Updating code example

xxx-read-file-improvements/data.csv

@@ -1,10 +1,2 @@
-Reporting Period,Project Number,Legacy Project Number,City,,,,,,,,,,
-6/30/21,305,01001-00048,Babylon,,,,,,,,,,
-6/30/21,2011-188607-SLPR,,Syosset,,,,,,,,,,
-6/30/21,2011-157262-SLPR,,Bellport,,,,,,,,,,
-6/30/21,256419,,Queens,,,,,,,,,,
-5/30/21,2014-655036-Sola,,Babylon,,,,,,,,,,
-5/30/21,310687,,Babylon,,,,,,,,,,
-5/30/21,2014-648451-Sola,,Centereach,,,,,,,,,,
-5/30/21,2011-157191-SLPR,,Water Mill,,,,,,,,,,
-4/30/21,2013-636596-Sola,,Farmingdale,,,,,,,,,,
+Reporting Period,Project Number,Legacy Project Number,City,County,State,Zip Code,Sector,Program Type,Solicitation,Electric Utility,Purchase Type,Date Application Received,Date Completed,Project Status,Contractor,Primary Inverter Manufacturer,Primary Inverter Model Number,Total Inverter Quantity,Primary PV Module Manufacturer,PV Module Model Number,Total PV Module Quantity,Project Cost,$Incentive,Total Nameplate kW DC,Expected KWh Annual Production,Remote Net Metering,Affordable Solar,Community Distributed Generation,Green Jobs Green New York Participant,Georeference
+06/30/2021,0000000305,01001-00048,Williamson,Wayne,NY,14589,Non-Residential,Residential/Small Commercial,PON 1184,,,08/03/2003,06/23/2005,Complete,"Solar Works, Inc.",Fronius USA,IG 2500-LV,1,BP Solar,BP3125S,16,,,2.00,,,No,No,No,POINT (-77.175308 43.241518)

xxx-read-file-improvements/script.txt

@@ -1,9 +1,13 @@
 Hey Java developers,
 
-Reading files is difficult?
+Finding your self getting lost in a max of if statements and for loops when processing large files?
 
-Make it easier!
+[Where am I?!]
 
+Try using streams instead
 
+Stream, added in Java 8, and updated since then, provide many benefits when performing complex processing of large data sets
+
+In this example, to group, order, pr
 
 Happy coding!

xxx-read-file-improvements/src/main/java/ElectricProject.java

@@ -0,0 +1,44 @@
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.time.Month;
+import java.time.format.DateTimeFormatter;
+
+public record ElectricProject(LocalDate reportingPeriod, String projectNumber, String legacyProjectNumber, String city,
+ String county, String state, String zipCode, String sector, String programType, String solicitation,
+ String electricUtility, String purchaseType, LocalDate dateApplicationReceived, LocalDate dateCompleted,
+ String projectStatus, String contractor, String primaryInverterManufacturer, String primaryInverterModelNumber,
+ BigDecimal totalInverterQuantity, String primaryPVModuleManufacturer, String pvModuleModelNumber,
+ BigDecimal totalPVModuleQuantity, BigDecimal projectCost, BigDecimal incentive, BigDecimal totalNameplatekWDC,
+ BigDecimal expectedKWhAnnualProduction, String remoteNetMetering, String affordableSolar,
+ String communityDistributed, String generationGreenJobsGreenNewYorkParticipant, String georeference) {
+
+ static DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/yyyy");
+ boolean reportingPeriodMatches(Month month) {
+ return this.reportingPeriod.getMonth().equals(month);
+ }
+
+ static BigDecimal handleNumeric(String value) {
+ try {
+ return new BigDecimal(value);
+ } catch (Exception e) {
+ return BigDecimal.valueOf(0);
+ }
+ }
+
+ static LocalDate handleDate(String value) {
+ if (value.isBlank()) {
+ return null;
+ } else {
+ return LocalDate.parse(value, formatter);
+ }
+ }
+
+ static ElectricProject map(String[] values) {
+ return new ElectricProject(handleDate(values[0]), values[1], values[2], values[3], values[4], values[5],
+ values[6], values[7], values[8], values[9], values[10], values[11], handleDate(values[12]),
+ handleDate(values[13]), values[14], values[15], values[16], values[17], handleNumeric(values[18]),
+ values[19], values[20], handleNumeric(values[21]), handleNumeric(values[22]), handleNumeric(values[23]),
+ handleNumeric(values[24]), handleNumeric(values[25]), values[26], values[27], values[28], values[29],
+ values[30]);
+ }
+}

xxx-read-file-improvements/src/main/java/FileReaderI.java

@@ -5,39 +5,52 @@
 import java.time.LocalDate;
 import java.time.Month;
 import java.time.format.DateTimeFormatter;
-import java.util.ArrayList;
-import java.util.List;
+import java.util.SortedMap;
+import java.util.TreeMap;
 
