GetterReflection.java

package uk.kludje.experimental.property.reflect;

import java.lang.reflect.Method;

/**
 * A source of method references for working with methods.
 */
public final class GetterReflection {

  private static final String GETTER = "^get.+";
  private static final String ISSER = "^is.+";

  private GetterReflection() {}

  public static boolean excludeNothing(Method method) {
    return false;
  }

  public static boolean excludeNonBeanProperties(Method method) {
    String name = method.getName();
    return name.matches(GETTER)
      || (returnsBoolean(method) && name.matches(ISSER));
  }

  private static boolean returnsBoolean(Method method) {
    Class<?> returnType = method.getReturnType();
    return returnType == Boolean.TYPE
      || returnType == Boolean.class;
  }

  public static String methodToPropertyName(Method method) {

    String name = method.getName();
    int firstIndex;

    if (name.matches(GETTER)) {
      firstIndex = 4;
    } else if (name.matches(ISSER)) {
      firstIndex = 3;
    } else {
      throw new IllegalArgumentException("Method name '" + name + "' is not a recognised getter");
    }

    char first = name.charAt(firstIndex);
    char lower = Character.toLowerCase(first);
    return lower + name.substring(firstIndex);
  }
}