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change method to return Optionals #4464

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Merged
pauljervis merged 2 commits into from
Jun 17, 2018
Merged

change method to return Optionals #4464

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c45b066
change method to return Optionals
Jun 11, 2018
e5dbbc4
add check for empty Optional
Jun 16, 2018
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12 changes: 6 additions & 6 deletions core-java/src/main/java/com/baeldung/extension/Extension.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,18 +3,18 @@
import com.google.common.io.Files;
import org.apache.commons.io.FilenameUtils;

import java.util.Optional;

public class Extension {
//Instead of file name we can also specify full path of a file eg. /baeldung/com/demo/abc.java
public String getExtensionByApacheCommonLib(String filename) {
return FilenameUtils.getExtension(filename);
}

public String getExtensionByStringHandling(String filename) {
String fileExtension = "";
if (filename.contains(".") && filename.lastIndexOf(".") != 0) {
fileExtension = filename.substring(filename.lastIndexOf(".") + 1);
}
return fileExtension;
public Optional<String> getExtensionByStringHandling(String filename) {
return Optional.ofNullable(filename)
.filter(f -> f.contains("."))
.map(f -> f.substring(filename.lastIndexOf(".") + 1));
}

public String getExtensionByGuava(String filename) {
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7 changes: 5 additions & 2 deletions core-java/src/test/java/com/baeldung/extension/ExtensionUnitTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@
import org.junit.Assert;
import org.junit.Test;

import java.util.Optional;

public class ExtensionUnitTest {
private Extension extension = new Extension();

Expand All @@ -16,8 +18,9 @@ public void getExtension_whenApacheCommonIO_thenExtensionIsTrue() {
@Test
public void getExtension_whenStringHandle_thenExtensionIsTrue() {
String expectedExtension = "java";
String actualExtension = extension.getExtensionByStringHandling("Demo.java");
Assert.assertEquals(expectedExtension, actualExtension);
Optional<String> actualExtension = extension.getExtensionByStringHandling("Demo.java");
Assert.assertTrue(actualExtension.isPresent());
actualExtension.ifPresent(ext -> Assert.assertEquals(expectedExtension,ext));
}

@Test
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