I can a couple of classes defined by myself which are in charge of reading different shapes from different types of file (json, csv, xml) , and possibly later from a web service.
I have come up with a common interface called ShapeReader
public interface ShapeReader{
List<Shapes> readShapes() throws Exception;
}
I have a couple classes implement this interface
FlatFileReader
public class FlatFileReader implements ShapeReader{
private static final String filename = "shapes.txt";
#Override
public List<Shape> readShapes() throws Exception {
List<Shape> shapes= new ArrayList<>();
try(BufferedReader reader = new BufferedReader(new InputStreamReader(new ClassPathResource(filename).getInputStream()))) {
String line ;
while((line = reader.readLine()) != null){
// create Shape objects
);
shapes.add(shape);
}
log.info("Items read from json file: " + items);
}
catch(Exception e) {
//error handle
}
return shapes;
}
}
XmlReader
public class FlatFileReader implements ShapeReader{
private static final String filename = "shapes.xml";
#Override
public List<Shape> readShapes() throws Exception {
List<Shape> shapes= new ArrayList<>();
try(BufferedReader reader = new BufferedReader(new InputStreamReader(new ClassPathResource(filename).getInputStream()))) {
String line ;
while((line = reader.readLine()) != null){
// create Shape objects from xml
);
shapes.add(shape);
}
log.info("Items read from json file: " + items);
}
catch(Exception e) {
//error handle
}
return shapes;
}
}
I am not sure how I can even test this. I was thinking of reading from a mock test.txt file, but the filename is hardcoded as a static constant. What is the best way to solve this issue which I assume is poor design
Related
I'm looking to refactor two supplier classes as they both have very similar code. One provides and ArrayList and the other a Map. They are sorted in the configuration folder but I'm not sure thats the correct place. They both load data from a text file sorted in the project folder, which doesn't feel right to me.
The two supplier classes are:
#Component
public class ModulusWeightTableSupplier implements Supplier<List>{
private static final Logger LOGGER = LogManager.getLogger(CDLBankDetailsValidator.class);
private static final String MODULUS_WEIGHT_TABLE = "AccountModulus_Weight_Table.txt";
#Override
public List<ModulusWeightTableEntry> get(){
LOGGER.debug("Attempting to load modulus weight table " + MODULUS_WEIGHT_TABLE);
final List<ModulusWeightTableEntry> modulusWeightTable = new ArrayList<>();
try{
final InputStream in = new FileInputStream(MODULUS_WEIGHT_TABLE);
final BufferedReader br = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = br.readLine()) != null) {
final String[] fields = line.split("\\s+");
modulusWeightTable.add(new ModulusWeightTableEntry(fields));
}
LOGGER.debug("Modulus weight table loaded");
br.close();
}
catch (final IOException e) {
throw new BankDetailsValidationRuntimeException("An error occurred loading the modulus weight table or sort code substitution table", e);
}
return modulusWeightTable;
}
}
and
#Component
public class SortCodeSubstitutionTableSupplier implements Supplier<Map> {
private static final Logger LOGGER = LogManager.getLogger(CDLBankDetailsValidator.class);
private static final String SORT_CODE_SUBSTITUTION_TABLE = "SCSUBTAB.txt";
#Override
public Map<String, String> get() {
LOGGER.debug("Attempting to load sort code substitution table " + SORT_CODE_SUBSTITUTION_TABLE);
final Map<String, String> sortCodeSubstitutionTable = new HashMap<>();
try {
final InputStream in = new FileInputStream(SORT_CODE_SUBSTITUTION_TABLE);
final BufferedReader br = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = br.readLine()) != null) {
final String[] fields = line.split("\\s+");
sortCodeSubstitutionTable.put(fields[0], fields[1]);
}
LOGGER.debug("Sort code substitution table loaded");
br.close();
}
catch (final IOException e) {
throw new BankDetailsValidationRuntimeException("An error occurred loading the sort code substitution table", e);
}
return sortCodeSubstitutionTable;
}
}
Both classes have a lot of duplicate code. I'm trying to work out the best way to refactor them.
So your current code loads some configuration from textual files. Maybe best solution for this would be to go with properties or yaml files. This is most common approach for loading configuration data from external files.
Good starting point would be Spring Boot documentation for externalized configuration which provides information on how to use both properies and yaml files for loading configuration data in your application.
I can't add the file input to my map. It says I am missing something and that the Items []is not instantiated. I can't seem to figure it out
public class BigCities {
private Map<String, Set<CityItem>> countryMap;
private File file;
public BigCities(String fileName) {
countryMap = new TreeMap<>();
file = new File(fileName);
readFile(fileName);
}
private void readFile(String fileName) {
// Opg 3c implementeres her.
