</pre><p>Then, build as normal for your platform. This should result in a <code>flatc</code> executable, essential for the next steps. Note that to use clang instead of gcc, you may need to set up your environment variables, e.g. <code>CC=/usr/bin/clang CXX=/usr/bin/clang++ cmake -G "Unix Makefiles"</code>.</p>
<p>Optionally, run the <code>flattests</code> executable. to ensure everything is working correctly on your system. If this fails, please contact us!</p>
<p>Optionally, run the <code>flattests</code> executable to ensure everything is working correctly on your system. If this fails, please contact us!</p>
<p>Note that you MUST be in the root of the FlatBuffers distribution when you run 'flattests' (and the samples), or it will fail to load its files.</p>
<p>Building should also produce two sample executables, <code>sample_binary</code> and <code>sample_text</code>, see the corresponding <code>.cpp</code> file in the samples directory.</p>
<p>There is an <code>android</code> directory that contains all you need to build the test executable on android (use the included <code>build_apk.sh</code> script, or use <code>ndk_build</code> / <code>adb</code> etc. as usual). Upon running, it will output to the log if tests succeeded or not.</p>
<p>There is usually no runtime to compile, as the code consists of a single header, <code>include/flatbuffers/flatbuffers.h</code>. You should add the <code>include</code> folder to your include paths. If you wish to be able to load schemas and/or parse text into binary buffers at runtime, you additionally need the other headers in <code>include/flatbuffers</code>. You must also compile/link <code>src/idl_parser.cpp</code> (and <code>src/idl_gen_text.cpp</code> if you also want to be able convert binary to text).</p>
</pre><p>Now you can access values much like C++: </p><preclass="fragment">short hp = monster.hp();
Vec3 pos = monster.pos();
</pre><p>Note that whenever you access a new object like in the <code>pos</code> example above, a new temporary accessor object gets created. If your code is very performance sensitive (you iterate through a lot of objects), there's a second <code>pos()</code> method to which you can pass a <code>Vec3</code> object you've already created. This allows you to reuse it across many calls and reduce the amount of object allocation (and thus garbage collection) your program does.</p>
<p>Java does not support unsigned scalars. This means that any unsigned types you use in your schema will actually be represented as a signed value. This means all bits are still present, but may represent a negative value when used. For example, to read a <code>byte b</code> as an unsigned number, you can do: <code>(short)(b & 0xFF)</code></p>
<p>Sadly the string accessors currently always create a new string when accessed, since FlatBuffer's UTF-8 strings can't be read in-place by Java.</p>
<p>Vector access is also a bit different from C++: you pass an extra index to the vector field accessor. Then a second method with the same name suffixed by <code>_length</code> let's you know the number of elements you can access: </p><preclass="fragment">for (int i = 0; i < monster.inventory_length(); i++)
monster.inventory(i); // do something here
...
...
@@ -78,6 +79,7 @@ int mon = Monster.endMonster(fbb);
for (byte i = 4; i >=0; i--) fbb.addByte(i);
int inv = fbb.endVector();
</pre><p>You can use the generated method <code>startInventoryVector</code> to conveniently call <code>startVector</code> with the right element size. You pass the number of elements you want to write. You write the elements backwards since the buffer is being constructed back to front.</p>
<p>There are <code>add</code> functions for all the scalar types. You use <code>addOffset</code> for any previously constructed objects (such as other tables, strings, vectors). For structs, you use the appropriate <code>create</code> function in-line, as shown above in the <code>Monster</code> example.</p>
<h2>Text Parsing</h2>
<p>There currently is no support for parsing text (Schema's and JSON) directly from Java, though you could use the C++ parser through JNI. Please see the C++ documentation for more on text parsing. </p>
