RegexAnalysis.java

/*
 * Copyright (c) 2013 Data Harmonisation Panel
 * 
 * All rights reserved. This program and the accompanying materials are made
 * available under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     HUMBOLDT EU Integrated Project #030962
 *     Data Harmonisation Panel <http://www.dhpanel.eu>
 */

package eu.esdihumboldt.cst.functions.string;

import java.text.MessageFormat;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.collect.ListMultimap;

import eu.esdihumboldt.hale.common.align.model.impl.PropertyEntityDefinition;
import eu.esdihumboldt.hale.common.align.transformation.engine.TransformationEngine;
import eu.esdihumboldt.hale.common.align.transformation.function.PropertyValue;
import eu.esdihumboldt.hale.common.align.transformation.function.TransformationException;
import eu.esdihumboldt.hale.common.align.transformation.function.impl.AbstractSingleTargetPropertyTransformation;
import eu.esdihumboldt.hale.common.align.transformation.function.impl.NoResultException;
import eu.esdihumboldt.hale.common.align.transformation.report.TransformationLog;

/**
 * Regex string analysis function.
 * 
 * @author Andrea Antonello (www.hydrologis.com)
 */
public class RegexAnalysis extends AbstractSingleTargetPropertyTransformation<TransformationEngine>
		implements RegexAnalysisFunction {

	@Override
	protected Object evaluate(String transformationIdentifier, TransformationEngine engine,
			ListMultimap<String, PropertyValue> variables, String resultName,
			PropertyEntityDefinition resultProperty, Map<String, String> executionParameters,
			TransformationLog log) throws TransformationException, NoResultException {
		if (getParameters() == null || getParameters().get(PARAMETER_REGEX_PATTERN) == null
				|| getParameters().get(PARAMETER_REGEX_PATTERN).isEmpty()) {
			throw new TransformationException(MessageFormat
					.format("Mandatory parameter {0} not defined", PARAMETER_REGEX_PATTERN));
		}
		if (getParameters() == null || getParameters().get(PARAMETER_OUTPUT_FORMAT) == null
				|| getParameters().get(PARAMETER_OUTPUT_FORMAT).isEmpty()) {
			throw new TransformationException(MessageFormat
					.format("Mandatory parameter {0} not defined", PARAMETER_OUTPUT_FORMAT));
		}

		String regexPattern = getParameters().get(PARAMETER_REGEX_PATTERN).get(0).as(String.class);
		String outputFormat = getParameters().get(PARAMETER_OUTPUT_FORMAT).get(0).as(String.class);

		// replace transformation variables in pattern and output format
		regexPattern = getExecutionContext().getVariables().replaceVariables(regexPattern);
		outputFormat = getExecutionContext().getVariables().replaceVariables(outputFormat);

		String sourceString = variables.values().iterator().next().getValueAs(String.class);

		outputFormat = analize(regexPattern, outputFormat, sourceString);

		return outputFormat;
	}

	/**
	 * Performs regex analysis.
	 * 
	 * @param regexPattern the regular expression.
	 * @param outputFormat the output format to gain.
	 * @param sourceString the text to convert.
	 * @return the converted text.
	 * @throws NoResultException in case of missing pattern matching or errors.
	 */
	public static String analize(String regexPattern, String outputFormat, String sourceString)
			throws NoResultException {
		Pattern pattern = Pattern.compile(regexPattern);
		Matcher matcher = pattern.matcher(sourceString);

		StringBuilder result = new StringBuilder();
		int index = 0;
		boolean didMatch = false;
		while (matcher.find()) {
			didMatch = true;
			String tmpOutput = outputFormat;
			int groupCount = matcher.groupCount();
			for (int i = 0; i <= groupCount; i++) {
				String substring = sourceString.substring(matcher.start(i), matcher.end(i));
				tmpOutput = tmpOutput.replaceAll("\\{" + index + "\\}", substring);
				index++;
			}
			result.append(tmpOutput);
			index = 0;
		}

		if (!didMatch) {
			throw new NoResultException("Could not match the pattern.");
		}

		String resultString = result.toString();
		return resultString;
	}
}