/*
* Copyright 2017 LinkedIn Corp.
*
* 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.linkedin.azkaban.spi;
import java.io.InputStream;
import java.net.URI;
/**
* The Azkaban Storage interface would facilitate getting and putting objects into a storage mechanism of choice.
* By default, this is set to the MySQL database. However, users can have the ability to choose between multiple
* storage types in future.
*
* This is different from storing Azkaban state in MySQL which would typically be maintained in a different database.
*
* Note: This is a synchronous interface.
*/
public interface Storage {
/**
* Check if key exists in storage.
*
* @param key The key is a URI pointing to the blob in Storage.
* @return true if key exists. false otherwise.
*/
boolean containsKey(URI key);
/**
* Get an InputStream object by providing a key. Throws {@link KeyDoesNotExistException} if key is not present.
*
* @param key The key is a URI pointing to the blob in Storage.
* @return InputStream for fetching the blob.
*
*/
InputStream get(URI key) throws KeyDoesNotExistException;
/**
* Put an object into Storage against a key. If the key already exists, then it throws
* {@link KeyAlreadyExistsException;}.
*
* @param key The key is a URI pointing to the blob in Storage.
* @param is The input stream from which the value is read to the store. The value is read completely
*/
void put(URI key, InputStream is) throws KeyAlreadyExistsException;
/**
* Delete an object from Storage. Throws {@link KeyDoesNotExistException} if key is not present.
*
* @param key The key is a URI pointing to the blob in Storage.
*/
void delete(URI key) throws KeyDoesNotExistException;
}