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Merge pull request #8358 from sampada07/master

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BAEL-3589 : Improvement: Java Generate Random String
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Greg 2019-12-22 15:53:59 -05:00 committed by GitHub
commit 8469804de9
1 changed files with 103 additions and 72 deletions
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core-java-modules/core-java-strings/src/test/java/com/baeldung/randomstrings/RandomStringsUnitTest.java
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@ -1,72 +1,103 @@
package com.baeldung.randomstrings; package com.baeldung.randomstrings;
import org.apache.commons.lang3.RandomStringUtils; import org.apache.commons.lang3.RandomStringUtils;
import org.junit.Test; import org.junit.Test;
import org.slf4j.Logger; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import org.slf4j.LoggerFactory;
import java.nio.charset.Charset; import java.nio.charset.Charset;
import java.util.Random; import java.util.Random;
public class RandomStringsUnitTest { public class RandomStringsUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(RandomStringsUnitTest.class); private static final Logger LOG = LoggerFactory.getLogger(RandomStringsUnitTest.class);
@Test @Test
public void givenUsingPlainJava_whenGeneratingRandomStringUnbounded_thenCorrect() { public void givenUsingPlainJava_whenGeneratingRandomStringUnbounded_thenCorrect() {
final byte[] array = new byte[7]; // length is bounded by 7 byte[] array = new byte[7]; // length is bounded by 7
new Random().nextBytes(array); new Random().nextBytes(array);
final String generatedString = new String(array, Charset.forName("UTF-8")); String generatedString = new String(array, Charset.forName("UTF-8"));
LOG.debug(generatedString); LOG.debug(generatedString);
} }
@Test @Test
public void givenUsingPlainJava_whenGeneratingRandomStringBounded_thenCorrect() { public void givenUsingPlainJava_whenGeneratingRandomStringBounded_thenCorrect() {
final int leftLimit = 97; // letter 'a' int leftLimit = 97; // letter 'a'
final int rightLimit = 122; // letter 'z' int rightLimit = 122; // letter 'z'
final int targetStringLength = 10; int targetStringLength = 10;
final Random random = new Random(); Random random = new Random();
final StringBuilder buffer = new StringBuilder(targetStringLength); StringBuilder buffer = new StringBuilder(targetStringLength);
for (int i = 0; i < targetStringLength; i++) { for (int i = 0; i < targetStringLength; i++) {
final int randomLimitedInt = leftLimit + (int) (random.nextFloat() * (rightLimit - leftLimit + 1)); int randomLimitedInt = leftLimit + (int) (random.nextFloat() * (rightLimit - leftLimit + 1));
buffer.append((char) randomLimitedInt); buffer.append((char) randomLimitedInt);
} }
final String generatedString = buffer.toString(); String generatedString = buffer.toString();
LOG.debug(generatedString); LOG.debug(generatedString);
} }
@Test @Test
public void givenUsingApache_whenGeneratingRandomString_thenCorrect() { public void givenUsingJava8_whenGeneratingRandomAlphabeticString_thenCorrect() {
final String generatedString = RandomStringUtils.random(10); int leftLimit = 97; // letter 'a'
int rightLimit = 122; // letter 'z'
LOG.debug(generatedString); int targetStringLength = 10;
} Random random = new Random();
@Test String generatedString = random.ints(leftLimit, rightLimit + 1)
public void givenUsingApache_whenGeneratingRandomAlphabeticString_thenCorrect() { .limit(targetStringLength)
final String generatedString = RandomStringUtils.randomAlphabetic(10); .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
.toString();
LOG.debug(generatedString);
} LOG.debug(generatedString);
}
@Test
public void givenUsingApache_whenGeneratingRandomAlphanumericString_thenCorrect() { @Test
final String generatedString = RandomStringUtils.randomAlphanumeric(10); public void givenUsingJava8_whenGeneratingRandomAlphanumericString_thenCorrect() {
int leftLimit = 48; // numeral '0'
LOG.debug(generatedString); int rightLimit = 122; // letter 'z'
} int targetStringLength = 10;
Random random = new Random();
@Test
public void givenUsingApache_whenGeneratingRandomStringBounded_thenCorrect() { String generatedString = random.ints(leftLimit, rightLimit + 1)
final int length = 10; .filter(i -> (i <= 57 || i >= 65) && (i <= 90 || i >= 97))
final boolean useLetters = true; .limit(targetStringLength)
final boolean useNumbers = false; .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
final String generatedString = RandomStringUtils.random(length, useLetters, useNumbers); .toString();
LOG.debug(generatedString); LOG.debug(generatedString);
} }
} @Test
public void givenUsingApache_whenGeneratingRandomString_thenCorrect() {
String generatedString = RandomStringUtils.random(10);
LOG.debug(generatedString);
}
@Test
public void givenUsingApache_whenGeneratingRandomAlphabeticString_thenCorrect() {
String generatedString = RandomStringUtils.randomAlphabetic(10);
LOG.debug(generatedString);
}
@Test
public void givenUsingApache_whenGeneratingRandomAlphanumericString_thenCorrect() {
String generatedString = RandomStringUtils.randomAlphanumeric(10);
LOG.debug(generatedString);
}
@Test
public void givenUsingApache_whenGeneratingRandomStringBounded_thenCorrect() {
int length = 10;
boolean useLetters = true;
boolean useNumbers = false;
String generatedString = RandomStringUtils.random(length, useLetters, useNumbers);
LOG.debug(generatedString);
}
}