org.efaps.db.store.Resource Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of efaps-kernel Show documentation

eFaps is a framework used to map objects with or without attached files to a relational database and optional file systems (only for attaches files). Configurable access control can be provided down to object and attribute level depending on implementation and use case. Depending on requirements, events (like triggers) allow to implement business logic and to separate business logic from user interface. The framework includes integrations (e.g. webdav, full text search) and a web application as 'simple' configurable user interface. Some best practises, example web application modules (e.g. team work module) support administrators and implementers using this framework.

There is a newer version: 3.2.0

Show newest version

/*
 * Copyright 2003 - 2011 The eFaps Team
 *
 * 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.
 *
 * Revision:        $Rev: 6210 $
 * Last Changed:    $Date: 2011-02-18 16:02:56 -0500 (Fri, 18 Feb 2011) $
 * Last Changed By: $Author: [email protected] $
 */

package org.efaps.db.store;

import java.io.InputStream;
import java.io.OutputStream;
import java.util.Map;

import javax.transaction.xa.XAResource;

import org.apache.commons.vfs.impl.DefaultFileSystemManager;
import org.efaps.db.Instance;
import org.efaps.util.EFapsException;

/**
 * TODO comment!
 *
 * @author The eFaps Team
 * @version $Id: Resource.java 6210 2011-02-18 21:02:56Z [email protected] $
 */
public interface Resource
    extends XAResource
{
    /**
     * Store resource could implement the possibility to compress and uncompress
     * data while writing to and reading from files.
     */
    enum Compress
    {
        /** File should not be compressed.*/
        NONE,
        /** File should be compressed using zip.*/
        ZIP,
        /** File should  be compressed using gzip.*/
        GZIP
    };

    /**
     * Writes the file with the given input stream.
     *
     * @param _in       input stream
     * @param _size     size of the data to write (or negative if the size is
     *                  not known)
     * @return length of the file which is stored
     * @throws EFapsException if an error occurs
     */
    int write(InputStream _in, int _size) throws EFapsException;

    /**
     * Method to open the Resource.
     *
     * @throws EFapsException on error
     */
    void open() throws EFapsException;

    /**
     * Method to commit the Resource.
     *
     * @throws EFapsException on error
     */
    void commit() throws EFapsException;

    /**
     * @return if the Resource was opened.
     */
    boolean isOpened();

    /**
     * Method to open the Resource.
     *
     * @throws EFapsException on error
     */
    void abort() throws EFapsException;

    /**
     * The input stream with the attached content of the object returned.
     *
     * @return input stream with the content of the file
     * @throws EFapsException if an error occurs
     */
    InputStream read() throws EFapsException;

    /**
     * The output stream is written with the content of the file. From method
     * {@link #read()} the input stream is used and copied into the output
     * stream.
     *
     * @param _out    output stream where the file content must be written
     * @throws EFapsException if an error occurs
     */
    void read(final OutputStream _out) throws EFapsException;

    /**
     * Will delete the file.
     *
     * @throws EFapsException if an error occurs
     */
    void delete() throws EFapsException;

    /**
     * Method called to initialize this StoreResource.
     * @see org.efaps.db.store.Resource#initialize(org.efaps.db.Instance,
     *  java.util.Map, org.efaps.db.store.Resource.Compress)
     * @param _instance     Instance of the object this StoreResource is wanted
     *                      for
     * @param _properties   properties for this StoreResource
     * @param _compress     compress type for this StoreResource
     * @throws EFapsException on error
     */
    void initialize(final Instance _instance,
                    final Map _properties,
                    final Compress _compress)
        throws EFapsException;

    /**
     * Method to determine if the Resource is a Virtual File System and
     * therefore needs a FileSystemManager.
     *
     * @return true if it is a VFS, else false
     */
    boolean isVFS();

    /**
     * Method is used to set the FileSytemManager for a Virtual File System.
     *
     * @param _fileSytemManager DefaultFileSystemManager to set
     */
    void setFileSystemManager(final DefaultFileSystemManager _fileSytemManager);

    /**
     * @return DefaultFileSystemManager
     * @throws EFapsException on error
     */
    DefaultFileSystemManager evaluateFileSystemManager() throws EFapsException;
}