/*
* Geonames Solr Index - Servlet
* Copyright (C) 2011 University of Southern Queensland
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package com.googlecode.solrgeonames.server;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A Response wrapper to rendering output for the 'search' function.
*
* @author Greg Pendlebury
*/
public class JsonSearchResponse implements OpenSearchResponse {
/** Logging */
private static Logger log = LoggerFactory.getLogger(JsonSearchResponse.class);
private HttpServletRequest request;
/**
* An initialisation function giving access to the HTTP input.
*
* @param request: The incoming HTTP request
*/
@Override
public void init(HttpServletRequest request) {
this.request = request;
}
/**
* Render a valid response to a search result list.
*
* @param results: The results list to render
* @return String: The rendered output
*/
@Override
public String renderResponse(QueryResponse results) {
return "{\n"+headResponse(results)+",\n"+listResponse(results)+"\n}";
}
/**
* Render a response indicated no results were returned
*
* @return String: The rendered output
*/
@Override
public String renderEmptyResponse() {
return "{\n"+headResponse(null)+",\n\"results\": []\n}";
}
/**
* Create a response header string for the result set.
*
* @param results: The Solr results
* @return String: Header block
*/
private String headResponse(QueryResponse results) {
// Start index
String start = request.getParameter("start");
if (start == null || start.equals("")) {
start = GeoServlet.DEFAULT_START;
}
// Rows
String rows = request.getParameter("rows");
if (rows == null || rows.equals("")) {
rows = GeoServlet.DEFAULT_ROWS;
}
String inner = escape("title", "Generic Search")+",\n";
if (results == null) {
inner += escape("totalResults", "0")+",\n";
} else {
SolrDocumentList list = results.getResults();
inner += escape("totalResults", list.getNumFound())+",\n";
}
inner += escape("startIndex", start)+",\n";
inner += escape("itemsPerPage", rows)+"\n";
return "\"OpenSearchResponse\": {\n"+inner+"\n}";
}
/**
* Create a results string for the result set.
*
* @param results: The Solr results
* @return String: Results section in JSON
*/
private String listResponse(QueryResponse results) {
// Render each row
SolrDocumentList list = results.getResults();
List<String> rows = new ArrayList();
for (SolrDocument doc : list) {
rows.add(renderRow(doc));
}
String joined = join(rows, ",\n");
return "\"results\": [\n"+joined+"\n]";
}
/**
* Simple join wrapper
*
* @param list: The List of Strings to join
* @param separator: The separator to join on
* @return String: The joined list
*/
private String join(List<String> list, String separator) {
String output = "";
for (String element : list) {
// We don't need a separator before the first element
if (!output.equals("")) {
output += separator;
}
output += element;
}
return output;
}
/**
* Render a single 'row' from the result set
*
* @param doc: The Solr document to render
* @return String: The rendered document in JSON
*/
private String renderRow(SolrDocument doc) {
String output = "";
for (String key : doc.keySet()) {
// Make sure our commas are correct
if (!output.equals("")) {
output += ",\n";
}
Object object = doc.getFieldValue(key);
String value = null;
if (object instanceof String) {
value = (String) doc.getFieldValue(key);
}
if (object instanceof Integer) {
value = String.valueOf((Integer) doc.getFieldValue(key));
}
if (object instanceof Float) {
value = String.valueOf((Float) doc.getFieldValue(key));
}
if (object instanceof Long) {
value = String.valueOf((Long) doc.getFieldValue(key));
}
if (object instanceof Date) {
value = ((Date) object).toString();
}
if (object instanceof List) {
List<String> multiValue = (ArrayList<String>) object;
StringBuffer sb = new StringBuffer();
for (Iterator iterator = multiValue.iterator(); iterator
.hasNext();) {
String string = (String) iterator.next();
sb.append(string);
if (iterator.hasNext()) {
sb.append(", ");
}
}
value = sb.toString();
}
output += escape(key, value);
// When we come across the ID, add in a Geonames URI
if (key.equals("id")) {
output += ",\n"+escape("geonames_uri",
"http://sws.geonames.org/"+value+"/");
}
}
// Display string
String name = (String) doc.getFieldValue("basic_name");
String country = (String) doc.getFieldValue("country_code");
String timezone = (String) doc.getFieldValue("timezone");
String display = name+", "+country+" ("+timezone+")";
output += ",\n"+escape("display", display);
return "{\n"+output+"\n}";
}
/**
* Simple escape function to avoid typos when
* joining a key/value pair into JSON
*
* @param key: The key string
* @param value The value string
* @return String: The key value pair escape, quoted and joined
*/
private String escape(String key, long value) {
return escape(key, String.valueOf(value));
}
/**
* Simple escape function to avoid typos when
* joining a key/value pair into JSON
*
* @param key: The key string
* @param value The value string
* @return String: The key value pair escape, quoted and joined
*/
private String escape(String key, String value) {
key = key.replace("\"", "\\\"");
key = key.replace("\\", "\\\\");
if (value == null) {
value = "";
}
value = value.replace("\"", "\\\"");
value = value.replace("\\", "\\\\");
return "\""+key+"\": \""+value+"\"";
}
/**
* Render an error message response
*
* @param String: The message to include in the response
* @return String: The rendered output
*/
@Override
public String renderError(String message) {
message = message.replace("\"", "\\\"");
message = message.replace("\\", "\\\\");
return "{\"Error\": \""+message+"\"}";
}
/**
* Get the content type to return to users for this response
*
* @return String: The MIME type to use
*/
@Override
public String contentType() {
return "application/json";
}
}