java/com/google/gerrit/server/logging/MutableAclLogRecords.java

// Copyright (C) 2020 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.logging;

import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.List;

/**
 * Thread-safe store for ACL log records.
 *
 * <p>This class is intended to keep track of user ACL records in {@link LoggingContext}. It needs
 * to be thread-safe because it gets shared between threads when the logging context is copied to
 * another thread (see {@link LoggingContextAwareRunnable} and {@link LoggingContextAwareCallable}.
 * In this case the logging contexts of both threads share the same instance of this class. This is
 * important since ACL log records are processed only at the end of a request and user ACL records
 * that are created in another thread should not get lost.
 */
public class MutableAclLogRecords {
  private final ArrayList<String> aclLogRecords = new ArrayList<>();

  public synchronized void add(String record) {
    aclLogRecords.add(record);
  }

  public synchronized void set(List<String> records) {
    aclLogRecords.clear();
    aclLogRecords.addAll(records);
  }

  public synchronized ImmutableList<String> list() {
    return ImmutableList.copyOf(aclLogRecords);
  }

  public boolean isEmpty() {
    return aclLogRecords.isEmpty();
  }

  @Override
  public String toString() {
    return MoreObjects.toStringHelper(this).add("aclLogRecords", aclLogRecords).toString();
  }
}