net.anyflow.lannister.httphandler.Topics.java Source code

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Here is the source code for net.anyflow.lannister.httphandler.Topics.java

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/*
 * Copyright 2016 The Lannister Project
 * 
 * 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 net.anyflow.lannister.httphandler;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Strings;

import net.anyflow.lannister.topic.Topic;
import net.anyflow.menton.http.HttpRequestHandler;

@HttpRequestHandler.Handles(paths = { "topics" }, httpMethods = { "GET" })
public class Topics extends HttpRequestHandler {

    private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(Topics.class);

    private String allString() {
        try {
            return (new ObjectMapper()).writeValueAsString(Topic.NEXUS.map());
        } catch (JsonProcessingException e) {
            logger.error(e.getMessage(), e);
            return null;
        }
    }

    @Override
    public String service() {
        String filter = Strings.nullToEmpty(httpRequest().parameter("filter"));

        switch (filter) {
        case "":
        case "all":
            return allString();

        default:
            return null;
        }
    }
}