Coverage Report - org.apache.commons.lang3.concurrent.BasicThreadFactory
 
Classes in this File Line Coverage Branch Coverage Complexity
BasicThreadFactory
100%
30/30
100%
10/10
1,312
BasicThreadFactory$1
N/A
N/A
1,312
BasicThreadFactory$Builder
100%
23/23
N/A
1,312
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  *
 9  
  *      http://www.apache.org/licenses/LICENSE-2.0
 10  
  *
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.lang3.concurrent;
 18  
 
 19  
 import java.util.concurrent.Executors;
 20  
 import java.util.concurrent.ThreadFactory;
 21  
 import java.util.concurrent.atomic.AtomicLong;
 22  
 
 23  
 import org.apache.commons.lang3.Validate;
 24  
 
 25  
 /**
 26  
  * <p>
 27  
  * An implementation of the {@code ThreadFactory} interface that provides some
 28  
  * configuration options for the threads it creates.
 29  
  * </p>
 30  
  * <p>
 31  
  * A {@code ThreadFactory} is used for instance by an {@code ExecutorService} to
 32  
  * create the threads it uses for executing tasks. In many cases users do not
 33  
  * have to care about a {@code ThreadFactory} because the default one used by an
 34  
  * {@code ExecutorService} will do. However, if there are special requirements
 35  
  * for the threads, a custom {@code ThreadFactory} has to be created.
 36  
  * </p>
 37  
  * <p>
 38  
  * This class provides some frequently needed configuration options for the
 39  
  * threads it creates. These are the following:
 40  
  * </p>
 41  
  * <ul>
 42  
  * <li>A name pattern for the threads created by this factory can be specified.
 43  
  * This is often useful if an application uses multiple executor services for
 44  
  * different purposes. If the names of the threads used by these services have
 45  
  * meaningful names, log output or exception traces can be much easier to read.
 46  
  * Naming patterns are <em>format strings</em> as used by the {@code
 47  
  * String.format()} method. The string can contain the place holder {@code %d}
 48  
  * which will be replaced by the number of the current thread ({@code
 49  
  * ThreadFactoryImpl} keeps a counter of the threads it has already created).
 50  
  * For instance, the naming pattern {@code "My %d. worker thread"} will result
 51  
  * in thread names like {@code "My 1. worker thread"}, {@code
 52  
  * "My 2. worker thread"} and so on.</li>
 53  
  * <li>A flag whether the threads created by this factory should be daemon
 54  
  * threads. This can impact the exit behavior of the current Java application
 55  
  * because the JVM shuts down if there are only daemon threads running.</li>
 56  
  * <li>The priority of the thread. Here an integer value can be provided. The
 57  
  * {@code java.lang.Thread} class defines constants for valid ranges of priority
 58  
  * values.</li>
 59  
  * <li>The {@code UncaughtExceptionHandler} for the thread. This handler is
 60  
  * called if an uncaught exception occurs within the thread.</li>
 61  
  * </ul>
 62  
  * <p>
 63  
  * {@code BasicThreadFactory} wraps another thread factory which actually
 64  
  * creates new threads. The configuration options are set on the threads created
 65  
  * by the wrapped thread factory. On construction time the factory to be wrapped
 66  
  * can be specified. If none is provided, a default {@code ThreadFactory} is
 67  
  * used.
 68  
  * </p>
 69  
  * <p>
 70  
  * Instances of {@code BasicThreadFactory} are not created directly, but the
 71  
  * nested {@code Builder} class is used for this purpose. Using the builder only
 72  
  * the configuration options an application is interested in need to be set. The
 73  
  * following example shows how a {@code BasicThreadFactory} is created and
 74  
  * installed in an {@code ExecutorService}:
 75  
  * </p>
 76  
  *
 77  
  * <pre>
 78  
  * // Create a factory that produces daemon threads with a naming pattern and
 79  
  * // a priority
 80  
  * BasicThreadFactory factory = new BasicThreadFactory.Builder()
 81  
  *     .namingPattern(&quot;workerthread-%d&quot;)
 82  
  *     .daemon(true)
 83  
  *     .priority(Thread.MAX_PRIORITY)
 84  
  *     .build();
 85  
  * // Create an executor service for single-threaded execution
 86  
  * ExecutorService exec = Executors.newSingleThreadExecutor(factory);
 87  
  * </pre>
 88  
  *
 89  
  * @since 3.0
 90  
  */
 91  13
 public class BasicThreadFactory implements ThreadFactory {
 92  
     /** A counter for the threads created by this factory. */
 93  
     private final AtomicLong threadCounter;
 94  
 
