blackmo18 / kotlin-grass

Kotlin Csv to Data Class Parser

Csv File to Kotlin Data Class Parser
Currently, it requires to have @ExperimentalStdlibApi on the class/method using this Library.
Requires kotlin-csv by doyaaaaaken for reading csv file.

Features

1. Simple And Direct

• No hard configuration
• No invasive annotations to data class
• Custom mapping
• Nullable Data Types

2. Primitive Types

• Short
• Int
• Long
• Float
• Double
• Boolean
• String

3. Support for Java 8 Date Time Apis

• LocalTime
• LocalDateTime
• LocalDate
• Custom Formatting

Usage

Gradle DSL:

//doyaaaaaken's kotlin-csv
implementation("com.github.doyaaaaaken:kotlin-csv-jvm:0.15.2")
//kotlin-grass
implementation("io.github.blackmo18:kotlin-grass-core-jvm:1.0.0")
implementation("io.github.blackmo18:kotlin-grass-parser-jvm:0.8.0")

Maven:

<dependency>
    <groupId>com.github.doyaaaaaken</groupId>
    <artifactId>kotlin-csv-jvm</artifactId>
    <version>0.15.2</version>
</dependency>
<dependency>
    <groupId>io.github.blackmo18</groupId>
    <artifactId>kotlin-grass-core-jvm</artifactId>
    <version>1.0.0</version>
</dependency>
<dependency>
    <groupId>io.github.blackmo18</groupId>
    <artifactId>kotlin-grass-parser-jvm</artifactId>
    <version>0.8.0</version>
</dependency>

Examples

CSV file

short	int	long	float	double	boolean	string
0	1	2	3.0	4.0	true	hello

Declaring data class

    data class PrimitiveTypes(
        val short: Short,
        val int: Int,
        val long: Long,
        val float: Float,
        val double: Double,
        val boolean: Boolean,
        val string: String
    )

Nullable Data Types

If a variable in your data class is a nullable, all you have to do is mark it with ?

    data class NullableData(
        val nullableString: String?,
        val nullableInt: Int? = null,
        ...
    )

Parsing to data class

    val csvContents = csvReader().readAllWithHeader(file)
    val dataClasses = grass<PrimitiveTypes>().harvest(csvContents)

Parsing to data class using Kotlin Flow

    val contents = File("file/path").inputStream()
    val dataClasses: Flow<PrimitiveTypes> = csvReader().openAsync(contents) {
        val data = readAllWithHeaderAsSequence().asFlow()
        grass<PrimitiveTypes>().harvest(data)
    }

Custom Configuration

Option	default value	description
dateFormat	yyyy-MM-dd	date format
timeFormat	HH:mm	time format
dateTimeSeparator	(space)	date time separator
trimWhiteSpace	true	trims white spaces on csv entries
ignoreUnknownFields	false	ignore unknown / unmapped fields in input
caseSensitive	true	case sensitive header matching
customKeyMap	null	Map<String,String> custom key mapping, priority if not empty or null
customKeyMapDataProperty	null	Map<String, KProperty<*>> custom key mapping

Java Date Time API Support

csv file

time	datetime	date
12:00	2020-12-31 12:00	2020-12-31

Date and Time Types

Import the following extension library

implementation("io.github.blackmo18:kotlin-grass-date-time-jvm:0.8.0")

    data class DateTimeTypes(
        val time: LocalTime,
        val datetime: LocalDateTime,
        val date: LocalDate,
    )

Customize Formatting

    val grass = grass<DateTimeTypes> {
        dateFormat = "MM-dd-yyyy"
        timeFormat = "HH:mm:ss"
        dateTimeSeparator = "/"
        customDataTypes = arrayListOf(Java8DateTime)
    }

Custom Mapping Support

CSV file

hour	birthdate
12:00	2020-12-31

Code

    data class DateTime(
        val time: LocalTime,
        val date: LocalDate,
    )

    val grass = grass<DateTimeTypes> {
        customKeyMap = mapOf("hour" to "time", "birthdate" to "date")
    }

    // or

    val grass = grass<DateTimeTypes> {
        customKeyMapDataProperty = mapOf("hour" to DateTime::time, "birthdate" to DateTime::date)
    }

🤝 Contributing

Contributions, issues and feature requests are welcome!
Feel free to check issues page.

Changelog

Show your support

Give a ⭐️ if this project helped you!

📝 License

Copyright © 2020 blackmo18.
This project is Apache License 2.0 licensed.

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This project inspired ❤️ by kotlin-csv