package com.taskadapter.redmineapi.internal.json;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class JsonInput {
/**
* Parses required item list.
*
* @param obj
* object to extract a list from.
* @param field
* field to parse.
* @param parser
* single item parser.
* @return parsed objects.
* @throws JSONException
* if format is invalid.
*/
public static <T> List<T> getListNotNull(JSONObject obj, String field,
JsonObjectParser<T> parser) throws JSONException {
final JSONArray items = getArrayNotNull(obj, field);
final int length = items.length();
final List<T> result = new ArrayList<T>(length);
for (int i = 0; i < length; i++)
result.add(parser.parse(items.getJSONObject(i)));
return result;
}
/**
* Parses optional item list.
*
* @param obj
* object to extract a list from.
* @param field
* field to parse.
* @param parser
* single item parser.
* @return parsed objects.
* @throws JSONException
* if format is invalid.
*/
public static <T> List<T> getListOrNull(JSONObject obj, String field,
JsonObjectParser<T> parser) throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
final JSONArray items = obj.getJSONArray(field);
final int length = items.length();
final List<T> result = new ArrayList<T>(length);
for (int i = 0; i < length; i++)
result.add(parser.parse(items.getJSONObject(i)));
return result;
}
/**
* Parses optional item list.
*
* @param obj
* object to extract a list from.
* @param field
* field to parse.
* @param parser
* single item parser.
* @return parsed objects.
* @throws JSONException
* if format is invalid.
*/
public static <T> List<T> getListOrEmpty(JSONObject obj, String field,
JsonObjectParser<T> parser) throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return new ArrayList<T>();
final JSONArray items = obj.getJSONArray(field);
if (items == null)
return new ArrayList<T>();
final int length = items.length();
final List<T> result = new ArrayList<T>(length);
for (int i = 0; i < length; i++)
result.add(parser.parse(items.getJSONObject(i)));
return result;
}
/**
* Fetch a date or null.
*
* @param obj
* object to get.
* @param field
* field to use.
* @param dateFormat
* field date format.
* @return data format.
* @throws JSONException
* if error occurs.
*/
public static Date getDateOrNull(JSONObject obj, String field,
final SimpleDateFormat dateFormat) throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
final String guess = obj.getString(field);
try {
return dateFormat.parse(guess);
} catch (ParseException e) {
throw new JSONException("Bad date value " + guess);
}
}
/**
* Fetches an optional string from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid
*/
public static String getStringOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return obj.getString(field);
}
/**
* Returns an optional "boolean" field value. If field is absent or set to
* <code>null</code>, this method returns <code>false</code>.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value for.
* @return boolean value.
* @throws JSONException
* if input is not valid (field value is not boolean).
*/
public static boolean getOptionalBool(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field)) {
return false;
}
return obj.getBoolean(field);
}
/**
* Fetches an optional string from an object. Absent value is returned as an
* empty string instead of null.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid
*/
public static String getStringOrEmpty(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return "";
return obj.getString(field);
}
/**
* Fetches a string from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static String getStringNotNull(JSONObject obj, String field)
throws JSONException {
return obj.getString(field);
}
/**
* Fetches an int from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static int getInt(JSONObject obj, String field) throws JSONException {
return obj.getInt(field);
}
/**
* Fetches an int from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @param deflt
* default value.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static int getInt(JSONObject obj, String field, int deflt)
throws JSONException {
return obj.optInt(field, deflt);
}
/**
* Fetches an optional int from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static Integer getIntOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return obj.getInt(field);
}
/**
* Fetches a long from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static long getLong(JSONObject obj, String field)
throws JSONException {
return obj.getLong(field);
}
/**
* Fetches an optional long from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static Long getLongOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return obj.getLong(field);
}
/**
* Fetches an optional float from an object.
*
* @param obj
* object to get a field from.
* @param field
* field to get a value from.
* @throws JSONException
* if value is not valid, not exists, etc...
*/
public static Float getFloatOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return (float) obj.getDouble(field);
}
/**
* Retreive optional object.
*
* @param obj
* object to parse.
* @param field
* field part.
* @param parser
* parset ojbect.
* @return parsed object.
* @throws JSONException
* if value is not valid.
*/
public static <T> T getObjectOrNull(JSONObject obj, String field,
JsonObjectParser<T> parser) throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return parser.parse(obj.getJSONObject(field));
}
/**
* Returns a json array as "not-null" value.
*
* @param obj
* object to get a value from.
* @param field
* field to get a value from.
* @return json array.
*/
public static JSONArray getArrayOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return obj.getJSONArray(field);
}
/**
* Returns a json array as "not-null" value.
*
* @param obj
* object to get a value from.
* @param field
* field to get a value from.
* @return json array.
*/
public static JSONArray getArrayNotNull(JSONObject obj, String field)
throws JSONException {
return obj.getJSONArray(field);
}
/**
* Returns a json object field for a specified object.
*
* @param obj
* object to get a field from.
* @param field
* returned field.
* @return object field.
* @throws JSONException
* if target field is not an object.
*/
public static JSONObject getObjectNotNull(JSONObject obj, String field)
throws JSONException {
return obj.getJSONObject(field);
}
/**
* Returns a json object field for a specified object.
*
* @param obj
* object to get a field from.
* @param field
* returned field.
* @return object field.
* @throws JSONException
* if target field is not an object.
*/
public static JSONObject getObjectOrNull(JSONObject obj, String field)
throws JSONException {
if (!obj.has(field) || obj.isNull(field))
return null;
return obj.getJSONObject(field);
}
}