scriptella.driver.csv.CsvConnection Maven / Gradle / Ivy
/*
* Copyright 2006-2010 The Scriptella Project Team.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package scriptella.driver.csv;
import scriptella.core.EtlCancelledException;
import scriptella.driver.csv.opencsv.CSVReader;
import scriptella.driver.csv.opencsv.CSVWriter;
import scriptella.driver.text.AbstractTextConnection;
import scriptella.expression.PropertiesSubstitutor;
import scriptella.spi.ConnectionParameters;
import scriptella.spi.ParametersCallback;
import scriptella.spi.ProviderException;
import scriptella.spi.QueryCallback;
import scriptella.spi.Resource;
import scriptella.util.StringUtils;
import java.io.IOException;
import java.io.Writer;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Represents a connection to CSV file.
* For configuration details and examples see overview page.
*
* @author Fyodor Kupolov
* @version 1.0
*/
public class CsvConnection extends AbstractTextConnection {
protected static final Logger LOG = Logger.getLogger(CsvConnection.class.getName());
private CSVWriter out;
private Writer writer;
/**
* Name of the separator connection property.
* The delimiter to use for separating entries when reading from or writing to files.
*/
public static final String SEPARATOR = "separator";
/**
* Name of the quote connection property.
* The character to use for quoted elements when reading from or writing to files. Use empty string to suppress
* quoting.
*/
public static final String QUOTE = "quote";
/**
* Name of the headers connection property.
* true means the first line contains headers. Default value is true.
*
Only valid for <query> elements.
*/
public static final String HEADERS = "headers";
public CsvConnection(ConnectionParameters parameters) {
super(Driver.DIALECT, new CsvConnectionParameters(parameters));
}
public void executeScript(Resource scriptContent, ParametersCallback parametersCallback) throws ProviderException {
final CSVReader r;
try {
r = getScriptingElementReader(scriptContent);
} catch (IOException e) {
throw new CsvProviderException("Cannot open CSV script content.", e);
}
try {
executeScript(r, parametersCallback);
} catch (IOException e) {
throw new CsvProviderException("Cannot output CSV script.", e);
}
}
void executeScript(CSVReader reader, ParametersCallback parametersCallback) throws IOException {
CSVWriter out = getOut();
final CsvConnectionParameters csvParams = getConnectionParameters();
ParametersCallback formattingCallback = csvParams.getPropertyFormatter().format(parametersCallback);
final boolean trimLines = csvParams.isTrimLines();
PropertiesSubstitutor ps = new PropertiesSubstitutor(formattingCallback);
for (String[] row; (row = reader.readNext()) != null;) {
EtlCancelledException.checkEtlCancelled();
for (int i = 0; i < row.length; i++) {
String field = row[i];
if (field != null) {
if (trimLines) {//removing extra whitespaces by default
field = field.trim();
}
row[i] = ps.substitute(field);
}
}
//If only one column and empty - skip this row
if (row.length == 1 && StringUtils.isAsciiWhitespacesOnly(row[0])) {
continue;
}
if (isReadonly()) {
if (LOG.isLoggable(Level.INFO)) {
LOG.info("Readonly Mode - " + Arrays.deepToString(row) + " has been skipped.");
}
} else {
try {
out.writeNext(row);
counter.statements++;
} catch (Exception e) {
throw new CsvProviderException("Failed to write CSV row ", e);
}
}
}
if (csvParams.isFlush()) {
writer.flush();
}
}
public void executeQuery(Resource queryContent, ParametersCallback parametersCallback, QueryCallback queryCallback) throws ProviderException {
if (out != null) {
throw new CsvProviderException("Cannot query and update a CSV file simultaneously.");
}
final CSVReader queryContentReader;
try {
queryContentReader = getScriptingElementReader(queryContent);
} catch (IOException e) {
throw new CsvProviderException("Failed to read query content", e);
}
final CsvConnectionParameters csvParams = getConnectionParameters();
try {
final CsvQuery q = newCsvQuery(queryContentReader, new PropertiesSubstitutor(parametersCallback));
CSVReader inputCSVContentReader = new CSVReader(newInputReader(), csvParams.getSeparator(), csvParams.getQuote(), csvParams.getSkipLines());
q.execute(inputCSVContentReader, queryCallback, counter);
} catch (IOException e) {
throw new CsvProviderException("Failed to open CSV file " + csvParams.getUrl() + " for input", e);
}
}
private CSVReader getScriptingElementReader(Resource content) throws IOException {
return new CSVReader(content.open());
}
/**
* @return lazily intialized writer.
*/
protected CSVWriter getOut() {
if (out == null) {
final CsvConnectionParameters csvParams = getConnectionParameters();
try {
writer = newOutputWriter();
out = new CSVWriter(writer, csvParams.getSeparator(), csvParams.getQuote(), csvParams.getEol());
} catch (IOException e) {
throw new CsvProviderException("Unable to open URL " + csvParams.getUrl() + " for output", e);
}
}
return out;
}
/**
* Template factory method to instantiate query handlers.
*
* @param csvReader CSV reader to use for parsing.
* @param ps properties substitutor.
* @return constructed query for a specified input and parameters.
*/
protected CsvQuery newCsvQuery(CSVReader csvReader, PropertiesSubstitutor ps) {
return new CsvQuery(csvReader, ps, getConnectionParameters());
}
public void close() throws ProviderException {
if (out != null) {
try {
out.close();
writer = null;
} catch (Exception e) {
LOG.log(Level.INFO, "A problem occured while trying to close CSV writer", e);
}
}
}
@Override
protected CsvConnectionParameters getConnectionParameters() {
return (CsvConnectionParameters) super.getConnectionParameters();
}
}