@Override
    protected boolean execute(
            CtClass inputClass,
            String inputClassName,
            CtConstructor constructor)
            throws CannotCompileException, NotFoundException {

        if (!isMatchConstructorSource(inputClassName, constructor)) {
            return false;
        }
        String target = getTarget();
        String name = constructor.getName();

        target = getReplaceStatement(inputClassName, constructor, target);

        if (isAsBefore()) {
            constructor.insertBeforeBody(target);
            Logger.warning(getPrettyName() + " by before: " + target
                    + " at " + inputClassName + ".java" + ":" + name);
        }
        if (isAsAfter()) {
            constructor.insertAfter(target);
            Logger.warning(getPrettyName() + " by after: " + target
                    + " at " + inputClassName + ".java" + ":" + name);
        }
        return false;
    }
Transform that inserts custom code at the pointcut where constructor executes.
plugin/src/main/groovy/com/didichuxing/tools/droidassist/transform/insert/ConstructorExecutionInsertTransformer.java