net.je2sh.annotations.CommandProcessor Maven / Gradle / Ivy
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/*
* MIT License
*
* Copyright (c) 2017 JeeSh
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package net.je2sh.annotations;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import com.beust.jcommander.Parameters;
import com.google.auto.service.AutoService;
import com.squareup.javapoet.AnnotationSpec;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.ParameterizedTypeName;
import com.squareup.javapoet.TypeName;
import com.squareup.javapoet.TypeSpec;
import com.squareup.javapoet.WildcardTypeName;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.Processor;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.Name;
import javax.lang.model.element.PackageElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.TypeMirror;
import javax.tools.Diagnostic;
import net.je2sh.core.Command;
import net.je2sh.core.CommandProvider;
/**
* Annotation processor capable of understanding classes annotated with {@link Parameters} and
* generating a {@link CommandProvider} for such commands.
*
* This processor uses JavaPoet to build
* the new class(es).
*/
@SupportedAnnotationTypes("com.beust.jcommander.Parameters")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
@AutoService(Processor.class)
public class CommandProcessor extends AbstractProcessor {
@Override
public boolean process(Set annotations, RoundEnvironment roundEnv) {
Map types = new HashMap<>();
TypeMirror expectedInterfaceType =
processingEnv.getElementUtils().getTypeElement(Command.class.getCanonicalName())
.asType();
PackageElement pkg = null;
for (TypeElement a : annotations) {
for (Element element : roundEnv.getElementsAnnotatedWith(a)) {
Parameters parameters =
Objects.requireNonNull(element.getAnnotation(Parameters.class));
TypeMirror typeMirror = element.asType();
if (pkg == null) {
pkg = processingEnv.getElementUtils().getPackageOf(element);
}
if (!processingEnv.getTypeUtils().isAssignable(typeMirror, expectedInterfaceType)) {
processingEnv.getMessager()
.printMessage(Diagnostic.Kind.ERROR,
String.format("Class %s does not implement %s",
element.getSimpleName(),
Command.class.getCanonicalName()));
}
for (String commandName : extractCommandNames(element.getSimpleName(),
parameters.commandNames())) {
types.put(commandName, typeMirror);
}
}
}
if (!types.isEmpty()) {
try {
writeFile(types, pkg);
}
catch (IOException e) {
processingEnv.getMessager()
.printMessage(Diagnostic.Kind.ERROR,
"Unable to process jeesh annotations: " +
e.getMessage());
}
}
return false;
}
private void writeFile(Map types,
PackageElement pkg) throws IOException
{
TypeName wildcardClass = ParameterizedTypeName.get(ClassName.get(Class.class),
WildcardTypeName
.subtypeOf(Command.class));
ParameterizedTypeName returnType =
ParameterizedTypeName.get(ClassName.get(Map.class),
ClassName.get(String.class), wildcardClass);
MethodSpec.Builder methodBuilder =
MethodSpec.methodBuilder("getCommands")
.addAnnotation(Override.class)
.addModifiers(Modifier.PUBLIC)
.returns(returnType)
.addStatement("$T knownTypes = new $T<>()",
returnType, ClassName.get(HashMap.class));
for (Map.Entry entry : types.entrySet()) {
methodBuilder.addStatement("knownTypes.put($S, $T.class)", entry.getKey(),
entry.getValue());
}
MethodSpec getcommands = methodBuilder.addStatement("return knownTypes")
.build();
AnnotationSpec autoServiceAnnotation =
AnnotationSpec.builder(AutoService.class)
.addMember("value", "$T.class", CommandProvider.class)
.build();
TypeSpec commandProvider = TypeSpec.classBuilder("CommandProviderImpl")
.addModifiers(Modifier.PUBLIC, Modifier.FINAL)
.addSuperinterface(CommandProvider.class)
.addAnnotation(autoServiceAnnotation)
.addMethod(getcommands)
.build();
JavaFile javaFile = JavaFile.builder(pkg.getQualifiedName().toString() + ".provider",
commandProvider).build();
javaFile.writeTo(processingEnv.getFiler());
}
private List extractCommandNames(Name elementName, String[] commandNames) {
if (commandNames.length == 0) {
String className = elementName.toString();
StringBuilder builder = new StringBuilder()
.append(Character.toLowerCase(className.charAt(0)))
.append(className.substring(1, className.length()));
return Collections.singletonList(builder.toString());
}
return Arrays.asList(commandNames);
}
}