CityItem cityItem;
try(BufferedReader br = new BufferedReader(new FileReader(fileName))) {
StringBuilder sb = new StringBuilder();
String line = br.readLine();
String[] items;
while (line != null) {
sb.append(line);
sb.append(System.lineSeparator());
line.split(";");
line = br.readLine();
cityItem = new CityItem(items[1], items[2], items[3]);
}
String everything = sb.toString();
System.out.println(everything);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public String toString() {
return countryMap.toString();
}
/**
* #param args
*/
public static void main(String[] args) {
//Vaelg ANSI eller UTF8 afhaengig af hvad der virker bedst paa din computer:
BigCities bc = new BigCities("EuroCities ANSI.txt");
//BigCities bc = new BigCities("EuroCities UTF8.txt");
System.out.println(bc);
}
}
I Don't know what I am missing to add the input, but hopefully someone has some input.
I Am new to programming and therefore I find it confusing, since I feel like I am following all the right methods.
You never initialize the items array, so when trying to access it, you're getting null, or it may just be caught by the compiler and will give you an error there.
I suspect that you mean to assign the split to items, so change the line
line.split(";");
to
items = line.split(";");
I am able to load files in Fixed Format but unable to write a fixed format file using FixedFormat4j.
Any idea how to do that?
public class MainFormat {
public static void main(String[] args) {
new MainFormat().start();
}
private FixedFormatManager manager;
public void start(){
System.out.println("here");
manager = new FixedFormatManagerImpl();
try {
BufferedReader br = new BufferedReader(new FileReader("d:/myrecords.txt"));
System.out.println("here1");
String text;
MyRecord mr = null;
while ((text = br.readLine()) != null) {
mr = manager.load(MyRecord.class, text);
System.out.println(""+mr.getAddress() + " - "+mr.getName());
}
mr.setName("Rora");
manager.export(mr);
} catch (IOException | FixedFormatException ex) {
System.out.println(""+ex);
}
}
}
I have seen export method but don't understand how to use it? Nothing happens in above code
The export method returns a string representing the marshalled record.
In your code you would need to write out the result of the export command to a FileWriter. So:
before the while loop:
FileWriter fw = new FileWriter("d:/myrecords_modified.txt", true);
BufferedWriter bw = new BufferedWriter(fw);
after the while loop:
mr.setName("Rora");
String modifiedRecord = manager.export(mr);
bw.write(modifiedRecord);
I'm working on a homework assignment and have run into an odd "ArrayOutOfBoundsException" error - I know what the error means (essentially I'm trying to reference a location in an array that isn't there) but I'm not sure why it's throwing that error? I'm not sure what I'm missing, but obviously there must be some logic error somewhere that I'm not seeing.
PhoneDirectory.java
import java.util.HashMap;
import java.io.*;
class PhoneDirectory {
private HashMap<String, String> directoryMap;
File directory;
public PhoneDirectory() { //create file for phone-directory
directory = new File("phone-directory.txt");
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public PhoneDirectory(String phoneDirectoryFile) {
directory = new File(phoneDirectoryFile);
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public String Lookup(String personName) {
if(directoryMap.containsKey(personName))
return directoryMap.get(personName);
else
return "This person is not in the directory.";
}
public void AddOrChangeEntry(String name, String phoneNumber) {
//ASK IF "IF-ELSE" CHECK IS NECESSARY
if(directoryMap.containsKey(name))
directoryMap.put(name,phoneNumber); //if name is a key, update listing
else
directoryMap.put(name, phoneNumber); //otherwise - create new entry with name
}
public void DeleteEntry(String name) {
if(directoryMap.containsKey(name))
directoryMap.remove(name);
else
System.out.println("The person you are looking for is not in this directory.");
}
public void Write() {
try(BufferedWriter writeDestination = new BufferedWriter(new FileWriter(directory)))
{
for(String key : directoryMap.keySet())
{
writeDestination.write(key + ", " + directoryMap.get(key) + '\n');
writeDestination.newLine();
}
}
catch(IOException err) {
err.printStackTrace();
}
}
}
Driver.java
public class Driver {
PhoneDirectory list1;
public static void main(String[] args) {
PhoneDirectory list1 = new PhoneDirectory("test.txt");
list1.AddOrChangeEntry("Disney World","123-456-7890");
list1.Write();
}
}
Essentially I'm creating a file called "test.txt" and adding the line "Disney World, 123-456-7890" - what's weird is that the code still works - but it throws me that error anyway, so what's really happening? (For the record, I'm referring to the line(s): directoryMap.put(fileData[0], fileData[1]) - which would be line 14 and 28 respectively.)
I use the following code to write strings to my simple text file:
EDITED:
private String fileLocation="/mnt/sdcard/out.txt";
public void saveHisToFile()
{
if (prefs.getBoolean("saveHis", true) && mWordHis != null && mWordHis.size() >= 1)
{
StringBuilder sbHis = new StringBuilder();
Set<String> wordSet= new HashSet<String>(mWordHis);
for (String item : wordSet)
{
sbHis.append(item);
sbHis.append("\n");
}
String strHis = sbHis.substring(0, sbHis.length()-1);
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(new File(
fileLocation), true));
bw.write(strHis);
bw.newLine();
bw.close();
} catch (IOException e) {
}
}
}
The strings are successfully written to the text file, but weirdly, some strings are overwritten, such as:
apple
orange
grapes
grapes
grapes
apple
kiwi
My question is:
how can I stop a string being written more than once?
how can I stop writing a string (a line) to the file if it has already existed in the file?
