38 lines
929 B
Java
38 lines
929 B
Java
// streams/CreatingOptionals.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.util.*;
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import java.util.stream.*;
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import java.util.function.*;
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class CreatingOptionals {
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static void
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test(String testName, Optional<String> opt) {
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System.out.println(" === " + testName + " === ");
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System.out.println(opt.orElse("Null"));
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}
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public static void main(String[] args) {
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test("empty", Optional.empty());
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test("of", Optional.of("Howdy"));
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try {
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test("of", Optional.of(null));
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} catch(Exception e) {
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System.out.println(e);
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}
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test("ofNullable", Optional.ofNullable("Hi"));
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test("ofNullable", Optional.ofNullable(null));
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}
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}
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/* Output:
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=== empty ===
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Null
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=== of ===
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Howdy
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java.lang.NullPointerException
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=== ofNullable ===
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Hi
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=== ofNullable ===
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Null
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*/
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