A Java library for the Forecast.io API. It is quite functional at this point. It still does not fully implements the API but it handles most of the data and I intended to continue further development. Code is available as an Eclipse project. A jar file is available under the jar folder for convenience.

Java 1.7
Tested under Windows 7 64bits, Linux Mint 15 and Ubuntu 13.04 64bits, but it should run everywhere.

####Update (15-12-2013):

• Alerts are now supported.
• Errors are now supported.
• New properties in DataPoints are now supported.
• The URL is now constructed with StringBulder().
• Improved the internal httpGET method and it should not return truncated responses anymore. ( Suggestion by DragiPandeliev )
• The request is now has Accept-Encoding: gzip added to the header, acording with the heartly recommendation of Forecast.io documentation.
• Improved flags class.
• Other code improvements.

####Update (29-06-2013):

• Return null if the field is not defined rather than -1d where -1 might be an accurate value.( Contribution by matthew-cox )

####Update (27-06-2013):

• Fixed bug in timeURL in the internal url builder. ( Contribution by matthew-cox )
• Fixed some typos in the README.md

####Update (22-06-2013):

• Thanks to a contribution by brobzilla, ForecastIO-Lib-Java can be used with an external HTTP library. The request URL can be obtained by the getUrl method in the ForecastIO class. The ForecastIO method getForecast can now also be called with a JsonObject or with a String as parameter. Check the "Usage Examples" bellow to see how to use an external HTTP library.
• Better error handling while using the internal HTTP method.

####What is does:

• It can read Data Points and Data blocks from the Forecast.io API.
  • This means it can read Currently, Minutely, Hourly and Daily data.
• It reads all available fields.
• It reads all the available flags except one - metno-license.
• It reads all the available alerts.
• It reads all the available errors.

####What it does not:

• It does not read alerts and errors (the confidence in the prediction provided by the API). Already implemented.
• It does not implements the callback request option. Did not seamed relevant for this.

####To Do:

• Improve time zone support Kind of done.
• Add support to errors (confidence in prediction) Done.
• Add support to alerts Done.
• (maybe) Add the ability to export data to CSV
• (maybe) Add the ability of converting units of received data: (This would make sense if there were the need of displaying data in various units without having to make multiple queries.)

####How it works: The ForecastIO-Lib-Java currently has 9 classes (I'll probably add two more to deal with errors). The main class is ForecastIO: It handles the connection the gets the initial data from the API. The classes FIOCurrently, FIOMinutely, FIOHourly, FIODaily, FIOFlags and FIOAlerts contain the currently, minutely, hourly, daily, flags and alerts reports. The classes FIODataPoint, FIODataBlock handle the data in the previous reports (except for the flags). Most of the work is done by the FIODataPoint class.

Please refer to the API docs https://developer.forecast.io for better understanding of the data and for the APY key. - You'll need a key to get it to work.

####External Libraries:

• minimal-json ForecastIO-Lib-Java uses the minimal-json for parsing the Json API response. I find this library to be great... This in not a dependency because I added the classes to my project. [https://github.com/ralfstx/minimal-json](https://github.com/ralfstx/minimal-json
  http://eclipsesource.com/blogs/2013/04/18/minimal-json-parser-for-java/

######About the package name In case someone wonders, dme are just my initials. As there is no TLD .dme I decided to use them for the package.

To use it add the jar file to your project build path or add the classes from dme.forecastiolib and com.eclipse.json ( minimal-json )

Data is initialized and fetched by the ForecastIO class:

ForecastIO fio = new ForecastIO(your_api_key); //instantiate the class with the API key. 
fio.setUnits(ForecastIO.UNITS_SI);             //sets the units as SI - optional
fio.setExcludeURL("hourly,minutely");             //excluded the minutely and hourly reports from the reply
fio.getForecast("38.7252993", "-9.1500364");   //sets the latitude and longitude - not optional
                                               //it will fail to get forecast if it is not set
                                               //this method should be called after the options were set

...or using an external http library:

ForecastIO fio = new ForecastIO(your_api_key); //instantiate the class with the API key. 
fio.setUnits(ForecastIO.UNITS_SI);             //sets the units as SI - optional
fio.setExclude("hourly,minutely");             //excluded the minutely and hourly reports from the reply
String response = Some_External_Http_Library.GET(fio.getUrl("38.7252993", "-9.1500364")); //use the getUrl method to access the
                                                                                          //generated request URL.
//Parse the reply
//Option 1, (easiest):
fio.getForecast(response);
//Option 2
fio.getForecast(JsonObject.readFrom(response));

Currently, minutely, hourly, daily and flags classes are all initialized in the same way, with a ForecastIO class as an argument:

FIOMinutely minutely = new FIOMinutely(fio);

Most data is accessed like this:

currently.get().temperature(); //gets the temperature data for the currently report
daily.getDay(3).humidity();       //gets the humidity data for day 4 in the daily report

The following examples print the data available in each class.

