|
The Java Developers Almanac 1.4 |
|
e81. Determining If a String Is a Legal Java IdentifierBriefly, a valid Java identifier must start with a Unicode letter, underscore, or dollar sign ($). The other characters, if any, can
be a Unicode letter, underscore, dollar sign, or digit.
For more details, see http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html. // Returns true if s is a legal Java identifier.
public static boolean isJavaIdentifier(String s) {
if (s.length() == 0 || !Character.isJavaIdentifierStart(s.charAt(0))) {
return false;
}
for (int i=1; i<s.length(); i++) {
if (!Character.isJavaIdentifierPart(s.charAt(i))) {
return false;
}
}
return true;
}
// Some examples
boolean b = isJavaIdentifier("my_var"); // true
b = isJavaIdentifier("my_var.1"); // false
b = isJavaIdentifier("$my_var"); // true
b = isJavaIdentifier("\u0391var"); // true
b = isJavaIdentifier("_"); // true
b = isJavaIdentifier("$"); // true
b = isJavaIdentifier("1$my_var"); // false
e71. Comparing Strings e72. Determining If a String Contains a Substring e73. Getting a Substring from a String e74. Searching a String for a Character or a Substring e75. Replacing Characters in a String e76. Replacing Substrings in a String e77. Converting a String to Upper or Lower Case e78. Converting a Primitive Type Value to a String e79. Converting Between Unicode and UTF-8 e80. Determining a Character's Unicode Block
© 2002 Addison-Wesley. |