AVRO-1918: Improve logical type documentation. Contributed by Gabor S…

…zadovszky.
samschlegel · Sep 27, 2016 · a92c8f5 · a92c8f5
1 parent 1296ce9
commit a92c8f5
Show file tree

Hide file tree

Showing 3 changed files with 32 additions and 0 deletions.
diff --git a/CHANGES.txt b/CHANGES.txt
@@ -29,6 +29,8 @@ Trunk (not yet released)
 
     AVRO-1919: Formalize the presence of build.sh. (Suraj Acharya via cutting)
 
+    AVRO-1918: Improve logical type documentation. (Gabor Szadovszky via cutting)
+
   BUG FIXES
 
     AVRO-1741: Python3: Fix error when codec is not in the header.

diff --git a/doc/src/content/xdocs/idl.xml b/doc/src/content/xdocs/idl.xml
@@ -206,6 +206,7 @@ error Kaboom {
       <p>A type reference in Avro IDL must be one of:</p>
       <ul>
         <li>A primitive type</li>
+        <li>A logical type</li>
         <li>A named schema defined prior to this usage in the same Protocol</li>
         <li>A complex type (array, map, or union)</li>
       </ul>
@@ -218,6 +219,29 @@ error Kaboom {
         </p>
       </section>
 
+      <section id="logical_types">
+        <title>Logical Types</title>
+        <p>Some of the logical types supported by Avro's JSON format are also supported by Avro IDL.
+        The currently supported types are:
+        </p>
+        <ul>
+          <li><code>decimal</code> (logical type <a href="spec.html#Decimal"><code>decimal</code></a>)</li>
+          <li><code>date</code> (logical type <a href="spec.html#Date"><code>date</code></a>)</li>
+          <li><code>time_ms</code> (logical type <a href="spec.html#Time+%28millisecond+precision%29"><code>time-millis</code></a>)</li>
+          <li><code>timestamp_ms</code> (logical type <a href="spec.html#Timestamp+%28millisecond+precision%29"><code>timestamp-millis</code></a>)</li>
+        </ul>
+        <p>For example:</p>
+        <source>
+record Job {
+  string jobid;
+  date submitDate;
+  time_ms submitTime;
+  timestamp_ms finishTime;
+  decimal(9,2) finishRatio;
+}
+        </source>
+      </section>
+
       <section id="schema_references">
         <title>References to Named Schemata</title>
         <p>If a named schema has already been defined in the same Avro IDL file, it may be referenced by name

diff --git a/lang/java/avro/src/main/java/org/apache/avro/specific/package.html b/lang/java/avro/src/main/java/org/apache/avro/specific/package.html
@@ -31,6 +31,12 @@
 
 <li>Record, enum, and fixed schemas generate Java class definitions.</li>
 
+<li>If a Conversion instance is available for the related logical type,
+  the value will be mapped to the object returned by that Conversion. The
+  logical type conversions for {@code date}, {@code time-millis}, {@code
+  timestamp-millis} and {@code decimal} are pre-defined in the class {@link
+  org.apache.avro.compiler.specific.SpecificCompiler SpecificCompiler}.</li>
+
 <li>All other types are mapped as in the {@link org.apache.avro.generic
   generic} API.</li>