You can create your own Metasitory implementation if you need to. In this guide, we’ll create one based on an XML file. I don’t think it’s a good idea but it’s good enough for the illustration.
So, the idea here’s that we want to generate an XML file which holds all the required information about metacode: masters, their metacode and the annotations they use.
First, we need to create a MetasitoryWriter. This class generates a metacode store, i.e.XML file. As in case of custom processor it must be a separate module. For this example we won’t use any modern tools to built XML and will be writing it as plain text:
public class XmlMetasitoryWriter implements MetasitoryWriter {
private Writer xml;
@Override
public void open(ProcessingContext processingContext) {
try {
FileObject fileObject = processingContext.processingEnv().getFiler().createResource(
StandardLocation.SOURCE_OUTPUT,
"",
"metasitory.xml");
xml = fileObject.openWriter();
xml.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
xml.append("<items>\n");
} catch (IOException e) {
throw new ProcessingException(e);
}
}
@Override
public void write(MetacodeContext metacodeContext) {
try {
String master = metacodeContext.masterElement().getQualifiedName().toString();
xml.append("\t<item master=\"")
.append(master)
.append("\" metacode=\"")
.append(MetacodeUtils.toMetacodeName(master))
.append("\">\n");
for (Class<? extends Annotation> annotation : metacodeContext.metacodeAnnotations()) {
xml.append("\t\t<annotation>")
.append(annotation.getCanonicalName())
.append("</annotation>\n");
}
xml.append("\t</item>\n");
} catch (IOException e) {
throw new ProcessingException(e);
}
}
@Override
public void close() {
try {
xml.append("</items>");
xml.close();
} catch (IOException e) {
throw new ProcessingException(e);
}
}
}
To say to Jeta to use this metasitory writer, add this property into jeta.properties:
metasitory.writer=com.example.metasitory.XmlMetasitoryWriter
After you assemble your project, we’ll see metasitory.xml file in build/generated/source/apt/main/ folder. Here’s the its listing for this sample:
<?xml version="1.0" encoding="UTF-8"?>
<items>
<item master="com.example.HelloWorldSample" metacode="com.example.HelloWorldSample_Metacode">
<annotation>com.example.SayHello</annotation>
</item>
</items>
We won’t create actual Metasitory implementation for this file. There’s no difficulties to do that though. It parses metasitory.xml and use its structure to search metacode by given Criteria. Here’s the listing of Metasitory interface it must implement in order to support Jeta API:
public interface Metasitory {
Collection<IMetacode<?>> search(Criteria criteria);
void add(Metasitory other);
}
You can refer to MapMetasitory implementation as the example.
This sample is available on GitHub.
