flatbuffers/samples/SampleBinary.java

/*
 * Copyright 2015 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Run this file with the `java_sample.sh` script.

import MyGame.Sample.Color;
import MyGame.Sample.Equipment;
import MyGame.Sample.Monster;
import MyGame.Sample.Vec3;
import MyGame.Sample.Weapon;

import com.google.flatbuffers.FlatBufferBuilder;

import java.nio.ByteBuffer;

class SampleBinary {
  // Example how to use FlatBuffers to create and read binary buffers.
  public static void main(String[] args) {
    FlatBufferBuilder builder = new FlatBufferBuilder(0);

    // Create some weapons for our Monster ('Sword' and 'Axe').
    int weaponOneName = builder.createString("Sword");
    short weaponOneDamage = 3;
    int weaponTwoName = builder.createString("Axe");
    short weaponTwoDamage = 5;

    // Use the `createWeapon()` helper function to create the weapons, since we set every field.
    int[] weaps = new int[2];
    weaps[0] = Weapon.createWeapon(builder, weaponOneName, weaponOneDamage);
    weaps[1] = Weapon.createWeapon(builder, weaponTwoName, weaponTwoDamage);

    // Serialize the FlatBuffer data.
    int name = builder.createString("Orc");
    byte[] treasure = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    int inv = Monster.createInventoryVector(builder, treasure);
    int weapons = Monster.createWeaponsVector(builder, weaps);
    int pos = Vec3.createVec3(builder, 1.0f, 2.0f, 3.0f);

    Monster.startMonster(builder);
    Monster.addPos(builder, pos);
    Monster.addName(builder, name);
    Monster.addColor(builder, Color.Red);
    Monster.addHp(builder, (short)300);
    Monster.addInventory(builder, inv);
    Monster.addWeapons(builder, weapons);
    Monster.addEquippedType(builder, Equipment.Weapon);
    Monster.addEquipped(builder, weaps[1]);
    int orc = Monster.endMonster(builder);

    builder.finish(orc); // You could also call `Monster.finishMonsterBuffer(builder, orc);`.

    // We now have a FlatBuffer that can be stored on disk or sent over a network.

    // ...Code to store to disk or send over a network goes here...

    // Instead, we are going to access it right away, as if we just received it.

    ByteBuffer buf = builder.dataBuffer();

    // Get access to the root:
    Monster monster = Monster.getRootAsMonster(buf);

    // Note: We did not set the `mana` field explicitly, so we get back the default value.
    assert monster.mana() == (short)150;
    assert monster.hp() == (short)300;
    assert monster.name().equals("Orc");
    assert monster.color() == Color.Red;
    assert monster.pos().x() == 1.0f;
    assert monster.pos().y() == 2.0f;
    assert monster.pos().z() == 3.0f;

    // Get and test the `inventory` FlatBuffer `vector`.
    for (int i = 0; i < monster.inventoryLength(); i++) {
      assert monster.inventory(i) == (byte)i;
    }

    // Get and test the `weapons` FlatBuffer `vector` of `table`s.
    String[] expectedWeaponNames = {"Sword", "Axe"};
    int[] expectedWeaponDamages = {3, 5};
    for (int i = 0; i < monster.weaponsLength(); i++) {
      assert monster.weapons(i).name().equals(expectedWeaponNames[i]);
      assert monster.weapons(i).damage() == expectedWeaponDamages[i];
    }

    // Get and test the `equipped` FlatBuffer `union`.
    assert monster.equippedType() == Equipment.Weapon;
    Weapon equipped = (Weapon)monster.equipped(new Weapon());
    assert equipped.name().equals("Axe");
    assert equipped.damage() == 5;

    System.out.println("The FlatBuffer was successfully created and verified!");
  }
}