Can I use regular expressions to find a method on a class in java?
I know how to find a method in java using a fixed string,
someClass.getMethod("foobar", argTypes);
but is there a way to use a regular expression rather than a fixed string to find a method on a given class?
An example of the usage might be if I wanted to find a method that was called either "foobar" or "fooBar". Using a regular expression like "foo[Bb]ar" would match either of these method names.
Asked by: Max930 | Posted: 21-01-2022
Answer 1
You should apply your regexp on getDeclaredMethods() reflection method (or GetMethods() if you want only the public ones).
[Warning: both methods will throw a SecurityException if there is a security manager.]
You apply it on each name of each method returned by getDeclaredMethod() and only memorize in a Collection the compliant Methods.
Something like!
try
{
final Pattern aMethodNamePattern = Pattern.compile("foo[Bb]ar");
final List<Method> someMethods = aClass.getDeclaredMethods();
final List<Method> someCompliantMethods = new ArrayList<Method>();
for(final Method aMethod: someMethods)
{
final String aMethodName = aMethod.getName();
final Matcher aMethodNameMatcher = aMethodNamePattern.getMatcher(aMethodName);
if(aMethodNameMatcher.matches() == true)
{
someCompliantMethods.add(aMethod);
}
}
catch(...) // catch all exceptions like SecurityException, IllegalAccessException, ...
Answer 2
Not directly. You could loop over all the methods and check each.
Pattern p = Pattern.compile("foo[Bb]ar");
for(Method m : someClass.getMethods()) {
if(p.matcher(m.getName()).matches()) {
return m;
}
}
Answer 3
You could do it by iterating over ALL the methods on a class and matching them that way.
Not that simple, but it would do the trick
ArrayList<Method> matches = new ArrayList<Method>();
for(Method meth : String.class.getMethods()) {
if (meth.getName().matches("lengt.")){
matches.add(meth);
}
}
Answer 4
No, you can't do that, but you can get a list of the method a class has and apply the regexp to them.
Method[] getMethods( String regexp, Class clazz, Object ... argTypes ){
List<Method> toReturn = new ArrayList<Method>();
for( Method m : clazz.getDeclaredMethods() ){
if( m.getName().matches( regExp ) ) { // validate argTypes aswell here...
toReturn.add( m );
}
}
return toReturn.toArray();
}
Well something like that....
Answered by: Sawyer964 | Posted: 22-02-2022Answer 5
When I want look for some method using simple name pattern I use this org.reflections
For example looking for some methods which are public and name start with get:
Set<Method> getters = ReflectionUtils.getAllMethods(SomeClass.class, ReflectionUtils.withModifier(Modifier.PUBLIC), ReflectionUtils.withPrefix("get"));
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