 95  
     /** Stores the wrapped factory. */
 96  
     private final ThreadFactory wrappedFactory;
 97  
 
 98  
     /** Stores the uncaught exception handler. */
 99  
     private final Thread.UncaughtExceptionHandler uncaughtExceptionHandler;
 100  
 
 101  
     /** Stores the naming pattern for newly created threads. */
 102  
     private final String namingPattern;
 103  
 
 104  
     /** Stores the priority. */
 105  
     private final Integer priority;
 106  
 
 107  
     /** Stores the daemon status flag. */
 108  
     private final Boolean daemonFlag;
 109  
 
 110  
     /**
 111  
      * Creates a new instance of {@code ThreadFactoryImpl} and configures it
 112  
      * from the specified {@code Builder} object.
 113  
      *
 114  
      * @param builder the {@code Builder} object
 115  
      */
 116  13
     private BasicThreadFactory(final Builder builder) {
 117  13
         if (builder.wrappedFactory == null) {
 118  3
             wrappedFactory = Executors.defaultThreadFactory();
 119  
         } else {
 120  10
             wrappedFactory = builder.wrappedFactory;
 121  
         }
 122  
 
 123  13
         namingPattern = builder.namingPattern;
 124  13
         priority = builder.priority;
 125  13
         daemonFlag = builder.daemonFlag;
 126  13
         uncaughtExceptionHandler = builder.exceptionHandler;
 127  
 
 128  13
         threadCounter = new AtomicLong();
 129  13
     }
 130  
 
 131  
     /**
 132  
      * Returns the wrapped {@code ThreadFactory}. This factory is used for
 133  
      * actually creating threads. This method never returns <b>null</b>. If no
 134  
      * {@code ThreadFactory} was passed when this object was created, a default
 135  
      * thread factory is returned.
 136  
      *
 137  
      * @return the wrapped {@code ThreadFactory}
 138  
      */
 139  
     public final ThreadFactory getWrappedFactory() {
 140  25
         return wrappedFactory;
 141  
     }
 142  
 
 143  
     /**
 144  
      * Returns the naming pattern for naming newly created threads. Result can
 145  
      * be <b>null</b> if no naming pattern was provided.
 146  
      *
 147  
      * @return the naming pattern
 148  
      */
 149  
     public final String getNamingPattern() {
 150  36
         return namingPattern;
 151  
     }
 152  
 
 153  
     /**
 154  
      * Returns the daemon flag. This flag determines whether newly created
 155  
      * threads should be daemon threads. If <b>true</b>, this factory object
 156  
      * calls {@code setDaemon(true)} on the newly created threads. Result can be
 157  
      * <b>null</b> if no daemon flag was provided at creation time.
 158  
      *
 159  
      * @return the daemon flag
 160  
      */
 161  
     public final Boolean getDaemonFlag() {
 162  26
         return daemonFlag;
 163  
     }
 164  
 
 165  
     /**
 166  
      * Returns the priority of the threads created by this factory. Result can
 167  
      * be <b>null</b> if no priority was specified.
 168  
      *
 169  
      * @return the priority for newly created threads
 170  
      */
 171  
     public final Integer getPriority() {
 172  25
         return priority;
 173  
     }
 174  
 
