Merge branch 'masterEugen' into heapDump
This commit is contained in:
Marcos Lopez Gonzalez
@@ -145,3 +145,9 @@
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- [Common Java Exceptions](http://www.baeldung.com/java-common-exceptions)
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- [Java Constructors vs Static Factory Methods](https://www.baeldung.com/java-constructors-vs-static-factory-methods)
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- [Differences Between Final, Finally and Finalize in Java](https://www.baeldung.com/java-final-finally-finalize)
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- [Static and Dynamic Binding in Java](https://www.baeldung.com/java-static-dynamic-binding)
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- [Java List Initialization in One Line](https://www.baeldung.com/java-init-list-one-line)
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- [Difference Between Throw and Throws in Java](https://www.baeldung.com/java-throw-throws)
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- [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
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- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
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- [Add a Character to a String at a Given Position](https://www.baeldung.com/java-add-character-to-string)
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@@ -0,0 +1,100 @@
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package com.baeldung.removingdecimals;
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import org.junit.Test;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.runner.Runner;
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import org.openjdk.jmh.runner.options.Options;
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import org.openjdk.jmh.runner.options.OptionsBuilder;
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import java.math.BigDecimal;
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import java.math.RoundingMode;
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import java.text.DecimalFormat;
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import java.text.NumberFormat;
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import java.util.concurrent.TimeUnit;
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/**
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* This benchmark compares some of the approaches to formatting a floating-point
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* value into a {@link String} while removing the decimal part.
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*
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* To run, simply run the {@link RemovingDecimalsManualTest#runBenchmarks()} test
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* at the end of this class.
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*
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* The benchmark takes about 15 minutes to run. Since it is using {@link Mode#Throughput},
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* higher numbers mean better performance.
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*/
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@BenchmarkMode(Mode.Throughput)
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@Warmup(iterations = 5)
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@Measurement(iterations = 20)
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@OutputTimeUnit(TimeUnit.MICROSECONDS)
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@State(Scope.Benchmark)
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public class RemovingDecimalsManualTest {
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@Param(value = {"345.56", "345345345.56", "345345345345345345.56"}) double doubleValue;
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NumberFormat nf;
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DecimalFormat df;
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@Setup
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public void readyFormatters() {
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nf = NumberFormat.getInstance();
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nf.setMaximumFractionDigits(0);
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df = new DecimalFormat("#,###");
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}
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@Benchmark
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public String whenCastToInt_thenValueIsTruncated() {
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return String.valueOf((int) doubleValue);
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}
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@Benchmark
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public String whenUsingStringFormat_thenValueIsRounded() {
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return String.format("%.0f", doubleValue);
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}
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@Benchmark
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public String whenUsingNumberFormat_thenValueIsRounded() {
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nf.setRoundingMode(RoundingMode.HALF_UP);
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return nf.format(doubleValue);
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}
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@Benchmark
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public String whenUsingNumberFormatWithFloor_thenValueIsTruncated() {
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nf.setRoundingMode(RoundingMode.FLOOR);
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return nf.format(doubleValue);
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}
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@Benchmark
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public String whenUsingDecimalFormat_thenValueIsRounded() {
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df.setRoundingMode(RoundingMode.HALF_UP);
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return df.format(doubleValue);
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}
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@Benchmark
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public String whenUsingDecimalFormatWithFloor_thenValueIsTruncated() {
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df.setRoundingMode(RoundingMode.FLOOR);
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return df.format(doubleValue);
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}
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@Benchmark
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public String whenUsingBigDecimalDoubleValue_thenValueIsTruncated() {
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BigDecimal big = new BigDecimal(doubleValue);
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big = big.setScale(0, RoundingMode.FLOOR);
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return big.toString();
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}
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@Benchmark
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public String whenUsingBigDecimalDoubleValueWithHalfUp_thenValueIsRounded() {
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BigDecimal big = new BigDecimal(doubleValue);
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big = big.setScale(0, RoundingMode.HALF_UP);
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return big.toString();
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}
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@Test
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public void runBenchmarks() throws Exception {
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Options options = new OptionsBuilder()
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.include(this.getClass().getSimpleName()).threads(1)
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.forks(1).shouldFailOnError(true).shouldDoGC(true)
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.jvmArgs("-server").build();
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new Runner(options).run();
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}
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}
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@@ -0,0 +1,95 @@
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package com.baeldung.removingdecimals;
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import org.junit.Test;
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import java.math.BigDecimal;
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import java.math.RoundingMode;
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import java.text.DecimalFormat;
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import java.text.NumberFormat;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertNotEquals;
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/**
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* Tests that demonstrate some different approaches for formatting a
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* floating-point value into a {@link String} while removing the decimal part.
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*/
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public class RemovingDecimalsUnitTest {
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private final double doubleValue = 345.56;
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@Test
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public void whenCastToInt_thenValueIsTruncated() {
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String truncated = String.valueOf((int) doubleValue);
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assertEquals("345", truncated);
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}
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@Test
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public void givenALargeDouble_whenCastToInt_thenValueIsNotTruncated() {
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double outOfIntRange = 6_000_000_000.56;
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String truncationAttempt = String.valueOf((int) outOfIntRange);
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assertNotEquals("6000000000", truncationAttempt);
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}
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@Test
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public void whenUsingStringFormat_thenValueIsRounded() {
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String rounded = String.format("%.0f", doubleValue);
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assertEquals("346", rounded);
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}
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@Test
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public void givenALargeDouble_whenUsingStringFormat_thenValueIsStillRounded() {
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double outOfIntRange = 6_000_000_000.56;
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String rounded = String.format("%.0f", outOfIntRange);
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assertEquals("6000000001", rounded);
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}
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@Test
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public void whenUsingNumberFormat_thenValueIsRounded() {
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NumberFormat nf = NumberFormat.getInstance();
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nf.setMaximumFractionDigits(0);
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nf.setRoundingMode(RoundingMode.HALF_UP);
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String rounded = nf.format(doubleValue);
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assertEquals("346", rounded);
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}
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@Test
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public void whenUsingNumberFormatWithFloor_thenValueIsTruncated() {
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NumberFormat nf = NumberFormat.getInstance();
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nf.setMaximumFractionDigits(0);
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nf.setRoundingMode(RoundingMode.FLOOR);
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String truncated = nf.format(doubleValue);
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assertEquals("345", truncated);
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}
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@Test
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public void whenUsingDecimalFormat_thenValueIsRounded() {
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DecimalFormat df = new DecimalFormat("#,###");
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df.setRoundingMode(RoundingMode.HALF_UP);
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String rounded = df.format(doubleValue);
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assertEquals("346", rounded);
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}
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@Test
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public void whenUsingDecimalFormatWithFloor_thenValueIsTruncated() {
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DecimalFormat df = new DecimalFormat("#,###");
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df.setRoundingMode(RoundingMode.FLOOR);
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String truncated = df.format(doubleValue);
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assertEquals("345", truncated);
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}
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@Test
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public void whenUsingBigDecimalDoubleValue_thenValueIsTruncated() {
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BigDecimal big = new BigDecimal(doubleValue);
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big = big.setScale(0, RoundingMode.FLOOR);
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String truncated = big.toString();
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assertEquals("345", truncated);
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}
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@Test
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public void whenUsingBigDecimalDoubleValueWithHalfUp_thenValueIsRounded() {
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BigDecimal big = new BigDecimal(doubleValue);
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big = big.setScale(0, RoundingMode.HALF_UP);
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String truncated = big.toString();
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assertEquals("346", truncated);
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}
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}
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