universal-reader

Description

The library intended to read or process content from files with different formats (like csv, txt, xls, xlsx) via one general interface.

Install

Gradle

compile('com.github.boggard:universal-reader:2.0.1')

Maven

<dependency>
    <groupId>com.github.boggard</groupId>
    <artifactId>universal-reader</artifactId>
    <version>2.0.0</version>
</dependency>

Getting started

Entry point

To process file with data you need to call static method

UniversalReader.processRecords(FileSource fileSource, ContentHandler<R> contentsHandler, ReaderConfiguration configuration)

About each parameter below.

FileSource

Interface for wrapping the to be processed.

Example for java.io.File:

public class SystemFileSource implements FileSource {
    
    private final File file;

    public SystemFileSource(File file) {
        this.file = file;
    }

    @Override
    public String getFileName() {
        return file.getName();
    }

    @Override
    public InputStream getInputStream() throws IOException {
        return new FileInputStream(file);
    }
}

ContentHandler

To handle content of file you need to implements interface ContentHandler which contains events of reading process. Simple example of implementation to read list of records from file:

ContentHandler<Integer> contentHandler = new ContentHandler<Integer>() {
                private int recordsCount = 0;
                private String[] currentRecord;

                @Override
                public void startRecord() {
                    currentRecord = new String[2];
                }

                @Override
                public void startField(int index, String field) {
                    switch(index) {
                        case 0: //first field of record
                            currentRecord[0] = field;
                            break;
                        case 1: //second field of record
                            currentRecord[1] = field;
                            break;
                    }
                }

                @Override
                public void endRecord() {
                    //do something with record, save for example
                    save(currentRecord);
                    recordsCount++;
                }

                @Override
                public Integer getResult() {
                    return recordsCount;
                }
            };

As you see the interface is a generic and you can specify the result type you want.

ReaderConfiguration

Class for content reading utility configurations like records or fields separator symbol.

You can use factory constructors

• to create default configuration:

ReaderConfiguration.defaultReaderConfiguration();

• to create default configuration for files with header (start line index = 1 instead of 0):

ReaderConfiguration.withHeaderDefaultConfiguration();

• to create custom configuration:

ReaderConfiguration.customConfiguration("\n", "\t", 2);