Lab 03 - Parsing Tweets with the String class Introduction Twitter and similar micro-blogging platforms allow users to broadcast short messages to a potentially large audience. With Twitter, the messages are called \"tweets\" and consist of 140 characters or less. Tweets are often sent from mobile phones, and tweeters can choose whether their tweets are public or not. The platforms allow people to communicate in ways that were not possible even a few years ago, and they have already had a profound effect on society. They even affect how society reacts to natural and manmade disastersordinary citizens can now broadcast timely and location specific information that is of vital importance to both emergency management agencies and members of the public. Sifting through the tweets for useful information is difficult, however. As a result, there have been proposals to manually add structure to tweets sent during disasters. One proposal is called Tweak the Tweet (TtT).1 In TtT, information is marked using a \"hashtag\" such as #loc (for location): MT @carlseelye: #lovelandfire #Wind just switched and now the smoke is thick around our house #loc 40.352,-105.2045 Adding the structure makes it far easier for a computer to classify the tweets. In this lab, you will use methods of the String class to process messages similar to TtT tweets (the data is made from real TtT data but it has been altered to suit the lab). You will use the substring and other methods to pull out information from the text, manipulate it, and print it out to the screen. Lab Objectives By the end of the lab, you should: understand how String constants and String objects are represented in Java; be able to declare, initialize, and assign variables of type String; perform string processing using the methods of the String class; concatenate strings (and other values) together using the '+' operator. Prerequisites The lab deals with material from Chapter 2 (specifically, the discussions of the String class). It assumes you know how define simple classes in Java, and that you can declare and assign values to variables. What to Submit You will create a single source file (ParseTheTweet.java), and it should be submitted to eLC for grading. Exercise - Parsing Tweets The class ParseTheTweet will read in a single tweet from the keyboard, and so when writing your program, you will need to use the Scanner class in addition to the String class. As usual, almost everything you write will go in the main method of the ParseTheTweet class. The tweets processed by the call all encode the following information using so-called \"hashtags\": The report type (#typ); some further detail (#det); a location (#loc) such as a street address; and latitude (#lat) and longitude (#lng). The type indicates the meaning of the tweet (i.e., whether it is a request for help or reports factual information), and the report detail provides additional information. Each of the hashtags is followed by some value (such as an actual latitude or longitude value). When writing your code, you can assume that all of the tweets to process have the following format: #typ value; #det value; #loc value; #lat value; #lng value; That is, they consist of a series of hashtags, each followed by a value, and each value followed by a semicolon (;). 9 sample tweets are provided at the end of this document. You should test your code on them. Instructions 1. At the top of your source file, include a comment stating your Java class name, your name, the date, the program purpose, and containing the statement of academic honesty as you did in previous labs. 2. Add an import statement for the Scanner class: import java.util.Scanner; 3. Create an instance of the Scanner class called theScanner. It should read from System.in. 4. Declare a String variable called tweet and initialize it to the empty string "". This will hold the tweet entered by the user. 5. Declare variables to store the information from the tweet. The variables should have the names and data types shown. o type: String o detail: String o location: String o latitudeString: String o longitudeString: String o latitude: double o longitude: double 6. Use the theScanner object to read in an entire line of text (the whole tweet) and assign the value to tweet. Since you want the whole line, you should use the nextLine()method. HINT: For testing purposes, it might be better to use a single (fixed) String constant assigned to temp, rather than use theScanner to read in a new value every time. After you've been able to successfully parse this hard coded value, go back and insert the code to read values from the theScanner. https://www.coursehero.com/file/9219196/Lab03/ This study resource was shared via CourseHero.com CSCI 1301: Lab 3 Page 3 7. Declare int values start and finish (these will store start and end indexes for substrings). 8. Use the indexOf()method of tweet to find the starting index of the substring "#typ". Add 5 to the index and assign the result to start. This will record the start of the tweet's type value. 9. Again use the indexOf()method of the tweet object to find the index of the first semicolon ";". Assign the value to finish. This will give you the ending index of the tweet's type value. 