com.mongodb.gridfs.GridFS 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 com.mongodb.gridfs;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoException;
import com.mongodb.lang.Nullable;
import org.bson.types.ObjectId;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* Implementation of GridFS - a specification for storing and retrieving files that exceed the BSON-document size limit of 16MB.
*
* Instead of storing a file in a single document, GridFS divides a file into parts, or chunks, and stores each of those chunks as a
* separate document. By default GridFS limits chunk size to 255k. GridFS uses two collections to store files. One collection stores the
* file chunks, and the other stores file metadata.
*
* When you query a GridFS store for a file, the driver or client will reassemble the chunks as needed. You can perform range queries on
* files stored through GridFS. You also can access information from arbitrary sections of files, which allows you to "skip" into the middle
* of a video or audio file.
*
* GridFS is useful not only for storing files that exceed 16MB but also for storing any files for which you want access without having
* to load the entire file into memory. For more information on the indications of GridFS, see MongoDB official documentation.
*
* @mongodb.driver.manual core/gridfs/ GridFS
*/
public class GridFS {
/**
* File's chunk size
*/
public static final int DEFAULT_CHUNKSIZE = 255 * 1024;
/**
* Bucket to use for the collection namespaces
*/
public static final String DEFAULT_BUCKET = "fs";
private final DB database;
private final String bucketName;
private final DBCollection filesCollection;
private final DBCollection chunksCollection;
/**
* Creates a GridFS instance for the default bucket "fs" in the given database. Set the preferred WriteConcern on the give DB with
* DB.setWriteConcern
*
* @param db database to work with
* @throws com.mongodb.MongoException if there's a failure
* @see com.mongodb.WriteConcern
*/
public GridFS(final DB db) {
this(db, DEFAULT_BUCKET);
}
/**
* Creates a GridFS instance for the specified bucket in the given database. Set the preferred WriteConcern on the give DB with
* DB.setWriteConcern
*
* @param db database to work with
* @param bucket bucket to use in the given database
* @throws com.mongodb.MongoException if there's a failure
* @see com.mongodb.WriteConcern
*/
public GridFS(final DB db, final String bucket) {
this.database = db;
this.bucketName = bucket;
this.filesCollection = database.getCollection(bucketName + ".files");
this.chunksCollection = database.getCollection(bucketName + ".chunks");
// ensure standard indexes as long as collections are small
try {
if (filesCollection.count() < 1000) {
filesCollection.createIndex(new BasicDBObject("filename", 1).append("uploadDate", 1));
}
if (chunksCollection.count() < 1000) {
chunksCollection.createIndex(new BasicDBObject("files_id", 1).append("n", 1),
new BasicDBObject("unique", true));
}
} catch (MongoException e) {
//TODO: Logging
}
filesCollection.setObjectClass(GridFSDBFile.class);
}
/**
* Gets the list of files stored in this gridfs, sorted by filename.
*
* @return cursor of file objects
*/
public DBCursor getFileList() {
return filesCollection.find().sort(new BasicDBObject("filename", 1));
}
/**
* Gets a filtered list of files stored in this gridfs, sorted by filename.
*
* @param query filter to apply
* @return cursor of file objects
*/
public DBCursor getFileList(final DBObject query) {
return filesCollection.find(query).sort(new BasicDBObject("filename", 1));
}
/**
* Gets a sorted, filtered list of files stored in this gridfs.
*
* @param query filter to apply
* @param sort sorting to apply
* @return cursor of file objects
*/
public DBCursor getFileList(final DBObject query, final DBObject sort) {
return filesCollection.find(query).sort(sort);
}
/**
* Finds one file matching the given objectId. Equivalent to findOne(objectId).
*
* @param objectId the objectId of the file stored on a server
* @return a gridfs file
* @throws com.mongodb.MongoException if the operation fails
*/
@Nullable
public GridFSDBFile find(final ObjectId objectId) {
return findOne(objectId);
}
/**
* Finds one file matching the given objectId.
*
* @param objectId the objectId of the file stored on a server
* @return a gridfs file
* @throws com.mongodb.MongoException if the operation fails
*/
@Nullable
public GridFSDBFile findOne(final ObjectId objectId) {
return findOne(new BasicDBObject("_id", objectId));
}
/**
* Finds one file matching the given filename.
*
* @param filename the name of the file stored on a server
* @return the gridfs db file
* @throws com.mongodb.MongoException if the operation fails
*/
@Nullable
public GridFSDBFile findOne(final String filename) {
return findOne(new BasicDBObject("filename", filename));
}
/**
* Finds one file matching the given query.
*
* @param query filter to apply
* @return a gridfs file
* @throws com.mongodb.MongoException if the operation fails
*/
@Nullable
public GridFSDBFile findOne(final DBObject query) {
return injectGridFSInstance(filesCollection.findOne(query));
}
/**
* Finds a list of files matching the given filename.
*
* @param filename the filename to look for
* @return list of gridfs files
* @throws com.mongodb.MongoException if the operation fails
*/
public List find(final String filename) {
return find(new BasicDBObject("filename", filename));
}
/**
* Finds a list of files matching the given filename.
*
* @param filename the filename to look for
* @param sort the fields to sort with
* @return list of gridfs files
* @throws com.mongodb.MongoException if the operation fails
*/
public List find(final String filename, final DBObject sort) {
return find(new BasicDBObject("filename", filename), sort);
}
/**
* Finds a list of files matching the given query.
