gerrit-server/src/main/java/com/google/gerrit/server/account/AccountInfoCacheFactory.java

// 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.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.gerrit.common.data.AccountInfo;
import com.google.gerrit.common.data.AccountInfoCache;
import com.google.gerrit.reviewdb.Account;
import com.google.gerrit.server.util.FutureUtil;
import com.google.inject.Inject;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Future;

/** Efficiently builds an {@link AccountInfoCache}. */
public class AccountInfoCacheFactory {
  public interface Factory {
    AccountInfoCacheFactory create();
  }

  private final AccountCache accountCache;
  private final Map<Account.Id, Future<Account>> want;

  @Inject
  AccountInfoCacheFactory(final AccountCache accountCache) {
    this.accountCache = accountCache;
    this.want = Maps.newHashMap();
  }

  /**
   * Indicate an account will be needed later on.
   *
   * @param id identity that will be needed in the future; may be null.
   */
  public void want(Account.Id id) {
    if (id != null && !want.containsKey(id)) {
      want.put(id, accountCache.getAccount(id));
    }
  }

  /** Indicate one or more accounts will be needed later on. */
  public void want(final Collection<Account.Id> ids) {
    for (Account.Id id : ids) {
      want(id);
    }
  }

  public Account get(final Account.Id id) {
    if (id != null) {
      want(id);
      return FutureUtil.get(want.get(id));
    } else {
      return null;
    }
  }

  /** Create an AccountInfoCache with the currently loaded Account entities. */
  public AccountInfoCache create() {
    List<AccountInfo> res = Lists.newArrayListWithCapacity(want.size());
    for (Future<Account> f : want.values()) {
      res.add(new AccountInfo(FutureUtil.get(f)));
    }
    return new AccountInfoCache(res);
  }
}