From 4821aa8f27d3a35af234346c2f456cb20ab2956c Mon Sep 17 00:00:00 2001
From: Christopher Bohn <bohn@unl.edu>
Date: Tue, 19 Nov 2019 11:29:08 -0600
Subject: [PATCH] Added reader that returns List, for preserving row order
---
.../edu/unl/cse/csv_io/CSVReaderWriter.java | 63 ++++++++-----------
src/main/resources/csv/demo.csv | 1 +
2 files changed, 27 insertions(+), 37 deletions(-)
diff --git a/src/main/java/edu/unl/cse/csv_io/CSVReaderWriter.java b/src/main/java/edu/unl/cse/csv_io/CSVReaderWriter.java
index 29d1ec0..6541434 100644
--- a/src/main/java/edu/unl/cse/csv_io/CSVReaderWriter.java
+++ b/src/main/java/edu/unl/cse/csv_io/CSVReaderWriter.java
@@ -12,6 +12,7 @@ import java.io.*;
import java.net.URL;
import java.util.*;
+@SuppressWarnings("unused")
public class CSVReaderWriter {
@SuppressWarnings("WeakerAccess")
public static Set<Map<String, String>> readCSVasSet(String filename) {
@@ -32,6 +33,24 @@ public class CSVReaderWriter {
return csvSet;
}
+ public static List<Map<String, String>> readCSVasList(String filename) {
+ List<Map<String, String>> csvList = null;
+ try (InputStreamReader inputStreamReader = new InputStreamReader(Objects.requireNonNull(
+ CSVReaderWriter.class.getClassLoader().getResourceAsStream("csv/" + filename)))) {
+ csvList = (List<Map<String, String>>) parseCSV(inputStreamReader, new LinkedList<>());
+ } catch (NullPointerException nullPointerException) {
+ System.err.println("Check spelling of file " + filename + ".");
+ System.exit(1);
+ } catch (IOException ioException) {
+ System.err.println("Error loading " + filename + ". " + ioException);
+ System.exit(1);
+ } catch (CsvValidationException csvValidationException) {
+ System.err.println("Could not validate a line in " + filename + ". " + csvValidationException);
+ System.exit(1);
+ }
+ return csvList;
+ }
+
private static Collection<Map<String, String>> parseCSV(InputStreamReader inputStreamReader,
Collection<Map<String, String>> destination)
throws IOException, CsvValidationException {
@@ -48,7 +67,6 @@ public class CSVReaderWriter {
}
/* LEGACY METHODS */
- @SuppressWarnings("WeakerAccess")
public static Set<Map<String, String>> readCSV(String filename) {
return readCSVasSet(filename);
}
@@ -65,6 +83,8 @@ public class CSVReaderWriter {
}
*/
+ // I'd like to replace this with something that uses openCSV, but it works, and openCSV doesn't seem to have
+ // writers that take map<string,string>
public static boolean writeCSV(String filename, Set<Map<String, String>> data) {
boolean wroteFile = true;
ClassLoader classLoader = CSVReaderWriter.class.getClassLoader();
@@ -147,42 +167,11 @@ public class CSVReaderWriter {
}
}
}
-
- /*
- public static void main(String[] args) {
- Set<Map<String, String>> demo = readCSV("demo.csv");
- boolean success = writeCSV("out.csv", demo);
- System.out.println(success ? "Wrote file!" : "Didn't write file");
- }
- */
/*
- public static void main(String[] args) {
- Set<Map<String,String>> students = readCSV("students.csv");
- for (Map<String,String> student: students) {
- System.out.println(student.get("Name"));
- }
- }
-*//*
- public static void main(String[] args) {
- Set<Map<String, String>> courses = readCSV("courses.csv");
- for (Map<String, String> course : courses) {
- String foo = course.get("URL");
- if (foo == null) {
- foo = "Null object";
- } else if (foo.equals("")) foo = "Empty String";
- System.out.println(course.get("CourseID") + " " + course.get("Section") + " " + foo + " " + course.get(
- "Prerequisite1"));
- }
- }*/
- public static void main(String[] args) {
- Set<Map<String, String>> courses = readCSV("empty.csv");
- for (Map<String, String> course : courses) {
- String foo = course.get("URL");
- if (foo == null) {
- foo = "Null object";
- } else if (foo.equals("")) foo = "Empty String";
- System.out.println(course.get("CourseID") + " " + course.get("Section") + " " + foo + " " + course.get(
- "Prerequisite1"));
- }
+ public static void main(String[] args) {
+ Set<Map<String, String>> demo = readCSV("demo.csv");
+ boolean success = writeCSV("out.csv", demo);
+ System.out.println(success ? "Wrote file!" : "Didn't write file");
}
+ */
}
diff --git a/src/main/resources/csv/demo.csv b/src/main/resources/csv/demo.csv
index 8e1318e..c0e8085 100644
--- a/src/main/resources/csv/demo.csv
+++ b/src/main/resources/csv/demo.csv
@@ -1,4 +1,5 @@
A,B,C,D
+larry,curly,moe,
one,two,,three
four,,five,six
7,8,9,
--
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