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java/src/game/future/ThreadFactoryBuilder.java

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+/*
+ * Copyright (C) 2010 The Guava Authors
+ *
+ * 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 game.future;
+
+import java.lang.Thread.UncaughtExceptionHandler;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * A ThreadFactory builder, providing any combination of these features:
+ * <ul>
+ * <li> whether threads should be marked as {@linkplain Thread#setDaemon daemon}
+ * threads
+ * <li> a {@linkplain ThreadFactoryBuilder#setNameFormat naming format}
+ * <li> a {@linkplain Thread#setPriority thread priority}
+ * <li> an {@linkplain Thread#setUncaughtExceptionHandler uncaught exception
+ * handler}
+ * <li> a {@linkplain ThreadFactory#newThread backing thread factory}
+ * </ul>
+ * <p>If no backing thread factory is provided, a default backing thread factory is
+ * used as if by calling {@code setThreadFactory(}{@link
+ * Executors#defaultThreadFactory()}{@code )}.
+ *
+ * @author Kurt Alfred Kluever
+ * @since 4.0
+ */
+public final class ThreadFactoryBuilder {
+  private String nameFormat = null;
+  private Boolean daemon = null;
+  private Integer priority = null;
+  private UncaughtExceptionHandler uncaughtExceptionHandler = null;
+  private ThreadFactory backingThreadFactory = null;
+
+  /**
+   * Creates a new {@link ThreadFactory} builder.
+   */
+  public ThreadFactoryBuilder() {}
+
+  /**
+   * Sets the naming format to use when naming threads ({@link Thread#setName})
+   * which are created with this ThreadFactory.
+   *
+   * @param nameFormat a {@link String#format(String, Object...)}-compatible
+   *     format String, to which a unique integer (0, 1, etc.) will be supplied
+   *     as the single parameter. This integer will be unique to the built
+   *     instance of the ThreadFactory and will be assigned sequentially. For
+   *     example, {@code "rpc-pool-%d"} will generate thread names like
+   *     {@code "rpc-pool-0"}, {@code "rpc-pool-1"}, {@code "rpc-pool-2"}, etc.
+   * @return this for the builder pattern
+   */
+  
+  public ThreadFactoryBuilder setNameFormat(String nameFormat) {
+    String.format(nameFormat, 0); // fail fast if the format is bad or null
+    this.nameFormat = nameFormat;
+    return this;
+  }
+
+  /**
+   * Sets daemon or not for new threads created with this ThreadFactory.
+   *
+   * @param daemon whether or not new Threads created with this ThreadFactory
+   *     will be daemon threads
+   * @return this for the builder pattern
+   */
+  public ThreadFactoryBuilder setDaemon(boolean daemon) {
+    this.daemon = daemon;
+    return this;
+  }
+
+  /**
+   * Sets the priority for new threads created with this ThreadFactory.
+   *
+   * @param priority the priority for new Threads created with this
+   *     ThreadFactory
+   * @return this for the builder pattern
+   */
+//  public ThreadFactoryBuilder setPriority(int priority) {
+    // Thread#setPriority() already checks for validity. These error messages
+    // are nicer though and will fail-fast.
+//    checkArgument(priority >= Thread.MIN_PRIORITY,
+//        "Thread priority (%s) must be >= %s", priority, Thread.MIN_PRIORITY);
+//    checkArgument(priority <= Thread.MAX_PRIORITY,
+//        "Thread priority (%s) must be <= %s", priority, Thread.MAX_PRIORITY);
+//    this.priority = priority;
+//    return this;
+//  }
+
+  /**
+   * Sets the {@link UncaughtExceptionHandler} for new threads created with this
+   * ThreadFactory.
+   *
+   * @param uncaughtExceptionHandler the uncaught exception handler for new
+   *     Threads created with this ThreadFactory
+   * @return this for the builder pattern
+   */
+//  public ThreadFactoryBuilder setUncaughtExceptionHandler(
+//      UncaughtExceptionHandler uncaughtExceptionHandler) {
+//    this.uncaughtExceptionHandler = checkNotNull(uncaughtExceptionHandler);
+//    return this;
+//  }
+
+  /**
+   * Sets the backing {@link ThreadFactory} for new threads created with this
+   * ThreadFactory. Threads will be created by invoking #newThread(Runnable) on
+   * this backing {@link ThreadFactory}.
+   *
+   * @param backingThreadFactory the backing {@link ThreadFactory} which will
+   *     be delegated to during thread creation.
+   * @return this for the builder pattern
+   *
+   * @see MoreExecutors
+   */
+//  public ThreadFactoryBuilder setThreadFactory(
+//      ThreadFactory backingThreadFactory) {
+//    this.backingThreadFactory = checkNotNull(backingThreadFactory);
+//    return this;
+//  }
+
+  /**
+   * Returns a new thread factory using the options supplied during the building
+   * process. After building, it is still possible to change the options used to
+   * build the ThreadFactory and/or build again. State is not shared amongst
+   * built instances.
+   *
+   * @return the fully constructed {@link ThreadFactory}
+   */
+  public ThreadFactory build() {
+    return build(this);
+  }
+
+  private static ThreadFactory build(ThreadFactoryBuilder builder) {
+    final String nameFormat = builder.nameFormat;
+    final Boolean daemon = builder.daemon;
+    final Integer priority = builder.priority;
+    final UncaughtExceptionHandler uncaughtExceptionHandler =
+        builder.uncaughtExceptionHandler;
+    final ThreadFactory backingThreadFactory =
+        (builder.backingThreadFactory != null)
+        ? builder.backingThreadFactory
+        : Executors.defaultThreadFactory();
+    final AtomicLong count = (nameFormat != null) ? new AtomicLong(0) : null;
+    return new ThreadFactory() {
+      @Override public Thread newThread(Runnable runnable) {
+        Thread thread = backingThreadFactory.newThread(runnable);
+        if (nameFormat != null) {
+          thread.setName(String.format(nameFormat, count.getAndIncrement()));
+        }
+        if (daemon != null) {
+          thread.setDaemon(daemon);
+        }
+        if (priority != null) {
+          thread.setPriority(priority);
+        }
+        if (uncaughtExceptionHandler != null) {
+          thread.setUncaughtExceptionHandler(uncaughtExceptionHandler);
+        }
+        return thread;
+      }
+    };
+  }
+}