refutils.util.FieldExtractor Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of reflection-utils Show documentation

A utility library to handle Java reflection with ease

The newest version!

package refutils.util;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Set;
import java.util.TreeSet;

/**
 * Extracts all visible fields for a class. Visible fields are private, package protected, protected
 * and public fields of the class and package protected, protected and public fields of existing
 * superclasses. Fields that are hidden (same name and type) by a subclass are not available.
 * Internal fields in classes from Sun are not available
 */
class FieldExtractor {
  private final Set allFields = new TreeSet<>(new FieldComparator());
  private final Class instanceClass;

  /**
   * Extracts all fields for a class
   *
   * @param instanceClass the instance containing the fields
   */
  FieldExtractor(Class instanceClass) {
    this.instanceClass = instanceClass;
    scanForFields();
  }

  private void scanForFields() {
    allFields.addAll(Arrays.asList(instanceClass.getDeclaredFields()));
    scanForFieldsWithoutPrivate(instanceClass.getSuperclass());
  }

  private void scanForFieldsWithoutPrivate(Class clazz) {
    if (clazz == null) {
      return;
    }
    String packageName = clazz.getPackage().getName();
    if (startsWith(packageName, "java.", "javax.", "sun.", "sunw.")) {
      return;
    }

    Field[] declaredFields = clazz.getDeclaredFields();
    for (Field field : declaredFields) {
      if (!(Modifier.isPrivate(field.getModifiers()))) {
        allFields.add(field);
      }
    }
    scanForFieldsWithoutPrivate(clazz.getSuperclass());
  }

  private boolean startsWith(String string, String... matches) {
    for (String match : matches) {
      if (string.startsWith(match)) {
        return true;
      }
    }
    return false;
  }

  /** Returns all visible fields. */
  Set getAllFields() {
    return allFields;
  }
}