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< > BotCompany Repo | #1001101 - "getOpt" function (get field by reflection, return null if not there)

JavaX fragment (include)

static O getOpt(O o, S field) {
  ret getOpt_cached(o, field);
}

static O mapMethodLike getOpt(S field, O o) {
  ret getOpt_cached(o, field);
}

static Object getOpt_raw(Object o, String field) ctex {
  Field f = getOpt_findField(o.getClass(), field);
  if (f == null) null;
  makeAccessible(f);
  ret f.get(o);
}

// access of static fields is not yet optimized
static O getOpt(Class c, String field) ctex {
  if (c == null) null;
  Field f = getOpt_findStaticField(c, field);
  if (f == null) null;
  makeAccessible(f);
  ret f.get(null);
}

static Field getOpt_findStaticField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field) && (f.getModifiers() & java.lang.reflect.Modifier.STATIC) != 0)
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  ret null;
}

Author comment

Began life as a copy of #1000597

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Comments [hide]

ID Author/Program Comment Date
1208 stefan getOpt can be passed a null 1st argument - then it just returns null. Useful for cascaded optionality, e.g.:

static S printableUserName() {
// Custom or Slack name, depending on what's available
ret or((S) callOpt(getBot("#1002355"), "getUserName"), getUserName());
}
2016-01-27 01:28:45

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Snippet ID: #1001101
Snippet name: "getOpt" function (get field by reflection, return null if not there)
Eternal ID of this version: #1001101/9
Text MD5: 91e56345ffd108ce4905ab8367478f85
Author: stefan
Category: javax
Type: JavaX fragment (include)
Public (visible to everyone): Yes
Archived (hidden from active list): No
Created/modified: 2019-08-31 14:55:44
Source code size: 894 bytes / 34 lines
Pitched / IR pitched: No / No
Views / Downloads: 767 / 6537
Version history: 8 change(s)
Referenced in: [show references]

Formerly at http://tinybrain.de/1001101 & http://1001101.tinybrain.de