/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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 org.apache.giraph.block_app.framework.block;

 import java.util.Collections;

 import java.util.Iterator;

 import org.apache.giraph.block_app.framework.piece.AbstractPiece;

 import org.apache.giraph.function.Consumer;

 import org.apache.giraph.function.primitive.IntSupplier;

 import com.google.common.collect.Iterables;

 /**

  * Block that repeats another block given number of times.

  */

 @SuppressWarnings("rawtypes")

 public final class RepeatBlock implements Block {

   private final Block block;

   private final boolean constantRepeatTimes;

   private final IntSupplier repeatTimes;

   public RepeatBlock(final int repeatTimes, Block block) {

     this.block = block;

     this.constantRepeatTimes = true;

     this.repeatTimes = new IntSupplier() {

       @Override

       public int get() {

         return repeatTimes;

       }

     };

   }

   /**

    * Creates a repeat block, that before starting execution takes number of

    * iterations from the given supplier.

    *

    * This allows number of iterations to be dynamic, and depend on

    * execution that happens before.

    * Note - it doesn't allow for number of repetitions to change during the

    * loop itself - as it is supplier is called only when this block gets

    * its turn.

    */

   public RepeatBlock(IntSupplier repeatTimes, Block block) {

     this.block = block;

     this.constantRepeatTimes = false;

     this.repeatTimes = repeatTimes;

   }

   /**

    * Create a repeat block that executes unlimited number of times.

    *

    * Should rarely be used, as it will cause application never to finish,

    * unless other unconventional ways of termination are used.

    */

   public static Block unlimited(Block block) {

     return new RepeatBlock(Integer.MAX_VALUE, block);

   }

   @Override

   public Iterator<AbstractPiece> iterator() {

     return Iterables.concat(

         Collections.nCopies(repeatTimes.get(), block)).iterator();

   }

   @Override

   public void forAllPossiblePieces(Consumer<AbstractPiece> consumer) {

     block.forAllPossiblePieces(consumer);

   }

   @Override

   public PieceCount getPieceCount() {

     return constantRepeatTimes ?

         block.getPieceCount().multiply(repeatTimes.get()) :

         PieceCount.createUnknownCount();

   }

   @Override

   public String toString() {

     return "RepeatBlock(" + repeatTimes + " * " + block + ")";

   }

 }