Package org.jmonks.batch.io.flat

Flat file implementation for the IO API.

See:
Description

Class Summary

DelimitedFlatFileFieldSpec	DelimitedFlatFileFieldSpec represents field-spec element in the record spec element belongs to the delimited flat file type.
DelimitedFlatFileFileSpec	DelimitedFlatFileFileSpec represents the file spec defines the flat file where all the fields in the records delimited with a particular character or value.
DelimitedFlatFileReader	DelimitedFlatFileReader reads the specified delimited flat file according to the given file spec and returns the recrods on the needed basis.
DelimitedFlatFileRecordSpec	DelimitedFlatFileRecordSpec represents record-spec element in the file spec belongs to the delimited flat file type.
DelimitedFlatFileWriter	DelimitedFlatFileWriter writes the file according to the given file spec with the data submitted in the form of WriterRecord's.
FixedWidthFlatFileFieldSpec	FixedWidthFlatFileFieldSpec represents field-spec element in the record spec belongs to the fixed width flat file type.
FixedWidthFlatFileFileSpec	FixedWidthFlatFileFileSpec represents the file spec defines the flat file where each different kind of record starts with a particular value and the fields in each record will have start and end position.
FixedWidthFlatFileReader	FixedWidthFlatFileReader reads the specified fixed width flat file according to the given file spec and returns the recrods on the needed basis.
FixedWidthFlatFileRecordSpec	FixedWidthFlatFileRecordSpec represents record-spec element in the file spec belongs to the fixed width flat file type.
FixedWidthFlatFileWriter	FixedWidthFlatFileWriter writes the file according to the given file spec with the data submitted in the form of WriterRecord's.
FlatFileReader	FlatFileReader reads the specified fixed width flat file according to the given file spec and returns the recrods on the needed basis.
FlatFileWriter	FlatFileWriter writes/generates the file according to the given file spec with the data submitted in the form of WriterRecord's.

Package org.jmonks.batch.io.flat Description

Flat file implementation for the IO API.

Flat files are the common type of files being used by the enterprises to exchange the data. This package provides the implementation to read and write two flat file formats fixed width and delimited flat files. Implementation assumes that each line in a flat file corresponds to a record and there is a way to identify each record and each field in that record.

Fixed Width Flat File Implementation

Fixed Width flat files consists of set of different records where each record is starts with some value to identify the record and each record consists of set of of fields where each field starts at one position and ends at one position.

Defining the file spec for fixed width flat files

File spec which descibes the fixed width flat file expects the file-type attribute value should be "fixed-width-flat". It doesnt require any additional attributes along with the file-type attribute.

             <file-spec file-type="fixed-width-flat">
             </file-spec>
    

There could be multiple record specs exists in a file spec. Along with the record-type attribute, it requires two additional attributes starts-with which tells the value that the record should starts with and record-length which tells the lenght of the record.

             <file-spec file-type="fixed-width-flat">
                    <record-spec record-type="DETAIL" starts-with="5" record-length="42">
                    </record-spec>
             </file-spec>
    

There could be multiple field specs exists in a single record spec. Field spec requires few additional attributes along with the field-name attribute to identify or extract the field from the record. These attributes are start-pos which tells the starting position of the field in the record and end-pos which tells the ending position of the field in the record. Starting index in a record starts with "1".

             <file-spec file-type="fixed-width-flat">
                    <record-spec record-type="DETAIL" starts-with="5" record-length="42">
                            <field-spec field-name="field-name1" start-pos="12" end-pos="23"/> 
                    </record-spec>
             </file-spec>
    

Reading the records from fixed width flat files

Reading the records from the fixed width flat files is fairly simple.

    
        InputStream fileSpecInputStream= // Get the input stream for the XML file contains the file structure.
        InputStream fileInputStream= // Get the input stream of the file to be read.
        FileReader reader=FileReader.getFileReader(fileInputStream,fileSpecInputStream);
        ReaderRecord record=null;
        while((record=reader.getNextRecord())!=null)
        {
            if(record.getRecordType().equals(RecordType.DETAIL))
            {
                String fieldValue1=record.readField("field-name1");
                // Read the rest of the field and does the processing.
            }
        }
        reader.close();
    
    

Writing the records into fixed width flat files

Writing the records into fixed width flat files is fairly simple.

    
        InputStream fileSpecInputStream= // Get the input stream for the XML file contains the file structure.
        OutputStream fileOutputStream= // Get the output stream of the file to be written/generated.
        FileWriter writer=FileWriter.getFileWriter(fileOutputStream,fileSpecInputStream);
        WriterRecord record=writer.createWriterRecord(RecordType.DETAIL);
        record.writeField("field-name1","field-value1");
        // Write all the other field values into the writer record.
        writer.writeRecord(record);
        writer.close();
    
    

Delimited Flat File Implementation

Delimited flat files consists of set of records of same type where all the records consists of same number of fields and each field is are delimited by a special value in the record.

Defining the file spec for delimited flat files

File spec which descibes the delimited flat file expects the file-type attribute value should be "delimited-flat". It doesnt require any additional attributes along with the file-type attribute.

             <file-spec file-type="delimited-flat">
             </file-spec>
    

Since all the records in delimited flat file of the same type, it allows only one record spec should exists in the file spec. Along with the record-type attribute, it requires two additional attributes delimiter and field-count. Attributes delimiter tells the value that delimites fields among the record and attribute field-count tells the number of fields can exists in the record.

             <file-spec file-type="delimited-flat">
                    <record-spec record-type="DETAIL" delimiter="|" field-count="4">
                    </record-spec>
             </file-spec>
    

There could be multiple field specs exists in a record spec. Field spec requires one additional attributes along with the field-name attribute to identify or extract the field from the record. This attribute is index which tells the position of the field in the record. Starting index in a record starts with "1".

             <file-spec file-type="delimited-flat">
                    <record-spec record-type="DETAIL" delimiter="|" field-count="4">
                            <field-spec field-name="field-name1" index="3"/> 
                    </record-spec>
             </file-spec>
    

Reading the records from delimited flat files

Reading the records from the delimited flat files is fairly simple.

    
        InputStream fileSpecInputStream= // Get the input stream for the XML file contains the file structure.
        InputStream fileInputStream= // Get the input stream of the file to be read.
        FileReader reader=FileReader.getFileReader(fileInputStream,fileSpecInputStream);
        ReaderRecord record=null;
        while((record=reader.getNextRecord())!=null)
        {
            if(record.getRecordType().equals(RecordType.DETAIL))
            {
                String fieldValue1=record.readField("field-name1");
                // Read the rest of the field and does the processing.
            }
        }
        reader.close();
    
    

Writing the records into delimited flat files

Writing the records into delimited flat files is fairly simple.

    
        InputStream fileSpecInputStream= // Get the input stream for the XML file contains the file structure.
        OutputStream fileOutputStream= // Get the output stream of the file to be written/generated.
        FileWriter writer=FileWriter.getFileWriter(fileOutputStream,fileSpecInputStream);
        WriterRecord record=writer.createWriterRecord(RecordType.DETAIL);
        record.writeField("field-name1","field-value1");
        // Write all the other field values into the writer record.
        writer.writeRecord(record);
        writer.close();