/*
* Copyright (c) 2008-2014 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.DecoderContext;
import org.bson.codecs.UuidCodec;
import org.bson.io.ByteBufferBsonInput;
import org.bson.types.BSONTimestamp;
import org.bson.types.Binary;
import org.bson.types.Code;
import org.bson.types.CodeWScope;
import org.bson.types.MaxKey;
import org.bson.types.MinKey;
import org.bson.types.Symbol;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.Channels;
import java.nio.channels.WritableByteChannel;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;
import static org.bson.BsonBinarySubType.BINARY;
import static org.bson.BsonBinarySubType.OLD_BINARY;
/**
* An immutable {@code BSONObject} backed by a byte buffer that lazily provides keys and values on request. This is useful for transferring
* BSON documents between servers when you don't want to pay the performance penalty of encoding or decoding them fully.
*/
public class LazyBSONObject implements BSONObject {
private final byte[] bytes;
private final int offset;
private final LazyBSONCallback callback;
/**
* Construct an instance.
*
* @param bytes the raw bytes
* @param callback the callback to use to construct nested values
*/
public LazyBSONObject(final byte[] bytes, final LazyBSONCallback callback) {
this(bytes, 0, callback);
}
/**
* Construct an instance.
*
* @param bytes the raw bytes
* @param offset the offset into the raw bytes representing the start of the document
* @param callback the callback to use to construct nested values
*/
public LazyBSONObject(final byte[] bytes, final int offset, final LazyBSONCallback callback) {
this.bytes = bytes;
this.callback = callback;
this.offset = offset;
}
/**
* Gets the offset into the raw bytes representing the start of the document
*
* @return the offset
*/
protected int getOffset() {
return offset;
}
/**
* Gets the raw bytes.
*
* @return the raw bytes
*/
protected byte[] getBytes() {
return bytes;
}
@Override
public Object get(final String key) {
BsonBinaryReader reader = getBsonReader();
Object value;
try {
reader.readStartDocument();
value = null;
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
if (key.equals(reader.readName())) {
value = readValue(reader);
break;
} else {
reader.skipValue();
}
}
} finally {
reader.close();
}
return value;
}
@Override
@Deprecated
public boolean containsKey(final String key) {
return containsField(key);
}
@Override
public boolean containsField(final String s) {
BsonBinaryReader reader = getBsonReader();
try {
reader.readStartDocument();
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
if (reader.readName().equals(s)) {
return true;
} else {
reader.skipValue();
}
}
} finally {
reader.close();
}
return false;
}
@Override
public Set<String> keySet() {
Set<String> keys = new LinkedHashSet<String>();
BsonBinaryReader reader = getBsonReader();
try {
reader.readStartDocument();
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
keys.add(reader.readName());
reader.skipValue();
}
reader.readEndDocument();
} finally {
reader.close();
}
return Collections.unmodifiableSet(keys);
}
Object readValue(final BsonBinaryReader reader) {
switch (reader.getCurrentBsonType()) {
case DOCUMENT:
return readDocument(reader);
case ARRAY:
return readArray(reader);
case DOUBLE:
return reader.readDouble();
case STRING:
return reader.readString();
case BINARY:
byte binarySubType = reader.peekBinarySubType();
if (BsonBinarySubType.isUuid(binarySubType) && reader.peekBinarySize() == 16) {
return new UuidCodec().decode(reader, DecoderContext.builder().build());
}
BsonBinary binary = reader.readBinaryData();
if (binarySubType == BINARY.getValue() || binarySubType == OLD_BINARY.getValue()) {
return binary.getData();
} else {
return new Binary(binary.getType(), binary.getData());
}
case NULL:
reader.readNull();
return null;
case UNDEFINED:
reader.readUndefined();
return null;
case OBJECT_ID:
return reader.readObjectId();
case BOOLEAN:
return reader.readBoolean();
case DATE_TIME:
return new Date(reader.readDateTime());
case REGULAR_EXPRESSION:
BsonRegularExpression regularExpression = reader.readRegularExpression();
return Pattern.compile(
regularExpression.getPattern(),
BSON.regexFlags(regularExpression.getOptions())
);
case DB_POINTER:
BsonDbPointer dbPointer = reader.readDBPointer();
return callback.createDBRef(dbPointer.getNamespace(), dbPointer.getId());
case JAVASCRIPT:
return new Code(reader.readJavaScript());
case SYMBOL:
return new Symbol(reader.readSymbol());
case JAVASCRIPT_WITH_SCOPE:
return new CodeWScope(reader.readJavaScriptWithScope(), (BSONObject) readJavaScriptWithScopeDocument(reader));
case INT32:
return reader.readInt32();
case TIMESTAMP:
BsonTimestamp timestamp = reader.readTimestamp();
return new BSONTimestamp(timestamp.getTime(), timestamp.getInc());
case INT64:
return reader.readInt64();
case DECIMAL128:
return reader.readDecimal128();
case MIN_KEY:
reader.readMinKey();
return new MinKey();
case MAX_KEY:
reader.readMaxKey();
return new MaxKey();
default:
throw new IllegalArgumentException("unhandled BSON type: " + reader.getCurrentBsonType());
}
}
private Object readArray(final BsonBinaryReader reader) {
int position = reader.getBsonInput().getPosition();
reader.skipValue();
return callback.createArray(bytes, offset + position);
}
private Object readDocument(final BsonBinaryReader reader) {
int position = reader.getBsonInput().getPosition();
reader.skipValue();
return callback.createObject(bytes, offset + position);
}
private Object readJavaScriptWithScopeDocument(final BsonBinaryReader reader) {
int position = reader.getBsonInput().getPosition();
reader.readStartDocument();
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
reader.skipName();
reader.skipValue();
}
reader.readEndDocument();
return callback.createObject(bytes, offset + position);
}
BsonBinaryReader getBsonReader() {
ByteBuffer buffer = getBufferForInternalBytes();
return new BsonBinaryReader(new ByteBufferBsonInput(new ByteBufNIO(buffer)));
}
private ByteBuffer getBufferForInternalBytes() {
ByteBuffer buffer = ByteBuffer.wrap(bytes, offset, bytes.length - offset).slice();
buffer.order(ByteOrder.LITTLE_ENDIAN);
buffer.limit(buffer.getInt());
buffer.rewind();
return buffer;
}
/**
* Gets whether this is an empty {@code BSONObject}.
