/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* This program is free software: you can redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License along with this program.
* If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.io;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Pattern;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.example.utils.ExampleSetBuilder;
import com.rapidminer.example.utils.ExampleSets;
import com.rapidminer.operator.OperatorCreationException;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.preprocessing.GuessValueTypes;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeBoolean;
import com.rapidminer.parameter.ParameterTypeString;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorService;
import com.rapidminer.tools.Tools;
import com.rapidminer.tools.io.Encoding;
/**
* <p>
* This operator reads an example set from an URL. The format has to be a CSV format with ';' as
* column separator and nominal values have to be quoted with a double quote ("). A quote
* inside of a nominal value has to be escaped by a backslash like in \". The first row is
* allowed to contain the column names which has to be indicated by the corresponding parameter.
* Comments are not allowed, unknown attribute values can be marked with empty strings or a question
* mark.
* </p>
*
* <p>
* This operator is not nearly as powerful as the operators ExampleSource or SimpleExampleSource but
* is on the other hand able to read data from arbitrary places as long as the format fits the
* specification above. Please note also that the usage of this operator hardly allows for a correct
* meta data description which might lead to problems if the meta data between training and test set
* differ in a learning scenario.
* </p>
*
* <p>
* Attribute roles can not be directly set during loading but the operator ChangeAttributeRole has
* to be used after loading in order to change the roles.
* </p>
*
* @rapidminer.index url
* @author Ingo Mierswa
*/
public class URLExampleSource extends AbstractExampleSource {
public static final String PARAMETER_URL = "url";
public static final String PARAMETER_COLUMN_SEPARATORS = "column_separators";
/** The parameter name for "Character that is used as decimal point." */
public static final String PARAMETER_DECIMAL_POINT_CHARACTER = "decimal_point_character";
public static final String PARAMETER_READ_ATTRIBUTE_NAMES = "read_attribute_names";
public static final String PARAMETER_SKIP_ERROR_LINES = "skip_error_lines";
public URLExampleSource(final OperatorDescription description) {
super(description);
}
@Override
public ExampleSet createExampleSet() throws OperatorException {
boolean readAttributeNames = getParameterAsBoolean(PARAMETER_READ_ATTRIBUTE_NAMES);
boolean skipErrorLines = getParameterAsBoolean(PARAMETER_SKIP_ERROR_LINES);
char decimalPointCharacter = getParameterAsString(PARAMETER_DECIMAL_POINT_CHARACTER).charAt(0);
ExampleSetBuilder builder = null;
BufferedReader in = null;
try {
InputStream inputStream = getParameterAsInputStream(PARAMETER_URL);
in = new BufferedReader(new InputStreamReader(inputStream, Encoding.getEncoding(this)));
String line = null;
Pattern separatorPattern = Pattern.compile(getParameterAsString(PARAMETER_COLUMN_SEPARATORS));
int rowLength = -1;
int lineCounter = 1;
List<Attribute> attributes = new ArrayList<>();
while ((line = in.readLine()) != null) {
// skip empty lines
if (line.trim().length() == 0) {
continue;
}
// split row
String[] row = Tools.quotedSplit(line, separatorPattern);
// check for row length
if (rowLength >= 0 && rowLength != row.length) {
if (skipErrorLines) {
logWarning("Wrong number of columns in line " + lineCounter + ": was " + row.length + ", expected "
+ rowLength);
continue;
} else {
throw new UserError(this, 302, getParameter(PARAMETER_URL), "Wrong number of columns in line "
+ lineCounter + ": was " + row.length + ", expected " + rowLength);
}
}
// store row length for first row
if (rowLength < 0) {
rowLength = row.length;
}
// create table for first line
boolean skipLine = false;
if (builder == null) {
int attCounter = 1;
for (String r : row) {
if (readAttributeNames) {
attributes.add(AttributeFactory.createAttribute(r, Ontology.NOMINAL));
} else {
attributes.add(AttributeFactory.createAttribute("Att" + attCounter, Ontology.NOMINAL));
}
attCounter++;
}
builder = ExampleSets.from(attributes);
if (readAttributeNames) {
skipLine = true;
}
}
// store row as data row
if (!skipLine) {
double[] data = new double[row.length];
for (int i = 0; i < data.length; i++) {
data[i] = attributes.get(i).getMapping().mapString(row[i]);
}
builder.addRow(data);
}
lineCounter++;
}
} catch (IOException e) {
throw new UserError(this, 302, getParameter(PARAMETER_URL), e.getMessage());
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
// do nothing
}
}
}
ExampleSet exampleSet = builder.build();
try {
GuessValueTypes guessValuesTypes = OperatorService.createOperator(GuessValueTypes.class);
guessValuesTypes.setParameter(GuessValueTypes.PARAMETER_DECIMAL_POINT_CHARACTER,
Character.toString(decimalPointCharacter));
exampleSet = guessValuesTypes.apply(exampleSet);
} catch (OperatorCreationException e) {
throw new OperatorException("Cannot create GuessValueTypes: " + e, e);
}
return exampleSet;
}
@Override
protected boolean supportsEncoding() {
return true;
}
@Override
public List<ParameterType> getParameterTypes() {
List<ParameterType> types = new LinkedList<>();
types.add(new ParameterTypeString(PARAMETER_URL, "The url to read the data from.", false));
ParameterType type = new ParameterTypeString(PARAMETER_COLUMN_SEPARATORS,
"Column separators for data files (regular expression)", ",\\s*|;\\s*|\\s+");
type.setExpert(false);
types.add(type);
type = new ParameterTypeBoolean(PARAMETER_READ_ATTRIBUTE_NAMES,
"Read attribute names from file (assumes the attribute names are in the first line of the file).", false);
type.setExpert(false);
types.add(type);
types.add(new ParameterTypeBoolean(PARAMETER_SKIP_ERROR_LINES,
"Indicates if lines which can not be read should be skipped instead of letting this operator fail its execution.",
false));
types.add(
new ParameterTypeString(PARAMETER_DECIMAL_POINT_CHARACTER, "Character that is used as decimal point.", "."));
types.addAll(super.getParameterTypes());
return types;
}
}