package de.dfki.km.json;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.List;
import java.util.Map;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonLocation;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;
/**
* A bunch of functions to make loading JSON easy
*
* @author tristan
*
*/
public class JSONUtils {
public static Object fromString(String jsonString) throws JsonParseException, JsonMappingException {
ObjectMapper objectMapper = new ObjectMapper();
Object rval = null;
if (jsonString.trim().startsWith("[")) {
try {
rval = objectMapper.readValue(jsonString, List.class);
} catch (IOException e) {
// TODO: what?
if (e instanceof JsonParseException) {
throw (JsonParseException) e;
} else if (e instanceof JsonMappingException) {
throw (JsonMappingException) e;
} else {
// TODO: Auto-generated catch block
e.printStackTrace();
}
}
} else if (jsonString.trim().startsWith("{")) {
try {
rval = objectMapper.readValue(jsonString, Map.class);
} catch (IOException e) {
if (e instanceof JsonParseException) {
throw (JsonParseException) e;
} else if (e instanceof JsonMappingException) {
throw (JsonMappingException) e;
} else {
// TODO: Auto-generated catch block
e.printStackTrace();
}
}
} else if (jsonString.trim().startsWith("\"")) {
try {
rval = objectMapper.readValue(jsonString, String.class);
} catch (IOException e) {
if (e instanceof JsonParseException) {
throw (JsonParseException) e;
} else if (e instanceof JsonMappingException) {
throw (JsonMappingException) e;
} else {
// TODO: Auto-generated catch block
e.printStackTrace();
}
}
} else if (jsonString.trim().equals("true") || (jsonString.trim().equals("false"))) {
try {
rval = objectMapper.readValue(jsonString, Boolean.class);
} catch (IOException e) {
if (e instanceof JsonParseException) {
throw (JsonParseException) e;
} else if (e instanceof JsonMappingException) {
throw (JsonMappingException) e;
} else {
// TODO: Auto-generated catch block
e.printStackTrace();
}
}
} else if (jsonString.trim().matches("[0-9.e+-]+")) {
try {
rval = objectMapper.readValue(jsonString, Number.class);
} catch (IOException e) {
if (e instanceof JsonParseException) {
throw (JsonParseException) e;
} else if (e instanceof JsonMappingException) {
throw (JsonMappingException) e;
} else {
// TODO: Auto-generated catch block
e.printStackTrace();
}
}
} else if (jsonString.trim().equals("null")) {
rval = null;
} else {
throw new JsonParseException("document doesn't start with a valid json element", new JsonLocation("\""
+ jsonString.substring(0, Math.min(jsonString.length(), 100)) + "...\"", 0, 1, 0));
}
return rval;
}
public static Object fromReader(Reader r) throws IOException {
StringBuffer sb = new StringBuffer();
int b;
while ((b = r.read()) != -1) {
sb.append((char) b);
}
return fromString(sb.toString());
}
public static void write(Writer w, Object jsonObject) throws JsonGenerationException, JsonMappingException, IOException {
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.getJsonFactory().disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
objectMapper.writeValue(w, jsonObject);
}
public static void writePrettyPrint(Writer w, Object jsonObject) throws JsonGenerationException, JsonMappingException, IOException {
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.getJsonFactory().disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
ObjectWriter objectWriter = objectMapper.writerWithDefaultPrettyPrinter();
objectWriter.writeValue(w, jsonObject);
}
public static Object fromInputStream(InputStream content) throws IOException {
return fromInputStream(content, "UTF-8"); // no readers from
// inputstreams w.o.
// encoding!!
}
public static Object fromInputStream(InputStream content, String enc) throws IOException {
return fromReader(new BufferedReader(new InputStreamReader(content, enc)));
}
public static String toPrettyString(Object obj) {
StringWriter sw = new StringWriter();
try {
writePrettyPrint(sw, obj);
} catch (Exception e) {
// TODO Is this really possible with stringwriter?
// I think it's only there because of the interface
// however, if so... well, we have to do something!
// it seems weird for toString to throw an IOException
}
return sw.toString();
}
public static String toString(Object obj) { // throws
// JsonGenerationException,
// JsonMappingException {
StringWriter sw = new StringWriter();
try {
write(sw, obj);
} catch (Exception e) {
// TODO Is this really possible with stringwriter?
// I think it's only there because of the interface
// however, if so... well, we have to do something!
// it seems weird for toString to throw an IOException
}
return sw.toString();
}
public static boolean equals(Object v1, Object v2) {
boolean rval = true;
// TODO Auto-generated method stub
if (v1 instanceof List && v2 instanceof List) {
if (((List) v1).size() != ((List) v2).size()) {
rval = false;
} else {
// TODO: should the order of things in the list matter?
for (int i = 0; i < ((List<Object>) v1).size() && rval == true; i++) {
rval = equals(((List<Object>) v1).get(i), ((List<Object>) v2).get(i));
}
}
} else if (v1 instanceof Number && v2 instanceof Number) {
// TODO: this is VERY sketchy
double n1 = ((Number) v1).doubleValue();
double n2 = ((Number) v2).doubleValue();
rval = n1 == n2;
} else if (v1 instanceof String && v2 instanceof String) {
rval = ((String) v1).equals((String) v2);
} else if (v1 instanceof Map && v2 instanceof Map) {
if (((Map) v1).size() != ((Map) v2).size()) {
rval = false;
} else {
for (Object k1 : ((Map) v1).keySet()) {
rval = ((Map) v2).containsKey(k1) ? equals(((Map) v1).get(k1), ((Map) v2).get(k1)) : false;
if (rval != true) {
break;
}
}
}
} else if (v1 instanceof Boolean && v2 instanceof Boolean) {
rval = v1 == v2;
} else if (v1 != null && v2 != null) {
rval = v1.equals(v2);
} else {
rval = v1 == v2;
}
return rval;
}
}