*
* @return true if this has no keys
*/
public boolean isEmpty() {
return keySet().size() == 0;
}
/**
* Gets the size in bytes of the BSON document.
*
* @return the size in bytes
*/
public int getBSONSize() {
return getBufferForInternalBytes().getInt();
}
/**
* Pipe the raw bytes into the given output stream.
*
* @param os the output stream
* @return the number of bytes written
* @throws IOException any IOException thrown by the output stream
*/
public int pipe(final OutputStream os) throws IOException {
WritableByteChannel channel = Channels.newChannel(os);
return channel.write(getBufferForInternalBytes());
}
/**
* Gets the entry set for all the key/value pairs in this {@code BSONObject}. The returned set is immutable.
*
* @return then entry set
*/
public Set<Map.Entry<String, Object>> entrySet() {
final List<Map.Entry<String, Object>> entries = new ArrayList<Map.Entry<String, Object>>();
BsonBinaryReader reader = getBsonReader();
try {
reader.readStartDocument();
while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
entries.add(new AbstractMap.SimpleImmutableEntry<String, Object>(reader.readName(), readValue(reader)));
}
reader.readEndDocument();
} finally {
reader.close();
}
return new Set<Map.Entry<String, Object>>() {
@Override
public int size() {
return entries.size();
}
@Override
public boolean isEmpty() {
return entries.isEmpty();
}
@Override
public Iterator<Map.Entry<String, Object>> iterator() {
return entries.iterator();
}
@Override
public Object[] toArray() {
return entries.toArray();
}
@Override
public <T> T[] toArray(final T[] a) {
return entries.toArray(a);
}
@Override
public boolean contains(final Object o) {
return entries.contains(o);
}
@Override
public boolean containsAll(final Collection<?> c) {
return entries.containsAll(c);
}
@Override
public boolean add(final Map.Entry<String, Object> stringObjectEntry) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(final Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(final Collection<? extends Map.Entry<String, Object>> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(final Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(final Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
};
}
@Override
public int hashCode() {
int result = 1;
int size = getBSONSize();
for (int i = offset; i < offset + size; i++) {
result = 31 * result + bytes[i];
}
return result;
}
@Override
public boolean equals(final Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
LazyBSONObject other = (LazyBSONObject) o;
if (this.bytes == other.bytes && this.offset == other.offset) {
return true;
}
if (this.bytes == null || other.bytes == null) {
return false;
}
if (this.bytes.length == 0 || other.bytes.length == 0) {
return false;
}
//comparing document length
int length = this.bytes[this.offset];
if (other.bytes[other.offset] != length) {
return false;
}
//comparing document contents
for (int i = 0; i < length; i++) {
if (this.bytes[this.offset + i] != other.bytes[other.offset + i]) {
return false;
}
}
return true;
}
/**
* Returns a JSON serialization of this object
*
* @return JSON serialization
*/
@SuppressWarnings("deprecation")
public String toString() {
return com.mongodb.util.JSON.serialize(this);
}
/* ----------------- Unsupported operations --------------------- */
/**
* Always throws {@code UnsupportedOperationException}.
*
* @param key Name to set
* @param v Corresponding value
* @return will not return normally
* @throws java.lang.UnsupportedOperationException the object is read only
*/
@Override
public Object put(final String key, final Object v) {
throw new UnsupportedOperationException("Object is read only");
}
/**
* Always throws {@code UnsupportedOperationException}.
*
* @param o the object
* @throws java.lang.UnsupportedOperationException the object is read only
*/
@Override
public void putAll(final BSONObject o) {
throw new UnsupportedOperationException("Object is read only");
}
/**
* Always throws {@code UnsupportedOperationException}.
*
* @param m the map
* @throws java.lang.UnsupportedOperationException the object is read only
*/@Override
@SuppressWarnings("rawtypes")
public void putAll(final Map m) {
throw new UnsupportedOperationException("Object is read only");
}
/**
* Always throws {@code UnsupportedOperationException}.
*
* @param key The name of the field to remove
* @return will not return normally
* @throws java.lang.UnsupportedOperationException the object is read only
*/
@Override
public Object removeField(final String key) {
throw new UnsupportedOperationException("Object is read only");
}
@Override
@SuppressWarnings("rawtypes")
public Map toMap() {
Map<String, Object> map = new LinkedHashMap<String, Object>();
for (final Map.Entry<String, Object> entry : entrySet()) {
map.put(entry.getKey(), entry.getValue());
}
return Collections.unmodifiableMap(map);
}
}