/*

  * 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.Iterator;

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

 import org.apache.giraph.function.Consumer;

 import org.apache.giraph.function.Supplier;

 import com.google.common.collect.AbstractIterator;

 import com.google.common.collect.Iterators;

 /**

  * Block that repeats another block until toQuit supplier returns true,

  * but at most given number of times.

  *

  * If toQuit returns true on first run, block is not going

  * to be executed at all.

  */

 @SuppressWarnings("rawtypes")

 public final class RepeatUntilBlock implements Block {

   private final Block block;

   private final int repeatTimes;

   private final Supplier<Boolean> toQuit;

   public RepeatUntilBlock(

       int repeatTimes, Block block, Supplier<Boolean> toQuit) {

     this.block = block;

     this.repeatTimes = repeatTimes;

     this.toQuit = toQuit;

   }

   /**

    * Repeat unlimited number of times, until toQuit supplier returns true.

    */

   public static Block unlimited(Block block, Supplier<Boolean> toQuit) {

     return new RepeatUntilBlock(Integer.MAX_VALUE, block, toQuit);

   }

   @Override

   public Iterator<AbstractPiece> iterator() {

     return Iterators.concat(new AbstractIterator<Iterator<AbstractPiece>>() {

       private int index = 0;

       @Override

       protected Iterator<AbstractPiece> computeNext() {

         if (index >= repeatTimes || Boolean.TRUE.equals(toQuit.get())) {

           return endOfData();

         }

         index++;

         return block.iterator();

       }

     });

   }

   @Override

   public void forAllPossiblePieces(Consumer<AbstractPiece> consumer) {

     block.forAllPossiblePieces(consumer);

   }

   @Override

   public PieceCount getPieceCount() {

     return PieceCount.createUnknownCount();

   }

   @Override

   public String toString() {

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

   }

 }