org.marketcetera.modules.csv.CSVEmitter Maven / Gradle / Ivy
package org.marketcetera.modules.csv;
import org.marketcetera.util.misc.ClassVersion;
import org.marketcetera.util.misc.NamedThreadFactory;
import org.marketcetera.util.unicode.UnicodeInputStreamReader;
import org.marketcetera.util.unicode.DecodingStrategy;
import org.marketcetera.util.log.I18NBoundMessage1P;
import org.marketcetera.module.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.Map;
import java.util.HashMap;
import java.util.Hashtable;
import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import java.net.URL;
import java.net.MalformedURLException;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVStrategy;
/* $License$ */
/**
* A module that emits data contained in a CSV file as a series of maps,
* each instance containing a row of data. The first row of data is
* assumed to contain the column names. Each Map instance has the
* column name as the key and the value in the column as data.
* Each map instance has as many entries as the number of header columns.
* Rows that do not have any value for a column have an empty string
* value in the emitted map.
*
* All the keys and values in the map are of type string.
*
* The module accepts request parameters of following types:
*
* - {@link String} : interpreted as a URL, if that fails, a
* file path from which the csv file can be read. If the string starts
* with 'r:', it's stripped from the string and rows are emitted in
* the reverse order of their appearance.
* - {@link File}: path to the csv file.
* - {@link URL}: the url of the csv file.
*
*
* Module Features
*
* Capabilities Data Emitter DataFlow Request Parameters String, File or URL. Usage explained above. Stops data flows Yes, if there's no more data to emit or if there was an error reading data from the file/URL. Start Operation Initializes the thread pool for emitting data. Stop Operation Shuts down the thread pool. Management Interface none Factory {@link CSVEmitterFactory}
*
* @author [email protected]
*/
@ClassVersion("$Id: CSVEmitter.java 16841 2014-02-20 19:59:04Z colin $")
public class CSVEmitter extends Module implements DataEmitter {
/**
* Creates an instance.
*/
protected CSVEmitter() {
super(CSVEmitterFactory.INSTANCE_URN, true);
}
@Override
protected void preStart() {
mService = Executors.newCachedThreadPool(
new NamedThreadFactory("CSVEmitter-")); //$NON-NLS-1$
}
@Override
protected void preStop() {
mService.shutdownNow();
}
@Override
public void requestData(DataRequest inRequest,
DataEmitterSupport inSupport)
throws UnsupportedRequestParameterType,
IllegalRequestParameterValue {
Object obj = inRequest.getData();
if(obj == null) {
throw new IllegalRequestParameterValue(getURN(), null);
}
URL csv;
boolean isReverse = false;
try {
if(obj instanceof String) {
String s = (String)obj;
if(s.startsWith(PREFIX_REVERSE)) {
isReverse = true;
s = s.substring(PREFIX_REVERSE.length());
}
try {
csv = new URL(s);
} catch(MalformedURLException ignore) {
csv = new File(s).toURI().toURL();
}
} else if (obj instanceof File) {
csv = ((File)obj).toURI().toURL();
} else if (obj instanceof URL) {
csv = (URL) obj;
} else {
throw new UnsupportedRequestParameterType(getURN(), obj);
}
CSVReader reader = new CSVReader(csv, inSupport, isReverse);
Future future = mService.submit(reader);
mRequests.put(inSupport.getRequestID(), future);
} catch (MalformedURLException e) {
throw new IllegalRequestParameterValue(getURN(), obj, e);
}
}
@Override
public void cancel(DataFlowID inFlowID, RequestID inRequestID) {
Future future = mRequests.remove(inRequestID);
if (future != null) {
future.cancel(true);
}
}
/**
* This task reads the contents of a csv file and emits each row
* of the csv file as a Map instance.
*/
private static class CSVReader implements Callable {
/**
* Creates an instance.
*
* @param inSource The URL from which the csv file can be read.
* @param inSupport the handle to emit data.
* @param inReverse if the emitter should reverse the rows, emitting
* the last row first.
*/
private CSVReader(URL inSource, DataEmitterSupport inSupport,
boolean inReverse) {
mSource = inSource;
mSupport = inSupport;
mReverse = inReverse;
}
@Override
public Boolean call() throws Exception {
InputStream is = null;
try {
is = mSource.openStream();
String[][] rows = new CSVParser(new UnicodeInputStreamReader(is,
DecodingStrategy.SIG_REQ),
CSVStrategy.EXCEL_STRATEGY).getAllValues();
//Expect at least two rows, the first row is headers.
if(rows == null || rows.length < 2) {
mSupport.dataEmitError(new I18NBoundMessage1P(
Messages.INSUFFICIENT_DATA,
rows == null
? 0
: rows.length),
true);
return false;
}
if (mReverse) {
for(int i = rows.length - 1; i > 0; i--) {
mSupport.send(createMap(rows[0], rows[i]));
}
} else {
for(int i = 1; i < rows.length; i++) {
mSupport.send(createMap(rows[0], rows[i]));
}
}
//Terminate the data flow.
mSupport.dataEmitError(Messages.NO_MORE_DATA,true);
} catch (Throwable e) {
//Terminate the data flow if there's any error.
mSupport.dataEmitError(new I18NBoundMessage1P(
Messages.UNEXPECTED_ERROR, e.getLocalizedMessage()),
true);
} finally {
if (is != null) {
try {
is.close();
} catch (IOException ignore) {
}
}
}
return true;
}
/**
* Creates a map instance with the supplied key value arrays.
*
* @param inKeys The keys to be used in the map.
* @param inValues The values to be used in the map.
*
* @return A map instance containing key value pairs extracted
* from the supplied array. The map's size is the same size as
* the length of the supplied inKeys array.
*/
private Map createMap(String[] inKeys, String[] inValues) {
HashMap map = new HashMap();
for(int i = 0; i < inKeys.length; i++) {
map.put(inKeys[i], i < inValues.length? inValues[i]: ""); //$NON-NLS-1$
}
return map;
}
private final URL mSource;
private final boolean mReverse;
private final DataEmitterSupport mSupport;
}
private ExecutorService mService;
private final Map> mRequests =
new Hashtable>();
static final String PREFIX_REVERSE = "r:"; //$NON-NLS-1$
}
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