added sales analysis exercise

src/main/java/com/levelup/java/exercises/beginner/SalesAnalysis.java

@@ -0,0 +1,77 @@
+package com.levelup.java.exercises.beginner;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.DoubleSummaryStatistics;
+import java.util.List;
+
+/**
+ * This java exercises will demonstrate how to find statistics on sales
+ * information.
+ * 
+ * @author Justin Musgrove
+ * @see <a href=
+ *      'http://www.leveluplunch.com/java/exercises/sales-analysis-data/'>Sales
+ *      analysis data</a>
+ * 
+ */
+public class SalesAnalysis {
+
+	public static void main(String[] args) throws IOException {
+
+		Path salesDataPath = Paths
+				.get("src/main/resources/com/levelup/java/exercises/beginner/SalesData.txt")
+				.toAbsolutePath();
+
+		//read all lines into a list of strings 
+		List<String> fileByLines = java.nio.file.Files
+				.readAllLines(salesDataPath);
+
+		//convert each string into a DoubleSummaryStatistics object
+		List<DoubleSummaryStatistics> weeksSummary = new ArrayList<>();
+		for (String row : fileByLines) {
+			// split on comma, map to double
+			weeksSummary.add(Arrays.stream(row.split(","))
+					.mapToDouble(Double::valueOf).summaryStatistics());
+		}
+
+		displayWeeklyStats(weeksSummary);
+		displaySummaryResults(weeksSummary);
+
+	}
+
+	public static void displayWeeklyStats(
+			List<DoubleSummaryStatistics> weeksSummary) {
+
+		for (int x = 0; x < weeksSummary.size(); x++) {
+			DoubleSummaryStatistics weekStat = weeksSummary.get(x);
+
+			System.out.println("Week #" + x + " sales: $" + weekStat.getSum());
+			System.out.println("Average daily sales for week #" + x + ": $"
+					+ weekStat.getAverage());
+		}
+	}
+
+	public static void displaySummaryResults(
+			List<DoubleSummaryStatistics> weeksSummary) {
+
+		System.out.println("Total sales for all weeks: $"
+				+ weeksSummary.stream().mapToDouble(p -> p.getSum()).sum());
+
+		System.out.println("Average weekly sales: $"
+				+ weeksSummary.stream().mapToDouble(p -> p.getSum()).average()
+						.getAsDouble());
+
+		System.out.println("The highest sales was $"
+				+ weeksSummary.stream().mapToDouble(p -> p.getSum()).max()
+						.getAsDouble());
+
+		System.out.println("The lowest sales were made during "
+				+ weeksSummary.stream().mapToDouble(p -> p.getSum()).min()
+						.getAsDouble());
+
+	}
+}

src/main/resources/com/levelup/java/exercises/beginner/SalesData.txt

@@ -0,0 +1,3 @@
+1245.67,1490.07,1679.87,2371.46,1783.92,1461.99,2059.77
+2541.36,2965.88,1965.32,1845.23,7021.11,9652.74,1469.36
+2513.45,1963.22,1568.35,1966.35,1893.25,1025.36,1128.36