27 lines
841 B
Java
27 lines
841 B
Java
// validating/Inverter4.java
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// (c)2016 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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package validating;
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import static java.lang.Character.*;
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public class Inverter4 implements StringInverter {
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static final String ALLOWED =
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"abcdefghijklmnopqrstuvwxyz ,." +
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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public String invert(String str) {
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if(str.length() > 30)
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throw new RuntimeException("argument too long!");
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String result = "";
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for(int i = 0; i < str.length(); i++) {
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char c = str.charAt(i);
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if(ALLOWED.indexOf(c) == -1)
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throw new RuntimeException(c + " Not allowed");
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result += isUpperCase(c) ?
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toLowerCase(c) :
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toUpperCase(c);
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}
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return result;
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}
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}
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