protected void _handleFirstLine() throws IOException {
_handleFirstLine = false;
if (_schema.usesHeader()) {
int count = _schema.size();
if (count == 0) {
_reportMappingError(
"Schema specified that header line is to be written; but contains no column names");
}
for (CsvSchema.Column column : _schema) {
_writer.writeColumnName(column.getName());
}
_writer.endRow();
}
}
@Override
public final void writeStartArray() throws IOException {
_verifyValueWrite("start an array");
/* Ok to create root-level array to contain Objects/Arrays, but
* can not nest arrays in objects
*/
if (_writeContext.inObject()) {
if (!_skipValue) {
// First: column may have its own separator
int sep;
if (_nextColumnByName >= 0) {
CsvSchema.Column col = _schema.column(_nextColumnByName);
sep = col.isArray() ? col.getArrayElementSeparator() : -1;
} else {
sep = -1;
}
if (sep <= 0) {
if (!_schema.hasArrayElementSeparator()) {
_reportMappingError(
"CSV generator does not support Array values for properties without setting 'arrayElementSeparator' in schema");
}
sep = _schema.getArrayElementSeparator();
}
_arraySeparator = sep;
if (_arrayContents == null) {
_arrayContents = new StringBuilder();
} else {
_arrayContents.setLength(0);
}
_arrayElements = 0;
}
} else if (_arraySeparator >= 0) {
// also: no nested arrays, yet
_reportMappingError("CSV generator does not support nested Array values");
}
_writeContext = _writeContext.createChildArrayContext();
// and that's about it, really
}
private final void _writeFieldName(String name) throws IOException {
// just find the matching index -- must have schema for that
if (_schema == null) {
// not a low-level error, so:
_reportMappingError("Unrecognized column '" + name + "', can not resolve without CsvSchema");
}
// note: we are likely to get next column name, so pass it as hint
CsvSchema.Column col = _schema.column(name, _nextColumnByName + 1);
if (col == null) {
if (isEnabled(JsonGenerator.Feature.IGNORE_UNKNOWN)) {
_skipValue = true;
_nextColumnByName = -1;
return;
}
// not a low-level error, so:
_reportMappingError(
"Unrecognized column '" + name + "': known columns: " + _schema.getColumnDesc());
}
_skipValue = false;
// and all we do is just note index to use for following value write
_nextColumnByName = col.getIndex();
}
@Override
public void writeOmittedField(String fieldName) throws IOException {
// basically combination of "writeFieldName()" and "writeNull()"
if (_writeContext.writeFieldName(fieldName) == JsonWriteContext.STATUS_EXPECT_VALUE) {
_reportError("Can not skip a field, expecting a value");
}
// Hmmh. Should we require a match? Actually, let's use logic: if field found,
// assumption is we must add a placeholder; if not, we can merely ignore
CsvSchema.Column col = _schema.column(fieldName);
if (col == null) {
// assumed to have been removed from schema too
} else {
// and all we do is just note index to use for following value write
_nextColumnByName = col.getIndex();
// We can basically copy what 'writeNull()' does...
_verifyValueWrite("skip positional value due to filtering");
_writer.write(_columnIndex(), "");
}
}
@Override
public void writeNull() throws IOException {
_verifyValueWrite("write null value");
if (!_skipValue) {
if (_arraySeparator >= 0) {
_addToArray(_schema.getNullValueOrEmpty());
} else if (!_writeContext.inObject()) { // as per [#69]
// note: 'root' not enough, for case of wrap-as array, or serialize List
// or, to write 'empty Object' (for common case), would
// write single null, then finish row, like so:
/*
_writer.writeNull(_columnIndex());
finishRow();
*/
} else {
_writer.writeNull(_columnIndex());
}
}
}
static {
EMPTY_SCHEMA = CsvSchema.emptySchema();
}