 175  
     /**
 176  
      * Returns the {@code UncaughtExceptionHandler} for the threads created by
 177  
      * this factory. Result can be <b>null</b> if no handler was provided.
 178  
      *
 179  
      * @return the {@code UncaughtExceptionHandler}
 180  
      */
 181  
     public final Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
 182  25
         return uncaughtExceptionHandler;
 183  
     }
 184  
 
 185  
     /**
 186  
      * Returns the number of threads this factory has already created. This
 187  
      * class maintains an internal counter that is incremented each time the
 188  
      * {@link #newThread(Runnable)} method is invoked.
 189  
      *
 190  
      * @return the number of threads created by this factory
 191  
      */
 192  
     public long getThreadCount() {
 193  12
         return threadCounter.get();
 194  
     }
 195  
 
 196  
     /**
 197  
      * Creates a new thread. This implementation delegates to the wrapped
 198  
      * factory for creating the thread. Then, on the newly created thread the
 199  
      * corresponding configuration options are set.
 200  
      *
 201  
      * @param r the {@code Runnable} to be executed by the new thread
 202  
      * @return the newly created thread
 203  
      */
 204  
     @Override
 205  
     public Thread newThread(final Runnable r) {
 206  21
         final Thread t = getWrappedFactory().newThread(r);
 207  21
         initializeThread(t);
 208  
 
 209  21
         return t;
 210  
     }
 211  
 
 212  
     /**
 213  
      * Initializes the specified thread. This method is called by
 214  
      * {@link #newThread(Runnable)} after a new thread has been obtained from
 215  
      * the wrapped thread factory. It initializes the thread according to the
 216  
      * options set for this factory.
 217  
      *
 218  
      * @param t the thread to be initialized
 219  
      */
 220  
     private void initializeThread(final Thread t) {
 221  
 
 222  21
         if (getNamingPattern() != null) {
 223  12
             final Long count = Long.valueOf(threadCounter.incrementAndGet());
 224  12
             t.setName(String.format(getNamingPattern(), count));
 225  
         }
 226  
 
 227  21
         if (getUncaughtExceptionHandler() != null) {
 228  1
             t.setUncaughtExceptionHandler(getUncaughtExceptionHandler());
 229  
         }
 230  
 
 231  21
         if (getPriority() != null) {
 232  1
             t.setPriority(getPriority().intValue());
 233  
         }
 234  
 
 235  21
         if (getDaemonFlag() != null) {
 236  2
             t.setDaemon(getDaemonFlag().booleanValue());
 237  
         }
 238  21
     }
 239  
 
 240  
     /**
 241  
      * <p>
 242  
      * A <em>builder</em> class for creating instances of {@code
 243  
      * BasicThreadFactory}.
 244  
      * </p>
 245  
      * <p>
 246  
      * Using this builder class instances of {@code BasicThreadFactory} can be
 247  
      * created and initialized. The class provides methods that correspond to
 248  
      * the configuration options supported by {@code BasicThreadFactory}. Method
 249  
      * chaining is supported. Refer to the documentation of {@code
 250  
      * BasicThreadFactory} for a usage example.
 251  
      * </p>
 252  
      *
 253  
      */
 254  90
     public static class Builder
 255  
         implements org.apache.commons.lang3.builder.Builder<BasicThreadFactory> {
 256  
 
 257  
         /** The wrapped factory. */
 258  
         private ThreadFactory wrappedFactory;
 259  
 
 260  
         /** The uncaught exception handler. */
 261  
         private Thread.UncaughtExceptionHandler exceptionHandler;
 262  
 
 263  
         /** The naming pattern. */
 264  
         private String namingPattern;
 265  
 
 266  
         /** The priority. */
 267  
         private Integer priority;
 268  
 
 269  
         /** The daemon flag. */
 270  
         private Boolean daemonFlag;
 271  
 
