ClassFileGsonDefinitionModelStore.java

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package com.salesforce.apt.graph.model.storage.apt;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

import javax.lang.model.element.Modifier;

import com.google.gson.internal.JavaVersion;
import com.salesforce.apt.graph.model.DefinitionModel;
import com.salesforce.apt.graph.model.storage.DefinitionOutputStreamProvider;
import com.salesforce.apt.graph.model.storage.ResourceLoader;
import com.salesforce.apt.graph.model.storage.classpath.FileStore;
import com.salesforce.apt.graph.model.storage.classpath.GsonDefinitionModelStore;
import com.squareup.javapoet.AnnotationSpec;
import com.squareup.javapoet.FieldSpec;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.TypeSpec;

public class ClassFileGsonDefinitionModelStore extends GsonDefinitionModelStore {

  private static final String GENERATED_JAVA9 = "javax.annotation.processing.Generated";

  private static final String GENERATED_JAVA8 = "javax.annotation.Generated";

  
  public ClassFileGsonDefinitionModelStore(ResourceLoader resourceLocator, DefinitionOutputStreamProvider definitionModelToStore) {
    super(resourceLocator, definitionModelToStore);
  }
  
  @Override
  public boolean store(DefinitionModel model) {
    String packageName = model.getSourcePackage();
    String className = model.getSourceClass() + "_" + FileStore.STANDARD.getPath();
    String data = getGson().toJson(model);
    
    FieldSpec fieldSpec = FieldSpec.builder(String.class, AptResourceLoader.FIELD_NAME)
        .addModifiers(Modifier.PRIVATE, Modifier.FINAL)
        .initializer("$S", data)
        .addAnnotation(AnnotationSpec.builder(SuppressWarnings.class).addMember("value", "$S", "unused").build())
        .build();

    TypeSpec classSpec = TypeSpec.classBuilder(className)
        .addModifiers(Modifier.PUBLIC)
        .addField(fieldSpec)
        .addAnnotation(AnnotationSpec.builder(getGeneratedAnnotationClass()).addMember("value", "$S", "SpringApt").build())
        .build();
    
    JavaFile javaFile = JavaFile.builder(packageName, classSpec)
        .build();

    try {
      OutputStream stream = getDefinitionOutputStreamProvider().store(model);
      try {
        stream.write(javaFile.toString().getBytes(StandardCharsets.UTF_8));
      } finally {
        stream.close();
      }
      model.setSha256(bytesToHex(getSha256Digest().digest(data.getBytes(StandardCharsets.UTF_8))));
      return true;
    } catch (IOException ex) {
      throw new IllegalStateException("Could not store model to class", ex);
    }
  }
  
  private Class<?> getGeneratedAnnotationClass() {
    final String generatedClass = JavaVersion.isJava9OrLater() ? GENERATED_JAVA9 : GENERATED_JAVA8;
    try {
      return Class.forName(generatedClass);
    } catch (ClassNotFoundException ex) {
      throw new RuntimeException(ex);
    }
  }
}