* {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *
   * <p>If the cache loader associated with this cache is known not to throw checked exceptions,
   * then prefer {@link #getUnchecked} over this method.
   *
   * @throws ExecutionException if a checked exception was thrown while loading the value. ({@code

   * writer each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned writer is closed.
   *
   * @throws IOException if an I/O error occurs while opening the writer
   */
  public abstract Writer openStream() throws IOException;

  /**
   * Opens a new buffered {@link Writer} for writing to this sink. The returned stream is not

    @Test
    void testNoProblems() {
        ToolchainsBuildingException e = new ToolchainsBuildingException(Collections.emptyList());
        assertEquals("0 problems were encountered while building the effective toolchains" + LS, e.getMessage());
    }

    @Test
    void testOneProblem() {
        ProblemCollector problemCollector = ProblemCollectorFactory.newInstance(null);

        return;
      } catch (InterruptedException ie) {
        throw new RuntimeException("Unexpected interrupt while waiting for future", ie);
      } catch (TimeoutException tryHarder) {
        /* OK */
      }
    } while (System.nanoTime() - deadline < 0);
    throw formatRuntimeException("Future not done within %d second timeout", timeoutSeconds);
  }

  /**

        while (properties.hasNext()) {
            final Map.Entry property = (Map.Entry) properties.next();
            final String key = (String) property.getKey();
            final StringBuilder value = new StringBuilder();
            final Iterator values = ((List) property.getValue()).iterator();
            while (values.hasNext()) {
                value.append(values.next());

   * it does.
   *
   * @throws IOException if an I/O error occurs while reading from this source
   */
  public ImmutableList<String> readLines() throws IOException {
    Closer closer = Closer.create();
    try {
      BufferedReader reader = closer.register(openBufferedStream());
      List<String> result = new ArrayList<>();
      String line;
      while ((line = reader.readLine()) != null) {
        result.add(line);

        return;
      } catch (InterruptedException ie) {
        throw new RuntimeException("Unexpected interrupt while waiting for future", ie);
      } catch (TimeoutException tryHarder) {
        /* OK */
      }
    } while (System.nanoTime() - deadline < 0);
    throw formatRuntimeException("Future not done within %d second timeout", timeoutSeconds);
  }

  /**

  public long addAndGet(K key, long delta) {
    outer:
    while (true) {
      AtomicLong atomic = map.get(key);
      if (atomic == null) {
        atomic = map.putIfAbsent(key, new AtomicLong(delta));
        if (atomic == null) {
          return delta;
        }
        // atomic is now non-null; fall through
      }

      while (true) {
        long oldValue = atomic.get();

   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *
   * <p>If the cache loader associated with this cache is known not to throw checked exceptions,
   * then prefer {@link #getUnchecked} over this method.
   *
   * @throws ExecutionException if a checked exception was thrown while loading the value. ({@code

    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

    // Lock while we check state. We must maintain the lock while adding the new pair so that
    // another thread can't run the list out from under us. We only add to the list if we have not
    // yet started execution.
    synchronized (lock) {
      if (!executed) {