 272  
         /**
 273  
          * Sets the {@code ThreadFactory} to be wrapped by the new {@code
 274  
          * BasicThreadFactory}.
 275  
          *
 276  
          * @param factory the wrapped {@code ThreadFactory} (must not be
 277  
          * <b>null</b>)
 278  
          * @return a reference to this {@code Builder}
 279  
          * @throws NullPointerException if the passed in {@code ThreadFactory}
 280  
          * is <b>null</b>
 281  
          */
 282  
         public Builder wrappedFactory(final ThreadFactory factory) {
 283  12
             Validate.notNull(factory, "Wrapped ThreadFactory must not be null!");
 284  
 
 285  11
             wrappedFactory = factory;
 286  11
             return this;
 287  
         }
 288  
 
 289  
         /**
 290  
          * Sets the naming pattern to be used by the new {@code
 291  
          * BasicThreadFactory}.
 292  
          *
 293  
          * @param pattern the naming pattern (must not be <b>null</b>)
 294  
          * @return a reference to this {@code Builder}
 295  
          * @throws NullPointerException if the naming pattern is <b>null</b>
 296  
          */
 297  
         public Builder namingPattern(final String pattern) {
 298  4
             Validate.notNull(pattern, "Naming pattern must not be null!");
 299  
 
 300  3
             namingPattern = pattern;
 301  3
             return this;
 302  
         }
 303  
 
 304  
         /**
 305  
          * Sets the daemon flag for the new {@code BasicThreadFactory}. If this
 306  
          * flag is set to <b>true</b> the new thread factory will create daemon
 307  
          * threads.
 308  
          *
 309  
          * @param f the value of the daemon flag
 310  
          * @return a reference to this {@code Builder}
 311  
          */
 312  
         public Builder daemon(final boolean f) {
 313  4
             daemonFlag = Boolean.valueOf(f);
 314  4
             return this;
 315  
         }
 316  
 
 317  
         /**
 318  
          * Sets the priority for the threads created by the new {@code
 319  
          * BasicThreadFactory}.
 320  
          *
 321  
          * @param prio the priority
 322  
          * @return a reference to this {@code Builder}
 323  
          */
 324  
         public Builder priority(final int prio) {
 325  2
             priority = Integer.valueOf(prio);
 326  2
             return this;
 327  
         }
 328  
 
 329  
         /**
 330  
          * Sets the uncaught exception handler for the threads created by the
 331  
          * new {@code BasicThreadFactory}.
 332  
          *
 333  
          * @param handler the {@code UncaughtExceptionHandler} (must not be
 334  
          * <b>null</b>)
 335  
          * @return a reference to this {@code Builder}
 336  
          * @throws NullPointerException if the exception handler is <b>null</b>
 337  
          */
 338  
         public Builder uncaughtExceptionHandler(
 339  
                 final Thread.UncaughtExceptionHandler handler) {
 340  3
             Validate.notNull(handler, "Uncaught exception handler must not be null!");
 341  
 
 342  2
             exceptionHandler = handler;
 343  2
             return this;
 344  
         }
 345  
 
 346  
         /**
 347  
          * Resets this builder. All configuration options are set to default
 348  
          * values. Note: If the {@link #build()} method was called, it is not
 349  
          * necessary to call {@code reset()} explicitly because this is done
 350  
          * automatically.
 351  
          */
 352  
         public void reset() {
 353  14
             wrappedFactory = null;
 354  14
             exceptionHandler = null;
 355  14
             namingPattern = null;
 356  14
             priority = null;
 357  14
             daemonFlag = null;
 358  14
         }
 359  
 
 360  
         /**
 361  
          * Creates a new {@code BasicThreadFactory} with all configuration
 362  
          * options that have been specified by calling methods on this builder.
 363  
          * After creating the factory {@link #reset()} is called.
 364  
          *
 365  
          * @return the new {@code BasicThreadFactory}
 366  
          */
 367  
         @Override
 368  
         public BasicThreadFactory build() {
 369  13
             final BasicThreadFactory factory = new BasicThreadFactory(this);
 370  13
             reset();
 371  13
             return factory;
 372  
         }
 373  
     }
 374  
 }