org.bson.BsonDocumentWrapper Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2015 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;
import org.bson.codecs.Encoder;
import org.bson.codecs.EncoderContext;
import org.bson.codecs.configuration.CodecRegistry;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
/**
* A {@code BsonDocument} that begins its life as a document of any type and an {@code Encoder} for that document, which lets an instance of
* any class with an Encoder be treated as a BsonDocument. If any methods are called which required access to the individual elements of the
* document, then, on demand, the document will be unwrapped into a BsonDocument using a {@code BsonDocumentWriter} and the {@code Encoder}.
* But if all that is done with this document is to encode it, then the {@code Encoder} will be used to do that.
*
* @param the type of the document that is wrapped
* @see org.bson.BsonDocumentWriter
* @since 3.0
*/
public final class BsonDocumentWrapper extends BsonDocument {
private static final long serialVersionUID = 1L;
private final transient T wrappedDocument;
private final transient Encoder encoder;
private BsonDocument unwrapped;
/**
* A helper to convert an document of type Object to a BsonDocument
*
* If not already a BsonDocument it looks up the documents' class in the codecRegistry and wraps it into a BsonDocumentWrapper
*
* @param document the document to convert
* @param codecRegistry the codecRegistry that can be used in the conversion of the Object
* @return a BsonDocument
*/
@SuppressWarnings({"rawtypes", "unchecked"})
public static BsonDocument asBsonDocument(final Object document, final CodecRegistry codecRegistry) {
if (document == null) {
return null;
}
if (document instanceof BsonDocument) {
return (BsonDocument) document;
} else {
return new BsonDocumentWrapper(document, codecRegistry.get(document.getClass()));
}
}
/**
* Construct a new instance with the given document and encoder for the document.
*
* @param wrappedDocument the wrapped document
* @param encoder the encoder for the wrapped document
*/
public BsonDocumentWrapper(final T wrappedDocument, final Encoder encoder) {
if (wrappedDocument == null) {
throw new IllegalArgumentException("Document can not be null");
}
this.wrappedDocument = wrappedDocument;
this.encoder = encoder;
}
/**
* Get the wrapped document.
*
* @return the wrapped document
*/
public T getWrappedDocument() {
return wrappedDocument;
}
/**
* Get the encoder to use for the wrapped document.
*
* @return the encoder
*/
public Encoder getEncoder() {
return encoder;
}
/**
* Determine whether the document has been unwrapped already.
*
* @return true if the wrapped document has been unwrapped already
*/
public boolean isUnwrapped() {
return unwrapped != null;
}
@Override
public int size() {
return getUnwrapped().size();
}
@Override
public boolean isEmpty() {
return getUnwrapped().isEmpty();
}
@Override
public boolean containsKey(final Object key) {
return getUnwrapped().containsKey(key);
}
@Override
public boolean containsValue(final Object value) {
return getUnwrapped().containsValue(value);
}
@Override
public BsonValue get(final Object key) {
return getUnwrapped().get(key);
}
@Override
public BsonValue put(final String key, final BsonValue value) {
return getUnwrapped().put(key, value);
}
@Override
public BsonValue remove(final Object key) {
return getUnwrapped().remove(key);
}
@Override
public void putAll(final Map m) {
super.putAll(m);
}
@Override
public void clear() {
super.clear();
}
@Override
public Set keySet() {
return getUnwrapped().keySet();
}
@Override
public Collection values() {
return getUnwrapped().values();
}
@Override
public Set> entrySet() {
return getUnwrapped().entrySet();
}
@Override
public boolean equals(final Object o) {
return getUnwrapped().equals(o);
}
@Override
public int hashCode() {
return getUnwrapped().hashCode();
}
@Override
public String toString() {
return getUnwrapped().toString();
}
@Override
public BsonDocument clone() {
return getUnwrapped().clone();
}
private BsonDocument getUnwrapped() {
if (encoder == null) {
throw new BsonInvalidOperationException("Can not unwrap a BsonDocumentWrapper with no Encoder");
}
if (unwrapped == null) {
BsonDocument unwrapped = new BsonDocument();
BsonWriter writer = new BsonDocumentWriter(unwrapped);
encoder.encode(writer, wrappedDocument, EncoderContext.builder().build());
this.unwrapped = unwrapped;
}
return unwrapped;
}
// see https://docs.oracle.com/javase/6/docs/platform/serialization/spec/output.html
private Object writeReplace() {
return getUnwrapped();
}
// see https://docs.oracle.com/javase/6/docs/platform/serialization/spec/input.html
private void readObject(final ObjectInputStream stream) throws InvalidObjectException {
throw new InvalidObjectException("Proxy required");
}
}