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Doc clarifications (Java vectors, test working dir, benchmark fix).

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Change-Id: If8cc05669d82df892e1d4e11f7fbbd68b2dc05bf
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Wouter van Oortmerssen
2014-06-23 13:33:34 -07:00
parent 65cfa18855
commit ff0d7a89d8
6 changed files with 24 additions and 8 deletions
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docs/html/md__java_usage.html
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@@ -59,6 +59,7 @@ Monster monster = Monster.getRootAsMonster(bb);
</pre><p>Now you can access values much like C++: </p><pre class="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 &amp; 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><pre class="fragment">for (int i = 0; i &lt; monster.inventory_length(); i++)
monster.inventory(i); // do something here
@@ -78,6 +79,7 @@ int mon = Monster.endMonster(fbb);
for (byte i = 4; i &gt;=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>
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