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/*
* Copyright 2018 StreamSets 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.streamsets.pipeline.api;
import java.util.Set;
import java.util.regex.Pattern;
/**
* General store for various data used by SDC and its various components.
*
* This store does not interpret the data in any way and deals with them as a black box. Storing and retrieving them
* by various components. Agreeing on proper data format and schema is up to the writer and caller.
*
* The objects within the store are separated into namespaces - each namespace is independent of each other and can
* contain objects with the same id. All objects are versioned and the store can contain the same object with multiple
* versions. The store imposes structural requirements for namespace, object id and version - all those must comport to
* exposed format. However the semantics of the values is not imposed and is left to the caller. Content itself is
* not interpreted in any way.
*/
public interface BlobStore {
/**
* Validation pattern for namespace.
*/
public static Pattern VALID_NAMESPACE_PATTERN = Pattern.compile("[A-Za-z0-9_-]+");
/**
* Validation pattern for id.
*/
public static Pattern VALID_ID_PATTERN = Pattern.compile("[A-Za-z0-9_.:-]+");
/**
* Store a new object inside the blob store.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @param version Version of the object.
* @param content The actual content.
* @throws StageException
*/
public void store(String namespace, String id, long version, String content) throws StageException;
/**
* Return latest version for given object.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @return Latest version (usual integer comparison)
* @throws StageException
*/
public long latestVersion(String namespace, String id) throws StageException;
/**
* Validates if given object exists on at least one version.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @return If given object in given namespace exists
*/
public boolean exists(String namespace, String id);
/**
* Validates if given object exists on given version.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @param version Version of the object.
* @return If given object on given in given namespace exists
*/
public boolean exists(String namespace, String id, long version);
/**
* Return all versions associated with given object.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @return Set of all stored versions.
* @throws StageException
*/
public Set allVersions(String namespace, String id);
/**
* Retrieve given object.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @param version Version of the object.
* @return Object itself
* @throws StageException
*/
public String retrieve(String namespace, String id, long version) throws StageException;
/**
* Sub-interface to encapsulate tuple of content with it's version.
*/
public interface VersionedContent {
/**
* Version of the content.
*/
long version();
/**
* Actual content
*/
String content();
}
/**
* Convenience method to return latest version for given object.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @return Object itself
* @throws StageException
*/
public VersionedContent retrieveLatest(String namespace, String id) throws StageException;
/**
* Delete given object from the store.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @param version Version of the object.
* @throws StageException
*/
public void delete(String namespace, String id, long version) throws StageException;
/**
* Delete all versions of given object.
*
* @param namespace Namespace of the object.
* @param id Id of the object.
* @throws StageException
*/
public void deleteAllVersions(String namespace, String id) throws StageException;
}