37 lines
900 B
Java
37 lines
900 B
Java
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// enumerations/SmartCasting.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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// {NewFeature} Since JDK 16
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public class SmartCasting {
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static void dumb(Object x) {
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if(x instanceof String) {
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String s = (String)x;
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if(s.length() > 0) {
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System.out.format(
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"%d %s%n", s.length(), s.toUpperCase());
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}
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}
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}
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static void smart(Object x) {
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if(x instanceof String s && s.length() > 0) {
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System.out.format(
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"%d %s%n", s.length(), s.toUpperCase());
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}
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}
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static void wrong(Object x) {
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// "Or" never works:
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// if(x instanceof String s || s.length() > 0) {}
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// error: cannot find symbol ^
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}
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public static void main(String[] args) {
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dumb("dumb");
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smart("smart");
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}
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}
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/* Output:
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4 DUMB
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5 SMART
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*/
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