I'd like to write a method that converts CamelCase into a human-readable name.
Here's the test case:
public void testSplitCamelCase() {
assertEquals("lowercase", splitCamelCase("lowercase"));
assertEquals("Class", splitCamelCase("Class"));
assertEquals("My Class", splitCamelCase("MyClass"));
assertEquals("HTML", splitCamelCase("HTML"));
assertEquals("PDF Loader", splitCamelCase("PDFLoader"));
assertEquals("A String", splitCamelCase("AString"));
assertEquals("Simple XML Parser", splitCamelCase("SimpleXMLParser"));
assertEquals("GL 11 Version", splitCamelCase("GL11Version"));
}
This works with your testcases:
static String splitCamelCase(String s) {
return s.replaceAll(
String.format("%s|%s|%s",
"(?<=[A-Z])(?=[A-Z][a-z])",
"(?<=[^A-Z])(?=[A-Z])",
"(?<=[A-Za-z])(?=[^A-Za-z])"
),
" "
);
}
Here's a test harness:
String[] tests = {
"lowercase", // [lowercase]
"Class", // [Class]
"MyClass", // [My Class]
"HTML", // [HTML]
"PDFLoader", // [PDF Loader]
"AString", // [A String]
"SimpleXMLParser", // [Simple XML Parser]
"GL11Version", // [GL 11 Version]
"99Bottles", // [99 Bottles]
"May5", // [May 5]
"BFG9000", // [BFG 9000]
};
for (String test : tests) {
System.out.println("[" + splitCamelCase(test) + "]");
}
It uses zero-length matching regex with lookbehind and lookforward to find where to insert spaces. Basically there are 3 patterns, and I use String.format
to put them together to make it more readable.
The three patterns are:
XMLParser AString PDFLoader
/\ /\ /\
MyClass 99Bottles
/\ /\
GL11 May5 BFG9000
/\ /\ /\
Using zero-length matching lookarounds to split: