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Java example source code file (AsciiBenchmark.java)

This example Java source code file (AsciiBenchmark.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz, asciibenchmark, beforeexperiment, benchmark, charsequence, list, nonalpha, param, random, string, stringbuilder, util

The AsciiBenchmark.java Java example source code

/*
 * 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 com.google.common.base;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.common.base.Ascii;
import com.google.common.collect.Lists;
import com.google.common.primitives.Chars;

import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Random;

/**
 * Benchmarks for the ASCII class.
 *
 * @author Kevin Bourrillion
 */
public class AsciiBenchmark {
  private static String ALPHA =
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  private static String NONALPHA =
      "0123456789`~-_=+[]{}|;:',.<>/?!@#$%^&*()\"\\";

  @Param({"20", "2000"}) int size;
  @Param({"2", "20"}) int nonAlphaRatio; // one non-alpha char per this many chars
  @Param boolean noWorkToDo;

  Random random;
  String testString;

  @BeforeExperiment void setUp() {
    random = new Random();

    int nonAlpha = size / nonAlphaRatio;
    int alpha = size - nonAlpha;

    List<Character> chars = Lists.newArrayListWithCapacity(size);
    for (int i = 0; i < alpha; i++) {
      chars.add(randomAlpha());
    }
    for (int i = 0; i < nonAlpha; i++) {
      chars.add(randomNonAlpha());
    }
    Collections.shuffle(chars, random);
    char[] array = Chars.toArray(chars);
    this.testString = new String(array);
  }

  private char randomAlpha() {
    return ALPHA.charAt(random.nextInt(ALPHA.length()));
  }

  private char randomNonAlpha() {
    return NONALPHA.charAt(random.nextInt(NONALPHA.length()));
  }

  @Benchmark int asciiStringToUpperCase(int reps) {
    String string = noWorkToDo
        ? Ascii.toUpperCase(testString)
        : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += Ascii.toUpperCase(string).length();
    }
    return dummy;
  }

  @Benchmark int asciiCharSequenceToUpperCase(int reps) {
    String string = noWorkToDo
        ? charSequenceToUpperCase(testString)
        : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += charSequenceToUpperCase(string).length();
    }
    return dummy;
  }

  @Benchmark int stringToUpperCase(int reps) {
    String string = noWorkToDo
        ? testString.toUpperCase(Locale.US)
        : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += string.toUpperCase(Locale.US).length();
    }
    return dummy;
  }

  @Benchmark boolean equalsIgnoreCaseCharSequence(int reps) {
    // This benchmark has no concept of "noWorkToDo".
    String upperString = testString.toUpperCase();
    CharSequence testSeq = new StringBuilder(testString);
    CharSequence upperSeq = new StringBuilder(upperString);
    CharSequence[] lhs = new CharSequence[] { testString, testSeq, testString, testSeq };
    CharSequence[] rhs = new CharSequence[] { upperString, upperString, upperSeq, upperSeq };

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      dummy ^= Ascii.equalsIgnoreCase(lhs[i & 0x3], rhs[i & 0x3]);
    }
    return dummy;
  }

  @Benchmark boolean equalsIgnoreCaseStringOnly(int reps) {
    // This benchmark has no concept of "noWorkToDo".
    String lhs = testString;
    String rhs = testString.toUpperCase();

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      dummy ^= Ascii.equalsIgnoreCase(lhs, rhs);
    }
    return dummy;
  }

  @Benchmark boolean equalsIgnoreCaseJDK(int reps) {
    // This benchmark has no concept of "noWorkToDo".
    String lhs = testString;
    String rhs = testString.toUpperCase();

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
        dummy ^= lhs.equalsIgnoreCase(rhs);
    }
    return dummy;
  }

  @Benchmark boolean isUpperCase(int reps) {
    // This benchmark has no concept of "noWorkToDo".
    char[] chars = testString.toCharArray();

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      for (int n = 0; n < chars.length; n++) {
        dummy ^= Ascii.isUpperCase(chars[n]);
      }
    }
    return dummy;
  }

  static String charSequenceToUpperCase(CharSequence chars) {
    int length = chars.length();
    StringBuilder builder = new StringBuilder(length);
    for (int i = 0; i < length; i++) {
      builder.append(Ascii.toUpperCase(chars.charAt(i)));
    }
    return builder.toString();
  }
}

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