Java 8 - How to read lines from file and store it to array conditionally

Question

im working on a java program that read a file with multiple lines , these lines has structure like this :

datadatadatadatadatadatadatadata         "X" DATAKEY      
datadatadatadatadatadatadatadata         F DATA
datadatadatadatadatadatadatadata         F DATA
datadatadatadatadatadatadatadata         F DATA
datadatadatadatadatadatadatadata         GDATA      
datadatadatadatadatadatadatadata         GDATA
datadatadatadatadatadatadatadata         GDATA       
datadatadatadatadatadatadatadata         G9    0000      
datadatadatadatadatadatadatadata         "Z" KEY2
datadatadatadatadatadatadatadata         "X" DATAKEY       
datadatadatadatadatadatadatadata         L 8888
datadatadatadatadatadatadatadata         L 5678444
datadatadatadatadatadatadatadata         L 7777
datadatadatadatadatadatadatadata         L114100000      
datadatadatadatadatadatadatadata         L11410444      
datadatadatadatadatadatadatadata         L9    0000      
datadatadatadatadatadatadatadata         "Z" KEY2
datadatadatadatadatadatadatadata         "X" DATAKEY     
datadatadatadatadatadatadatadata         L45543443
datadatadatadatadatadatadatadata         L45543443
datadatadatadatadatadatadatadata         L45543443
datadatadatadatadatadatadatadata         L45543443    
datadatadatadatadatadatadatadata         L45543443           
datadatadatadatadatadatadatadata         "Z" KEY2
.........

this is my working java code to read all lines from this file :

Path inputFile;

inputFile = Paths.get("inputDir", "myfileName");

fileLines = Files.readAllLines(inputFile, StandardCharsets.ISO_8859_1);

fileLines.forEach(System.out::println);

now my issue is , i want to read each block of line in a specific array dynamically (number of arrays equal number of block lines), a block of lines is constitued by line that contains "X" and ends with line contains "Z" , in my example i have tree blocks of lines , and i have to create 3 arrays each array should contains lines of each block.

can you please guide my on how i can achieve this using java 8 lambda methods.

Thanks in advance.

Answer 1

I resolve my Problem using the solution in this ticket : Java 8: How to convert List<String> to Map<String,List<String>>?

this is my final Code :

    Map<String, List<String>> map = fichierInialLines.stream()
            .collect(
                    Collectors.groupingBy(line -> line.substring(0,29), 
                            Collectors.mapping(line -> line, Collectors.toList()))
           );

Answer 2

Some old school java code:

List<String> fileLines = new ArrayList<>();
List<List<String>> records=new ArrayList<>();
List<String> tempRecord=null;
for(String fileLine:fileLines)
{
    if(fileLine.contains("\"X\""))
    {
        tempRecord=new ArrayList<>();
        tempRecord.add(fileLine); // add X line if necessary
    }
    else if (fileLine.contains("\"Y\""))
    {
        tempRecord.add(fileLine); // add Y line if necessary
        records.add(tempRecord);
        tempRecord=null;                
    } else {
        tempRecord.add(fileLine);
    }
}
// every entry in records contains a group of lines 

Oops: noticed you asked for a lambda way. sorry