CollectionSaveStatementWriter.java

/*
 * Copyright 2015 Workday, Inc.
 *
 * This software is available under the MIT license.
 * Please see the LICENSE.txt file in this project.
 */

package com.workday.postman.codegen;

import com.squareup.javawriter.JavaWriter;
import com.workday.meta.Initializers;
import com.workday.meta.InvalidTypeException;
import com.workday.meta.MetaTypes;
import com.workday.postman.parceler.CollectionBundler;
import com.workday.postman.util.Names;

import java.io.IOException;
import java.util.Collection;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.TypeMirror;
import javax.tools.Diagnostic;

/**
 * @author nathan.taylor
 * @since 2015-04-06
 */
class CollectionSaveStatementWriter implements SaveStatementWriter {

    private final MetaTypes metaTypes;
    private final ProcessingEnvironment processingEnv;
    private final Initializers initializers;

    CollectionSaveStatementWriter(ParcelerGenerator parcelerGenerator) {
        this.metaTypes = parcelerGenerator.metaTypes;
        this.processingEnv = parcelerGenerator.processingEnv;

        initializers = new Initializers(metaTypes);
    }

    @Override
    public boolean isApplicable(VariableElement field) {
        return metaTypes.isSubtypeErasure(field.asType(), Collection.class);
    }

    @Override
    public void writeFieldReadStatement(VariableElement field,
                                        Collection<ExecutableElement> postCreateChildMethods,
                                        JavaWriter writer) throws IOException {
        DeclaredType type = (DeclaredType) field.asType();
        TypeMirror itemType = type.getTypeArguments().get(0);
        TypeMirror itemTypeErasure = processingEnv.getTypeUtils().erasure(itemType);

        String collectionInitializer;
        try {
            collectionInitializer = initializers.findCollectionInitializer(type);
        } catch (InvalidTypeException e) {
            processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, e.getMessage(), field);
            collectionInitializer = "null";
        }
        writer.beginControlFlow("if (bundle.containsKey(\"%s\"))", field.getSimpleName());
        writer.emitStatement("object.%s = %s", field.getSimpleName(), collectionInitializer);
        writer.emitStatement(
                "%1$s.readCollectionFromBundle(object.%2$s, bundle, %3$s.class, \"%2$s\")",
                CollectionBundler.class.getCanonicalName(),
                field.getSimpleName(),
                itemTypeErasure);

        writePostCreateChildMethodCalls(field, itemType, postCreateChildMethods, writer);
        writer.endControlFlow();
    }

    @Override
    public void writeFieldWriteStatement(VariableElement field, JavaWriter writer)
            throws IOException {
        DeclaredType type = (DeclaredType) field.asType();
        TypeMirror itemType = type.getTypeArguments().get(0);
        TypeMirror itemTypeErasure = processingEnv.getTypeUtils().erasure(itemType);

        writer.beginControlFlow("if (object.%s != null)", field.getSimpleName());
        writer.emitStatement(
                "%1$s.writeCollectionToBundle(object.%2$s, bundle, %3$s.class, \"%2$s\")",
                CollectionBundler.class.getCanonicalName(),
                field.getSimpleName(),
                itemTypeErasure);
        writer.endControlFlow();
    }

    private void writePostCreateChildMethodCalls(VariableElement field,
                                                 TypeMirror itemType,
                                                 Collection<ExecutableElement>
                                                         postCreateChildMethods,
                                                 JavaWriter writer) throws IOException {

        if (!postCreateChildMethods.isEmpty() && metaTypes.isSubtype(itemType, Names.PARCELABLE)) {
            writer.beginControlFlow("for (Object child : object.%s)", field.getSimpleName());
            for (ExecutableElement method : postCreateChildMethods) {
                writer.emitStatement("object.%s(child)", method.getSimpleName());
            }
            writer.endControlFlow();
        }
    }

}