net.sf.flatpack.writer.FixedLengthWriter Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of flatpack

Simple Java delimited and fixed width file parser. Handles CSV, Excel CSV, Tab, Pipe delimiters, just to name a few. Maps column positions in the file to user friendly names via XML. See FlatPack Feature List under News for complete feature list.

There is a newer version: 4.0.4

Show newest version

package net.sf.flatpack.writer;

import java.io.IOException;
import java.math.BigDecimal;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import net.sf.flatpack.structure.ColumnMetaData;
import net.sf.flatpack.util.FPConstants;

/**
 *
 * @author Dirk Holmes and Holger Holger Hoffstatte
 */
public class FixedLengthWriter extends AbstractWriter {
    private static final int MAX_CHAR_TO_USE_LOOP = 8;
    private final Map columnMapping;
    private final char padChar;

    protected FixedLengthWriter(final Map parsedMapping, final java.io.Writer output, final char padChar) throws IOException {
        super(output);
        this.columnMapping = parsedMapping;
        this.padChar = padChar;
    }

    @Override
    public Writer addRecordEntry(final String columnName, final Object value) {
        if (value != null) {
            final ColumnMetaData metaData = this.getColumnMetaData(columnName);

            final String valueString = value.toString();
            if (valueString.length() > metaData.getColLength()) {
                throw new IllegalArgumentException(valueString + " exceeds the maximum length for column " + columnName + "("
                        + metaData.getColLength() + ")");
            }
        }
        return super.addRecordEntry(columnName, value);
    }

    @Override
    public Writer nextRecord() throws IOException {
        for (final ColumnMetaData element : getColumnMetaData()) {
            final Object value = this.getRowMap().get(element.getColName());
            this.write(this.formattedValue(value, element));
        }

        return super.nextRecord();
    }

    protected char[] formattedValue(final Object val, final ColumnMetaData element) {
        Object value = val;
        if (value == null) {
            // TODO DO: maybe have a way to substitute default values here?
            value = "";
        }

        String stringValue;
        if (value instanceof BigDecimal) {
            final BigDecimal bd = (BigDecimal) value;
            stringValue = bd.signum() == 0 ? "0" : bd.toPlainString();
        } else {
            stringValue = value.toString();
        }

        final int stringLength = stringValue.length();

        final int columnLength = element.getColLength();
        final char[] formattedValue = new char[columnLength];

        /*
         * Copy the contents of the original string; for Strings up to ~8-10
         * characters this loop is consistently faster than String.getChars().
         * Short Strings are usually the majority of values in fixed-width data
         * columns.
         */
        final int numCharacters = Math.min(stringLength, columnLength);
        if (numCharacters < MAX_CHAR_TO_USE_LOOP) {
            for (int i = 0; i < numCharacters; i++) {
                formattedValue[i] = stringValue.charAt(i);
            }
        } else {
            stringValue.getChars(0, numCharacters, formattedValue, 0);
        }

        if (stringLength < columnLength) {
            // pad if necessary
            Arrays.fill(formattedValue, stringLength, columnLength, padChar);
        }

        return formattedValue;
    }

    @Override
    protected boolean validateColumnTitle(final String columnTitle) {
        final Map columnNameToIndex = (Map) columnMapping.get(FPConstants.COL_IDX);
        return columnNameToIndex.keySet().contains(columnTitle);
    }

    @Override
    public Writer printFooter() {
        return this;
    }

    @Override
    public Writer printHeader() {
        return this;
    }

    /**
     * @return List of ColumnMetaData objects describing the mapping defined in
     *         the XML file.
     */
    private List getColumnMetaData() {
        return (List) columnMapping.get(FPConstants.DETAIL_ID);
    }

    private ColumnMetaData getColumnMetaData(final String columnName) {
        for (final ColumnMetaData element : getColumnMetaData()) {
            if (element.getColName().equals(columnName)) {
                return element;
            }
        }

        throw new IllegalArgumentException("Column \"" + columnName + "\" unknown");
    }
}