ToJsonGenerator.java

/*******************************************************************************
 * Copyright (c) 2017 Red Hat.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Red Hat - Initial Contribution
 *******************************************************************************/
package org.eclipse.che.api.languageserver.generator;

import org.eclipse.lsp4j.jsonrpc.messages.Either;

import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;

import static org.eclipse.che.api.languageserver.generator.DtoGenerator.INDENT;
import static org.eclipse.che.api.languageserver.generator.DtoGenerator.dtoName;

;

/**
 * This class generates code to convert dto object fields to json properties.
 *
 * @author Thomas Mäder
 */
public class ToJsonGenerator extends ConversionGenerator {
    private JsonImpl json;

    public ToJsonGenerator(JsonImpl json) {
        this.json = json;
    }

    public void generateToJson(String indent, PrintWriter out, Class<?> receiverClass, Method m) {
        String varName = fieldName(m) + "Val";
        Type paramType = m.getGenericParameterTypes()[0];
        String valueAccess = getterName(receiverClass, m) + "()";

        if (getRawClass(paramType).isPrimitive()) {
            generateToJson(indent, out, varName, getterName(receiverClass, m) + "()", paramType);
            out.println(
                    String.format(indent + INDENT + "result.%1$s(\"%2$s\", %3$s);", json.put(), fieldName(m), varName));
        } else {
            out.println(indent + String.format("if (%1$s == null) {", valueAccess));
            out.println(indent + INDENT + String.format("%1$s((%2$s)null);", m.getName(), paramType.getTypeName()));
            out.println(indent + "} else {");
            generateToJson(indent + INDENT, out, varName, getterName(receiverClass, m) + "()", paramType);
            out.println(
                    String.format(indent + INDENT + "result.%1$s(\"%2$s\", %3$s);", json.put(), fieldName(m), varName));
            out.println(indent + "}");
        }
    }

    private void generateToJson(String indent, PrintWriter out, String varName, String valueAccess, Type paramType) {
        if (List.class.isAssignableFrom(getRawClass(paramType))) {
            new ListConverter(varName, valueAccess, paramType).generateListConversion(indent, out);
        } else if (Map.class.isAssignableFrom(getRawClass(paramType))) {
            generateMapConversion(indent, out, varName, valueAccess, paramType);
        } else if (Either.class.isAssignableFrom(getRawClass(paramType))) {
            generateEitherConversion(indent, out, varName, valueAccess, paramType);
        } else {
            out.println(String.format(indent + "%1$s %2$s = %3$s;", json.element(), varName,
                                      jsonValueExpression(getRawClass(paramType), valueAccess)));
        }
    }

    private void generateEitherConversion(String indent, PrintWriter out, String varName, String valueAccess,
                                          Type paramType) {
        String innerName = varName + "e";

        out.println(indent + String.format("%1$s %2$s;", json.element(), varName));
        out.println(indent + String.format("if (%1$s.getLeft() != null) {", valueAccess));
        generateToJson(indent + INDENT, out, innerName, valueAccess + ".getLeft()", EitherUtil.getLeftDisjointType(paramType));
        out.println(indent + INDENT + String.format("%1$s= %2$s;", varName, innerName));
        out.println(indent + "} else  {");
        generateToJson(indent + INDENT, out, innerName, valueAccess + ".getRight()", EitherUtil.getRightDisjointType(paramType));
        out.println(indent + INDENT + String.format("%1$s= %2$s;", varName, innerName));
        out.println(indent + "}");
    }

    private void generateMapConversion(String indent, PrintWriter out, String varName, String valueAccess,
                                       Type paramType) {
        ParameterizedType genericType = (ParameterizedType)paramType;
        Type valueType = genericType.getActualTypeArguments()[1];
        String containedName = varName + "X";
        out.println(String.format(indent + "%1$s %2$s = new %1$s();", json.object(), varName));
        out.println(String.format(indent + "for (Entry<String, %1$s> %2$s : %3$s.entrySet()) {",
                                  valueType.getTypeName(), containedName, valueAccess));
        generateToJson(indent + INDENT, out, varName + "Y", containedName + ".getValue()", valueType);
        out.println(indent + INDENT + String.format("%1$s.%2$s(%3$s.getKey().toString(), %4$s);", varName, json.put(),
                                                    containedName, varName + "Y"));
        out.println(indent + "}");

    }

    private String jsonValueExpression(Class<?> paramType, String valueAccess) {
        if (paramType.isPrimitive()) {
            return String.format("%1$s;", toJsonConversion(paramType, valueAccess));
        } else {
            return String.format("%1$s == null ? %2$s : %3$s;", valueAccess, json.nullValue(),
                                 toJsonConversion(paramType, valueAccess));
        }
    }

    private String toJsonConversion(Class<?> t, String value) {
        if (Enum.class.isAssignableFrom(t)) {
            return String.format("new %1$s(%2$s.name())", json.string(), value);
        } else if (String.class.isAssignableFrom(t)) {
            return String.format("new %1$s(%2$s)", json.string(), value);
        } else if (Number.class.isAssignableFrom(t)) {
            return String.format("new %1$s(%2$s.doubleValue())", json.number(), value);
        } else if (t == boolean.class || Boolean.class.isAssignableFrom(t)) {
            return json.boolValue(value);
        } else if (isSimpleNumberType(t)) {
            return String.format("new %1$s(%2$s)", json.number(), value);
        } else if (t == Object.class) {
            return String.format("JsonUtil.convertToJson(%1$s)", value);
        } else {
            return String.format("((%2$s)%1$s).toJsonElement()", value, dtoName(t));
        }
    }

    private class ListConverter {
        private String varName;
        private String valueAccess;
        private Type   paramType;

        public ListConverter(String varName, String valueAccess,
                             Type paramType) {
            this.varName = varName;
            this.valueAccess = valueAccess;
            this.paramType = paramType;
        }

        private void generateListConversion(String indent, PrintWriter out) {
            Type containedType = containedType(paramType);

            String containedName = varName + "X";
            out.println(String.format(indent + "%1$s %2$s = new %1$s();", json.array(), varName));
            out.println(String.format(indent + "for (%1$s %2$s : %3$s) {", containedType.getTypeName(), containedName,
                                      valueAccess));
            generateToJson(indent + INDENT, out, varName + "Y", containedName, containedType);
            out.println(indent + INDENT + json.add(varName, varName + "Y"));
            out.println(indent + "}");
        }
    }

}