com.google.gerrit.server.account.AccountCache Maven / Gradle / Ivy
// Copyright (C) 2009 The Android Open Source Project
//
// 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.google.gerrit.server.account;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.reviewdb.client.Account;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
/** Caches important (but small) account state to avoid database hits. */
public interface AccountCache {
/**
* Returns an {@code AccountState} instance for the given account ID. If not cached yet the
* account is loaded. Returns {@link Optional#empty()} if the account is missing.
*
* @param accountId ID of the account that should be retrieved
* @return {@code AccountState} instance for the given account ID, if no account with this ID
* exists {@link Optional#empty()} is returned
*/
Optional get(Account.Id accountId);
/**
* Returns a {@code Map} of {@code Account.Id} to {@code AccountState} for the given account IDs.
* If not cached yet the accounts are loaded. If an account can't be loaded (e.g. because it is
* missing), the entry will be missing from the result.
*
* Loads accounts in parallel if applicable.
*
* @param accountIds IDs of the account that should be retrieved
* @return {@code Map} of {@code Account.Id} to {@code AccountState} instances for the given
* account IDs, if an account can't be loaded (e.g. because it is missing), the entry will be
* missing from the result
*/
Map get(Set accountIds);
/**
* Returns an {@code AccountState} instance for the given account ID. If not cached yet the
* account is loaded. Returns an empty {@code AccountState} instance to represent a missing
* account.
*
* This method should only be used in exceptional cases where it is required to get an account
* state even if the account is missing. Callers should leave a comment with the method invocation
* explaining why this method is used. Most callers of {@link AccountCache} should use {@link
* #get(Account.Id)} instead and handle the missing account case explicitly.
*
* @param accountId ID of the account that should be retrieved
* @return {@code AccountState} instance for the given account ID, if no account with this ID
* exists an empty {@code AccountState} instance is returned to represent the missing account
*/
AccountState getEvenIfMissing(Account.Id accountId);
/**
* Returns an {@code AccountState} instance for the given username.
*
*
This method first loads the external ID for the username and then uses the account ID of the
* external ID to lookup the account from the cache.
*
* @param username username of the account that should be retrieved
* @return {@code AccountState} instance for the given username, if no account with this username
* exists or if loading the external ID fails {@link Optional#empty()} is returned
*/
Optional getByUsername(String username);
/**
* Evicts the account from the cache.
*
* @param accountId account ID of the account that should be evicted
*/
void evict(@Nullable Account.Id accountId);
/** Evict all accounts from the cache. */
void evictAll();
}