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      1 /*
      2  * Copyright (C) 2007 The Guava Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.common.io;
     18 
     19 import static com.google.common.base.Preconditions.checkNotNull;
     20 
     21 import java.io.FilterInputStream;
     22 import java.io.IOException;
     23 import java.io.InputStream;
     24 import java.util.Random;
     25 
     26 /** Returns a random portion of the requested bytes on each call. */
     27 class RandomAmountInputStream extends FilterInputStream {
     28   private final Random random;
     29 
     30   public RandomAmountInputStream(InputStream in, Random random) {
     31     super(checkNotNull(in));
     32     this.random = checkNotNull(random);
     33   }
     34 
     35   @Override public int read(byte[] b, int off, int len) throws IOException {
     36     return super.read(b, off, random.nextInt(len) + 1);
     37   }
     38 }
     39