*
* @param query the filter to apply
* @return list of gridfs files
* @throws com.mongodb.MongoException if the operation fails
*/
public List find(final DBObject query) {
return find(query, null);
}
/**
* Finds a list of files matching the given query.
*
* @param query the filter to apply
* @param sort the fields to sort with
* @return list of gridfs files
* @throws com.mongodb.MongoException if the operation fails
*/
public List find(final DBObject query, @Nullable final DBObject sort) {
List files = new ArrayList<>();
DBCursor cursor = filesCollection.find(query);
if (sort != null) {
cursor.sort(sort);
}
try {
while (cursor.hasNext()) {
files.add(injectGridFSInstance(cursor.next()));
}
} finally {
cursor.close();
}
return Collections.unmodifiableList(files);
}
@Nullable
private GridFSDBFile injectGridFSInstance(@Nullable final Object o) {
if (o == null) {
return null;
}
if (!(o instanceof GridFSDBFile)) {
throw new IllegalArgumentException("somehow didn't get a GridFSDBFile");
}
GridFSDBFile f = (GridFSDBFile) o;
f.fs = this;
return f;
}
/**
* Removes the file matching the given id.
*
* @param id the id of the file to be removed
* @throws com.mongodb.MongoException if the operation fails
*/
public void remove(final ObjectId id) {
if (id == null) {
throw new IllegalArgumentException("file id can not be null");
}
filesCollection.remove(new BasicDBObject("_id", id));
chunksCollection.remove(new BasicDBObject("files_id", id));
}
/**
* Removes all files matching the given filename.
*
* @param filename the name of the file to be removed
* @throws com.mongodb.MongoException if the operation fails
*/
public void remove(final String filename) {
if (filename == null) {
throw new IllegalArgumentException("filename can not be null");
}
remove(new BasicDBObject("filename", filename));
}
/**
* Removes all files matching the given query.
*
* @param query filter to apply
* @throws com.mongodb.MongoException if the operation fails
*/
public void remove(final DBObject query) {
if (query == null) {
throw new IllegalArgumentException("query can not be null");
}
for (final GridFSDBFile f : find(query)) {
f.remove();
}
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param data the file's data
* @return a gridfs input file
*/
public GridFSInputFile createFile(final byte[] data) {
return createFile(new ByteArrayInputStream(data), true);
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param file the file object
* @return a GridFS input file
* @throws IOException if there are problems reading {@code file}
*/
public GridFSInputFile createFile(final File file) throws IOException {
return createFile(new FileInputStream(file), file.getName(), true);
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param in an inputstream containing the file's data
* @return a gridfs input file
*/
public GridFSInputFile createFile(final InputStream in) {
return createFile(in, null);
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param in an inputstream containing the file's data
* @param closeStreamOnPersist indicate the passed in input stream should be closed once the data chunk persisted
* @return a gridfs input file
*/
public GridFSInputFile createFile(final InputStream in, final boolean closeStreamOnPersist) {
return createFile(in, null, closeStreamOnPersist);
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param in an inputstream containing the file's data
* @param filename the file name as stored in the db
* @return a gridfs input file
*/
public GridFSInputFile createFile(final InputStream in, @Nullable final String filename) {
return new GridFSInputFile(this, in, filename);
}
/**
* Creates a file entry. After calling this method, you have to call {@link com.mongodb.gridfs.GridFSInputFile#save()}.
*
* @param in an inputstream containing the file's data
* @param filename the file name as stored in the db
* @param closeStreamOnPersist indicate the passed in input stream should be closed once the data chunk persisted
* @return a gridfs input file
*/
public GridFSInputFile createFile(final InputStream in, @Nullable final String filename, final boolean closeStreamOnPersist) {
return new GridFSInputFile(this, in, filename, closeStreamOnPersist);
}
/**
* Creates a file entry.
*
* @param filename the file name as stored in the db
* @return a gridfs input file
* @see GridFS#createFile()
*/
public GridFSInputFile createFile(final String filename) {
return new GridFSInputFile(this, filename);
}
/**
* This method creates an empty {@link GridFSInputFile} instance. On this instance an {@link java.io.OutputStream} can be obtained using
* the {@link GridFSInputFile#getOutputStream()} method. You can still call {@link GridFSInputFile#setContentType(String)} and {@link
* GridFSInputFile#setFilename(String)}. The file will be completely written and closed after calling the {@link
* java.io.OutputStream#close()} method on the output stream.
*
* @return GridFS file handle instance.
*/
public GridFSInputFile createFile() {
return new GridFSInputFile(this);
}
/**
* Gets the bucket name used in the collection's namespace. Default value is 'fs'.
*
* @return the name of the file bucket
*/
public String getBucketName() {
return bucketName;
}
/**
* Gets the database used.
*
* @return the database
*/
public DB getDB() {
return database;
}
/**
* Gets the {@link DBCollection} in which the file's metadata is stored.
*
* @return the collection
*/
protected DBCollection getFilesCollection() {
return filesCollection;
}
/**
* Gets the {@link DBCollection} in which the binary chunks are stored.
*
* @return the collection
*/
protected DBCollection getChunksCollection() {
return chunksCollection;
}
}
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