DebuggerActionProvider.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.api.debugger.server;

import com.google.common.io.CharStreams;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

import org.eclipse.che.api.debug.shared.dto.action.ActionDto;
import org.eclipse.che.api.debug.shared.dto.action.ResumeActionDto;
import org.eclipse.che.api.debug.shared.dto.action.StartActionDto;
import org.eclipse.che.api.debug.shared.dto.action.StepIntoActionDto;
import org.eclipse.che.api.debug.shared.dto.action.StepOutActionDto;
import org.eclipse.che.api.debug.shared.dto.action.StepOverActionDto;
import org.eclipse.che.api.debug.shared.dto.action.SuspendActionDto;
import org.eclipse.che.api.debug.shared.model.action.Action;
import org.eclipse.che.dto.server.DtoFactory;
import org.eclipse.che.dto.shared.DTO;

import javax.inject.Singleton;
import javax.ws.rs.Consumes;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.Provider;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

/**
 * Implementation of {@link MessageBodyReader} needed for binding JSON content to Java Objects.
 *
 * @author Anatoliy Bazko
 * @see DTO
 * @see DtoFactory
 */
@Singleton
@Provider
@Consumes({MediaType.APPLICATION_JSON})
public class DebuggerActionProvider implements MessageBodyReader<ActionDto> {

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return ActionDto.class.isAssignableFrom(type);
    }

    @Override
    public ActionDto readFrom(Class<ActionDto> type,
                              Type genericType,
                              Annotation[] annotations,
                              MediaType mediaType,
                              MultivaluedMap<String, String> httpHeaders,
                              InputStream entityStream) throws IOException, WebApplicationException {
        String json = CharStreams.toString(new BufferedReader(new InputStreamReader(entityStream)));

        JsonParser jsonParser = new JsonParser();
        JsonElement jsonElement = jsonParser.parse(json);
        JsonObject jsonObject = jsonElement.getAsJsonObject();


        if (!jsonObject.has("type")) {
            throw new IOException("Json is broken. There is not type key in json object");
        }

        Action.TYPE actionType = Action.TYPE.valueOf(jsonObject.get("type").getAsString());
        switch (actionType) {
            case RESUME:
                return DtoFactory.getInstance().createDtoFromJson(json, ResumeActionDto.class);
            case START:
                return DtoFactory.getInstance().createDtoFromJson(json, StartActionDto.class);
            case STEP_INTO:
                return DtoFactory.getInstance().createDtoFromJson(json, StepIntoActionDto.class);
            case STEP_OUT:
                return DtoFactory.getInstance().createDtoFromJson(json, StepOutActionDto.class);
            case STEP_OVER:
                return DtoFactory.getInstance().createDtoFromJson(json, StepOverActionDto.class);
            case SUSPEND:
                return DtoFactory.getInstance().createDtoFromJson(json, SuspendActionDto.class);
            default:
                throw new IOException("Can't parse json. Unknown action type: "  + actionType);
        }
    }

}