoderClass, final Codec codec) {
this.encoderClass = encoderClass;
this.codec = codec;
}
@Override
public void encode(final BsonWriter writer, final Collection collection, final EncoderContext encoderContext) {
writer.writeStartArray();
for (final T value : collection) {
if (value == null) {
writer.writeNull();
} else {
codec.encode(writer, value, encoderContext);
}
}
writer.writeEndArray();
}
@Override
public Collection decode(final BsonReader reader, final DecoderContext context) {
Collection collection = getInstance();
reader.readStartArray();
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
if (reader.getCurrentBsonType() == BsonType.NULL) {
collection.add(null);
reader.readNull();
} else {
collection.add(codec.decode(reader, context));
}
}
reader.readEndArray();
return collection;
}
@Override
public Class> getEncoderClass() {
return encoderClass;
}
private Collection getInstance() {
if (encoderClass.isInterface()) {
if (encoderClass.isAssignableFrom(ArrayList.class)) {
return new ArrayList();
} else if (encoderClass.isAssignableFrom(HashSet.class)) {
return new HashSet();
} else {
throw new CodecConfigurationException(format("Unsupported Collection interface of %s!", encoderClass.getName()));
}
}
try {
return encoderClass.getDeclaredConstructor().newInstance();
} catch (final Exception e) {
throw new CodecConfigurationException(e.getMessage(), e);
}
}
}
}