I have consulted this post but failed to apply it to my case. Can you please give a little help? Thanks a lot in advance.
Try this:
public void saveHisToFile(Set<String> existingWords)
{
if (prefs.getBoolean("saveHis", true) && mWordHis != null && mWordHis.size() >= 1)
{
StringBuilder sbHis = new StringBuilder();
for (String item : mWordHis)
{
if (!existingWords.contains(item)) {
sbHis.append(item);
sbHis.append("\n");
}
}
String strHis = sbHis.substring(0, sbHis.length()-1);
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(new File(
fileLocation), true));
bw.write(strHis);
bw.newLine();
bw.close();
} catch (IOException e) {
}
}
}
I guess mWordHis is a List, which can contain duplicate entries.
You can first convert it to a Set (which doesn't allow duplicates) and print only the words in the Set.
Set<String> wordSet= new HashSet<>(mWordHis);
for (String item : wordSet)
{
sbHis.append(item);
sbHis.append("\n");
}
As #fge commented, LinkedHashSet may also be used if insertion order matters.
If you need to run the same code several times with the same file, you must either save in memory all the records you've already wrote to the file, or read the file and get all data before writing to it.
Edit:
I can only think about trimming the words as some may contain unneeded spaces:
Set<String> wordSet= new HashSet<>();
for (String item : mWordHis){
wordSet.add(item.trim());
}
This is a complete example on how to solve your problem:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashSet;
public class HisSaver {
private HashSet<String> uniqueTester = new HashSet<String>();
private String fileLocation="/mnt/sdcard/out.txt";
private static HisSaver instance = null;
private HisSaver() {
readWordsFromFile();
}
public static HisSaver getInstance() {
if(instance == null)
instance = new HisSaver();
return instance;
}
public void saveWord(String word) {
if(!uniqueTester.contains(word)) {
uniqueTester.add(word);
writeWordToFile(word);
}
}
private void writeWordToFile(String word) {
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(new File(
fileLocation), true));
bw.write(word);
bw.newLine();
bw.close();
} catch (IOException e) {
}
}
private void readWordsFromFile() {
try {
BufferedReader br = new BufferedReader(new FileReader(new File(
fileLocation)));
String line;
while((line = br.readLine()) != null) {
if(!uniqueTester.contains(line)) {
uniqueTester.add(line);
}
}
} catch (IOException e) {
}
}
}
Now to use this, you simply do the following in your code:
HisSaver hs = HisSaver.getInstance();
hs.saveWord("newWord");
This will insert the "newWord" if and only if it is not already in your file, provided that no other function in your code accesses this file. Please note: this solution is NOT thread safe!!!
Edit: Explanation of what the code does:
We create a class HisSaver which is a singleton. This is realized by making it's constructor private and providing a static method getInstance() which returns an initialized HisSaver. This HisSaver will already contain all preexisting words in your file and thus only append new words to it. Calling the getInstance() method from another class will give you a handle for this singleton and allow you to call saveWord without having to worry whether you have the right object in your hands, since only one instance of it can ever be instantiated.
You could add all the strings into a HashMap and check for each new String if it is are already in there.
Example:
HashMap<String,String> test = new HashMap<String,String>();
if(!test.containsKey(item)) {
test.put(item,"");
// your processing: example
System.out.println(item);
} else {
// Your processing of duplicates, example:
System.out.println("Found duplicate of: " + item);
}
Edit: or use a HashSet as shown by the other solutions ...
HashSet<String> test = new HashSet<String>();
if(!test.contains(item)) {
test.add(item);
// your processing: example
System.out.println(item);
} else {
// Your processing of duplicates, example:
System.out.println("Found duplicate of: " + item);
}
Edit2:
private String fileLocation="/mnt/sdcard/out.txt";
public void saveHisToFile()
{
if (prefs.getBoolean("saveHis", true) && mWordHis != null && mWordHis.size() >= 1)
{
StringBuilder sbHis = new StringBuilder();
HashSet<String> test = new HashSet<String>();
Set<String> wordSet= new HashSet<String>(mWordHis);
for (String item : wordSet)
{
if(!test.contains(item)) {
test.add(item);
// your processing: example
sbHis.append(item+System.lineSeparator());
} else {
// Your processing of duplicates, example:
//System.out.println("Found duplicate of: " + item);
}
}
String strHis = sbHis.toString();
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(new File(
fileLocation), true));
bw.write(strHis);
bw.newLine();
bw.close();
} catch (IOException e) {
}
}
}