 public class FileReaderI {
  public static void main(String[] args) {
-
- record Project(LocalDate reportingPeriod, String projectNumber, String legacyProjectNumber, String city) {
- }
- List<Project> projectsList = new ArrayList<>();
- String filename = args[0];
+ DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/yyyy");
  Month currentMonth = Month.JUNE;
-
-
+ SortedMap<String, ElectricProject> projectsByCity = new TreeMap<>();
+ String filename = args[0];
+
  try (BufferedReader br = new BufferedReader(new FileReader(new File(filename)))) {
  String line = br.readLine();
- 
+
  while (line != null) {
  if (!line.startsWith("Reporting Period")) {
  String[] values = line.split(",");
- Project project = new Project(LocalDate.parse(values[0], DateTimeFormatter.ofPattern("M/dd/yy")),
- values[1], values[2], values[3]);
- if(project.reportingPeriod.getMonth().equals(currentMonth)) {
- projectsList.add(project);
- } else {
- break;
+ if (LocalDate.parse(values[0], formatter).getMonth().equals(currentMonth)) {
+ try {
+ ElectricProject project = ElectricProject.map(values);
+ if (!projectsByCity.containsKey(project.city())) {
+ projectsByCity.put(project.city(), project);
+ } else {
+ ElectricProject existingProject = projectsByCity.get(project.city());
+ if (project.expectedKWhAnnualProduction()
+ .compareTo(existingProject.expectedKWhAnnualProduction()) > 0) {
+ projectsByCity.put(project.city(), project);
+ }
+ }
+ } catch (Exception e) {
+ // Do some cool stuff to handle errors
+ }
  }
  }
  line = br.readLine();
  }
  } catch (IOException e) {
  e.printStackTrace();
  }
-
- System.out.println(projectsList.size());
+
+ for (ElectricProject project : projectsByCity.values()) {
+ System.out.println("""
+ City: %s
+ Project Number: %s
+ Expected Output: %s
+ """.formatted(project.city(), project.projectNumber(),
+ project.expectedKWhAnnualProduction().toString()));
+ }
  }
 }

xxx-read-file-improvements/src/main/java/FileReaderII.java

@@ -4,42 +4,56 @@
 import java.time.LocalDate;
 import java.time.Month;
 import java.time.format.DateTimeFormatter;
-import java.util.List;
-import java.util.function.Function;
+import java.util.TreeMap;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 public class FileReaderII {
  public static void main(String[] args) {
-
- record Project(LocalDate reportingPeriod, String projectNumber, String legacyProjectNumber, String city) {
- }
- List<Project> projectsList = null;
- String filename = args[0];
+ DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/yyyy");
  Month currentMonth = Month.JUNE;
+ String filename = args[0];
 
- Function<String, Stream<Project>> flatMapper = line -> {
+ BiConsumer<String, Consumer<ElectricProject>> retrieveResultsForCurrentMonth = (line, consumer) -> {
  String[] values = line.split(",");
- Project project = new Project(LocalDate.parse(values[0], DateTimeFormatter.ofPattern("M/dd/yy")), values[1],
- values[2], values[3]);
- return Stream.of(project);
+ if (LocalDate.parse(values[0], formatter).getMonth().equals(currentMonth)) {
+ try {
+ consumer.accept(ElectricProject.map(values));
+ } catch (Exception e) {
+ // Do some cool stuff to handle errors
+ }
+ }
  };
 
- Predicate<String> titleLinePredicate = line -> {
- return !line.startsWith("Reporting Period");
+ Consumer<ElectricProject> printResults = project -> {
+ System.out.println("""
+ City: %s
+ Project Number: %s
+ Expected Output: %s
+ """.formatted(project.city(), project.projectNumber(),
+ project.expectedKWhAnnualProduction().toString()));
  };
 
- Predicate<Project> thisMonth = project -> {
- return project.reportingPeriod.getMonth().equals(currentMonth);
+ Predicate<String> isTitleLine = line -> line.startsWith("Reporting Period");
+
+ BinaryOperator<ElectricProject> findBestProducingProject = (newProject, currentProject) -> {
+ if (newProject.expectedKWhAnnualProduction().compareTo(currentProject.expectedKWhAnnualProduction()) > 0) {
+ return newProject;
+ } else {
+ return currentProject;
+ }
  };
 
  try (Stream<String> lines = Files.lines(Path.of(filename))) {
- projectsList = lines.filter(titleLinePredicate).flatMap(flatMapper).takeWhile(thisMonth).toList();
+ lines.filter(isTitleLine.negate()).mapMulti(retrieveResultsForCurrentMonth) //
+ .collect(Collectors.toMap(ElectricProject::city, p -> p, findBestProducingProject, TreeMap::new))
+ .values().stream().forEach(printResults);
  } catch (IOException e) {
  e.printStackTrace();
  }
-
- System.out.println(projectsList.size());
  }
-
 }