/* 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.activiti.engine.impl.cmd;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.Serializable;

import org.activiti.engine.impl.db.DbSqlSession;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.AttachmentEntity;
import org.activiti.engine.impl.persistence.entity.ByteArrayEntity;

/**
 * @author Tom Baeyens
 */
public class GetAttachmentContentCmd implements Command<InputStream>, Serializable {

    private static final long serialVersionUID = 1L;
    protected String attachmentId;

    public GetAttachmentContentCmd(String attachmentId) {
        this.attachmentId = attachmentId;
    }

    @Override
    public InputStream execute(CommandContext commandContext) {
        DbSqlSession dbSqlSession = commandContext.getDbSqlSession();
        AttachmentEntity attachment = dbSqlSession.selectById(AttachmentEntity.class, attachmentId);

        String contentId = attachment.getContentId();
        if (contentId == null) {
            return null;
        }

        ByteArrayEntity byteArray = dbSqlSession.selectById(ByteArrayEntity.class, contentId);
        byte[] bytes = byteArray.getBytes();

        return new ByteArrayInputStream(bytes);
    }

}