Forecast common data:

    ForecastIO fio = new ForecastIO(your_api_key);
	fio.setUnits(ForecastIO.UNITS_SI);
	fio.getForecast("38.7252993", "-9.1500364");
	System.out.println("Latitude: "+fio.getLatitude());
	System.out.println("Longitude: "+fio.getLongitude());
	System.out.println("Timezone: "+fio.getTimezone());
	System.out.println("Offset: "+fio.getOffset());

Currently report:

    FIOCurrently currently = new FIOCurrently(fio);
    //Print currently data
	System.out.println("\nCurrently\n");
	String [] f  = currently.get().getFieldsArray();
	for(int i = 0; i<f.length;i++)
		System.out.println(f[i]+": "+currently.get().getByKey(f[i]));

Minutely report:

    FIOMinutely minutely = new FIOMinutely(fio);
    //In case there is no minutely data available
	if(minutely.minutes()<0)
		System.out.println("No minutely data.");
	else
		System.out.println("\nMinutely\n");
	//Print minutely data
	for(int i = 0; i<minutely.minutes(); i++){
		String [] m = minutely.getMinute(i).getFieldsArray();
		System.out.println("Minute #"+(i+1));
		for(int j=0; j<m.length; j++)
			System.out.println(m[j]+": "+minutely.getMinute(i).getByKey(m[j]));
	}

Hourly report:

    FIOHourly hourly = new FIOHourly(fio);
    //In case there is no hourly data available
	if(hourly.hours()<0)
		System.out.println("No hourly data.");
	else
		System.out.println("\nHourly:\n");
	//Print hourly data
	for(int i = 0; i<hourly.hours(); i++){
		String [] h = hourly.getHour(i).getFieldsArray();
		System.out.println("Hour #"+(i+1));
		for(int j=0; j<h.length; j++)
			System.out.println(h[j]+": "+hourly.getHour(i).getByKey(h[j]));
		System.out.println("\n");
	}

Daily report:

    FIODaily daily = new FIODaily(fio);
    //In case there is no daily data available
	if(daily.days()<0)
		System.out.println("No daily data.");
	else
		System.out.println("\nDaily:\n");
	//Print daily data
	for(int i = 0; i<daily.days(); i++){
		String [] h = daily.getDay(i).getFieldsArray();
		System.out.println("Day #"+(i+1));
		for(int j=0; j<h.length; j++)
			System.out.println(h[j]+": "+daily.getDay(i).getByKey(h[j]));
		System.out.println("\n");
	}

Flag report:

    FIOFlags flags = new FIOFlags(fio);
    //Print information for metar stations
	for(int i=0; i<flags.metarStations().length; i++)
		System.out.println("Metar Stations: "+flags.metarStations()[i]);
	System.out.println("\n");
	//Print all available flags
	for(int i=0; i<flags.availableFlags().length; i++)
		System.out.println(flags.availableFlags()[i]);

Alerts report:

    FIOAlerts alerts = new FIOAlerts(fio);
	//Check if there are alerts
	if(alerts.NumberOfAlerts() <= 0){
		System.out.println("No alerts for this locatoin.");
	} 
	//if there are alerts, print them.
	else {
		System.out.println("Alerts");
		for(int i=0; i<alerts.NumberOfAlerts(); i++)
			System.out.println(alerts.getAlert(i));
	}

To report issues please do it in Github or send me an email.

I generated a javadoc based in the comments I made. It is included in the files under the javadoc/ folder but do not expect it to be best documentation ever.

I started writing this library for two main reasons: First, I wanted to make a serious open source library that was meant to used by anyone and not just by me for quite sometime. Second, I came across the Forecast.io API that I found to be functional with clear and good information. Also, I like the weather and weather data and weather prediction so this is going to be very useful for me to implement my crazy ideas about weather software.

• David Ervideira

  • Initial implementation and main development

• Rob Kennedy

  • Add the possibility to use an external http library

The code is available under the terms of the Eclipse Public License.

15-12-2013