10. Use the substring method of the tweet object to find the substring demarcated by indexes start and finish. Assign this string to type. 11. Use the trim() method to remove leading and trailing white spaces (if any) from the value of type, and assign the result to type. 12. Now use the substring method to extract the substring of tweet beginning at index finish+1. Assign the result to tweet. This is tantamount to deleting the initial part of the tweet (the part encoding the type). The +1 eliminates a leading semicolon that would otherwise be included. 13. Repeat steps 8-12 to obtain values for detail, location, latitudeString, and longitudeString. HINT: It might be sufficient to copy and paste your code, replacing the variable names. 14. To obtain numerical values for the latitude and longitude, we will use theScanner again. Here, however, we don't want to read from the keyboard. Instead, we want to read directly from the strings latitudeString and longitudeString. To do this, include the statement theScanner = new Scanner(latitudeString); in your program (after all the other code you have written). 15. Afterwards, use the theScanner object's nextDouble() method to read in a floating-point value from latitudeString. Assign this value to latitude. 16. Repeat steps 14-15 to obtain the floating-point value for longitude. 17. The type values come from a very small set of values, and we want to make them all caps. To do this, use the toUpperCase method of the String class (and assign the result to type). 18. We also want to ensure that the detail and location values are free of commas (which might pose an obstacle to further processing). Use the replace method of the String class to do this. Replace each comma with a single hyphen (-). 19. Now use System.out and print or println statements to produce formatted output, as shown in the included examples. HINT: Use the escape sequence \\t to include tabs as needed. https://www.coursehero.com/file/9219196/Lab03/ This study resource was shared via CourseHero.com CSCI 1301: Lab 3 Page 4 eLC Submission and Grading After you have completed and thoroughly tested ParseTheTweet.java, submit it to eLC in order to receive credit for the lab. Always double check that your submission was successful on eLC! The lab will be graded according to the following guidelines. A score between 0 and 100 will be assigned. If the source file(s) are not submitted before the specified deadline's late period ends (48 hours after the deadline), or if they do not compile, or if the submitting student has an unexcused absence for a single lab period devoted to the assignment, then a grade of 0 will be assigned. (Note: students who show up to their first lab period and personally show their lab TA that they finished and submitted the week's lab assignment AND any assigned projects may be excused from their second lab period for that week.) If the required comment for all labs describing the program and the academic honesty statement is not included at the top of the file, then 10 points will be deducted. Note: this required comment can be found in Lab 02. If a (single) source file name is incorrect, then 10 points will be deducted. The program will be evaluated using the sample tweets below and additional tweets. For each test case, the output must be correct in order to receive credit for that test case. Example Tweets Test your code with these. 1. "#typ offer; #det free essential supplies 4 evacs pets.; #loc 2323 55th st, boulder; #lat 40.022; #lng -105.226;" 2. "#typ structure; #det damaged; #loc 224 left fork road (shed) (house okay); #lat 40.029854; #lng -105.391055;" 3. "#typ wind; #det just switched, and now the smoke is thick around our house; #loc 40.352,-105.2045; #lat 40.3523; #lng -105.2045;" 4. "#typ fire; #det firefighter sees a glow; #loc sw from west coach rd toward sunshine canyon; #lat 40.0515; #lng -105.332;" 5. "#typ structure; #det damaged; #loc unknown number, by 204 gold run road; #lat 40.050904; #lng -105.373941;" 6. "#typ evac; #det overflow shltr 4 evacuees at; #loc walt clark middle school, loveland; #lat 40.383; #lng -105.113;" 7. "#typ no fire; #det activity; #loc west of the pinewood res dam; #lat 40.367; #lng -105.292;" 8. "#typ photo; #det local wild horse; #loc wild horse; #lat 40.052304; #lng -105.319374;" 9. "#typ smoke; #det its raining ash; #loc windsor, co; #lat 40.499812; #lng -105.012075;" https://www.coursehero.com/file/9219196/Lab03/ This study resource was shared via CourseHero.com CSCI 1301: Lab 3 Page 5 Sample Output Type: OFFER Detail: free essential supplies 4 evacs pets. Location: 2323 55th st- boulder Latitude: 40.022 Longitude: -105.226 Type: STRUCTURE Detail: damaged Location: 224 left fork road (shed) (house okay) Latitude: 40.029854 Longitude: -105.391055 Type: WIND Detail: just switched- and now the smoke is thick around our house Location: 40.352--105.2045 Latitude: 40.3523 Longitude: -105.2045 Type: FIRE Detail: firefighter sees a glow Location: sw from west coach rd toward sunshine canyon Latitude: 40.0515 Longitude: -105.332 Type: STRUCTURE Detail: damaged Location: unknown number- by 204 gold run road Latitude: 40.050904 Longitude: -105.373941 Type: EVAC Detail: overflow shltr 4 evacuees at Location: walt clark middle school- loveland Latitude: 40.383 Longitude: -105.113 Type: NO FIRE Detail: activity Location: west of the pinewood res dam Latitude: 40.367 Longitude: -105.292 Type: PHOTO Detail: local wild horse Location: wild horse Latitude: 40.052304 Longitude: -105.319374 Type: SMOKE Detail: its raining ash Location: windsor- co Latitude: 40.499812 Longitude: -105.012075