Here is a resource for middle school learners of Indonesian and Japanese, from the Asia Education Foundation in Australia:
This multimedia Indonesian reader resource comprises 30 passages, organized in 6 broad themes: Dunia Saya, Kehidupan Sehari-hari, Makanan & Kesehatan, Agama & Kepercayaan, Dunia Manusia, and Lingkungan Kita.
Within each theme, there are 5 passages, ranked from easiest to hardest. For example, the passages in Dunia Saya are generally pitched at lower year levels, whereas those in Lingkungan Kita are generally aimed at higher year levels within the middle school.
The Japanese resource comprises 35 passages, organized into seven broad themes: All about me, World of words, Places, The world around me, Food and health, My world, and Getting around.
In addition to student resources, the readers also contain information for the teacher, acknowledgements and a help section.
The readers are available at http://www.asiaeducation.edu.au/sites/readers/main.htm