done

src/main/java/rocks/zipcode/AlphaCharDocument.java

@@ -1,6 +1,10 @@
 package rocks.zipcode;
 
+import java.io.BufferedWriter;
+import java.io.FileWriter;
 import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * @author leon on 16/11/2018.
@@ -12,9 +16,22 @@ public class AlphaCharDocument extends Document {
 
     @Override
     public void write(String contentToBeWritten) {
+       if(isAlpha(contentToBeWritten)){
+           super.write(contentToBeWritten);
+       }
+       else
+           throw new IllegalArgumentException();
     }
 
     private Boolean isAlpha(String s) {
-        return null;
+      /*  boolean check = false;
+        for(int i = 0; i<s.length();i++){
+            if(Character.isLetter(s.charAt(i)))
+                check = true;
+        }
+        return check;*/
+        Pattern pattern = Pattern.compile("[a-z]", Pattern.CASE_INSENSITIVE);
+        Matcher matcher = pattern.matcher(s);
+        return matcher.find();
     }
 }

src/main/java/rocks/zipcode/Document.java

@@ -1,7 +1,14 @@
 package rocks.zipcode;
 
+import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;
+
 import java.io.*;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -24,41 +31,101 @@ public class Document implements DocumentInterface {
 
     @Override
     public void write(String contentToBeWritten) {
+        try {
+            fileWriter.write(contentToBeWritten);
+            fileWriter.flush();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
     }
 
     @Override
     public void write(Integer lineNumber, String valueToBeWritten) {
+        try {
+            List<String> lines = Files.readAllLines(file.toPath());
+            lines.set(lineNumber, valueToBeWritten);
+            Files.write(file.toPath(), lines);
+        }catch (IOException io){
+            io.printStackTrace();
+        }
     }
 
     @Override
     public String read(Integer lineNumber) {
-        return null;
+        String line = null;
+        try {
+            line= Files.readAllLines(Paths.get(String.valueOf(file))).get(lineNumber);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return line;
     }
 
     @Override
     public String read() {
-        return null;
+        StringBuilder stringBuilder = new StringBuilder();
+        try {
+            FileReader fileReader = new FileReader(file);
+            BufferedReader bufferedReader = new BufferedReader(fileReader);
+            String line = "";
+            while ((line = bufferedReader.readLine()) != null)
+                stringBuilder.append(line + "\n");
+            stringBuilder.deleteCharAt(stringBuilder.length() - 1);
+        }catch (IOException exception){
+            exception.printStackTrace();
+        }
+        return stringBuilder.toString();
     }
 
     @Override
     public void replaceAll(String stringToReplace, String replacementString) {
+        try {
+            Path path = Paths.get(String.valueOf(file));
+            Charset charset = StandardCharsets.UTF_8;
+
+            String content = new String(Files.readAllBytes(path), charset);
+            content = content.replaceAll(stringToReplace, replacementString);
+            Files.write(path, content.getBytes(charset));
+        }catch (IOException io){
+            io.printStackTrace();
+        }
     }
 
     @Override
     public void overWrite(String content) {
+        try {
+            Writer fileWriter = new FileWriter(file, false);
+            fileWriter.write(content);
+            fileWriter.flush();
+            fileWriter.close();
+        }
+        catch (IOException io){
+            io.printStackTrace();
+        }
     }
 
     public List<String> toList() {
-        return null;
+        List<String> list = new ArrayList<>();
+        try {
+            FileReader fileReader = new FileReader(file);
+            BufferedReader bufferedReader = new BufferedReader(fileReader);
+            String line = "";
+            while ((line = bufferedReader.readLine()) != null)
+                list.add(line);
+        }catch (IOException io){
+            io.printStackTrace();
+        }
+        return list;
     }
 
     @Override
     public File getFile() {
-        return null;
+        return this.file;
     }
 
     @Override
     public String toString() {
-        return null;
+        String content = read();
+        return file.toString() + "{" + content + "}";
     }
 }

src/main/java/rocks/zipcode/NumericCharDocument.java

@@ -1,6 +1,8 @@
 package rocks.zipcode;
 
 import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * @author leon on 16/11/2018.
@@ -12,9 +14,15 @@ public class NumericCharDocument extends Document {
 
     @Override
     public void write(String contentToBeWritten) {
+        if(isNumeric(contentToBeWritten))
+            super.write(contentToBeWritten);
+        else
+            throw new IllegalArgumentException();
     }
 
     private Boolean isNumeric(String s) {
-        return null;
+        Pattern pattern = Pattern.compile("[0-9]");
+        Matcher matcher = pattern.matcher(s);
+        return matcher.find();
     }
 }

src/main/java/rocks/zipcode/SpecialCharDocument.java

@@ -1,6 +1,8 @@
 package rocks.zipcode;
 
 import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * @author leon on 18/11/2018.
@@ -12,9 +14,15 @@ public class SpecialCharDocument extends Document {
 
     @Override
     public void write(String contentToBeWritten) {
+        if(isSpecialCharacters(contentToBeWritten))
+            super.write(contentToBeWritten);
+        else
+            throw new IllegalArgumentException();
     }
 
     private Boolean isSpecialCharacters(String s) {
-        return null;
+        Pattern pattern = Pattern.compile("[^0-9a-z]", Pattern.CASE_INSENSITIVE);
+        Matcher matcher = pattern.matcher(s);
+        return matcher.find();
     }
 }