org.primeframework.mvc.action.result.JSONResult.java Source code

Introduction

Here is the source code for org.primeframework.mvc.action.result.JSONResult.java

Source

/*
 * Copyright (c) 2001-2015, Inversoft Inc., All Rights Reserved
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 */
package org.primeframework.mvc.action.result;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.inject.Inject;
import org.primeframework.mvc.PrimeException;
import org.primeframework.mvc.action.ActionInvocation;
import org.primeframework.mvc.action.ActionInvocationStore;
import org.primeframework.mvc.action.config.ActionConfiguration;
import org.primeframework.mvc.action.result.annotation.JSON;
import org.primeframework.mvc.content.json.JacksonActionConfiguration;
import org.primeframework.mvc.message.*;
import org.primeframework.mvc.message.scope.MessageScope;
import org.primeframework.mvc.parameter.el.ExpressionEvaluator;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.*;

/**
 * This result writes out Java objects to JSON using Jackson. The content type is set to 'application/json'.
 *
 * @author Brian Pontarelli
 */
public class JSONResult extends AbstractResult<JSON> {
    private final ActionInvocationStore actionInvocationStore;

    private final MessageStore messageStore;

    private final ObjectMapper objectMapper;

    private final HttpServletResponse response;

    @Inject
    public JSONResult(ExpressionEvaluator expressionEvaluator, ActionInvocationStore actionInvocationStore,
            MessageStore messageStore, ObjectMapper objectMapper, HttpServletResponse response) {
        super(expressionEvaluator);
        this.messageStore = messageStore;
        this.response = response;
        this.actionInvocationStore = actionInvocationStore;
        this.objectMapper = objectMapper;
    }

    public void execute(JSON json) throws IOException, ServletException {
        ActionInvocation current = actionInvocationStore.getCurrent();
        Object action = current.action;
        if (action == null) {
            throw new PrimeException(
                    "There is no action class and somehow we got into the JSONResult code. Bad mojo!");
        }

        ActionConfiguration configuration = current.configuration;
        if (configuration == null) {
            throw new PrimeException(
                    "The action [" + action.getClass() + "] has no configuration. This should be impossible!");
        }

        // If there are error messages, put them in a well known container and render that instead of looking for the
        // @JSONResponse annotation
        Object jacksonObject;
        List<Message> messages = messageStore.get(MessageScope.REQUEST);
        if (messages.size() > 0) {
            jacksonObject = convertErrors(messages);
        } else {
            JacksonActionConfiguration jacksonActionConfiguration = (JacksonActionConfiguration) configuration.additionalConfiguration
                    .get(JacksonActionConfiguration.class);
            if (jacksonActionConfiguration == null || jacksonActionConfiguration.responseMember == null) {
                throw new PrimeException("The action [" + action.getClass()
                        + "] is missing a field annotated with @JSONResponse. This is used to figure out what to send back in the response.");
            }

            jacksonObject = expressionEvaluator.getValue(jacksonActionConfiguration.responseMember, action);
            if (jacksonObject == null) {
                throw new PrimeException("The @JSONResponse field [" + jacksonActionConfiguration.responseMember
                        + "] in the action [" + action.getClass() + "] is null. It cannot be null!");
            }
        }

        ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);
        objectMapper.writeValue(baos, jacksonObject);

        byte[] result = baos.toByteArray();
        response.setStatus(json.status());
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json");
        response.setContentLength(result.length);

        if (!isCurrentActionHeadRequest(current)) {
            ServletOutputStream outputStream = response.getOutputStream();
            outputStream.write(result);
            outputStream.flush();
        }
    }

    private ErrorMessages convertErrors(List<Message> messages) {
        ErrorMessages errorMessages = new ErrorMessages();
        for (Message message : messages) {
            if (message instanceof FieldMessage) {
                FieldMessage fieldMessage = (FieldMessage) message;
                errorMessages.addFieldError(fieldMessage.getField(), fieldMessage.getCode(),
                        fieldMessage.toString());
            } else {
                errorMessages.generalErrors.add(new ErrorMessage(message.getCode(), message.toString()));
            }
        }

        return errorMessages;
    }

}