PrologPostProcessor.java

package org.linkality.xacmlanalysr;

import java.io.File;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Applies transformation to the Prolog file that has been generated by the
 * OWL2Prolog converter.
 * <p>
 * The post-processor takes care of re-formatting terms in correct Prolog syntax
 * and adds required functions.
 * 
 * @author Julian Schuette
 * 
 */
public class PrologPostProcessor {
	private static PrologPostProcessor instance;

	private PrologPostProcessor() {
		super();
	}

	/**
	 * Gets a singleton instance.
	 * 
	 * @return
	 */
	public static PrologPostProcessor getInstance() {
		if (instance == null) {
			instance = new PrologPostProcessor();
		}
		return instance;
	}

	/**
	 * Applies post-processing to a Prolog file.
	 * 
	 * @param xacmlPrologFile The prolog file.
	 */
	public void execute(File xacmlPrologFile) {
		try {
			String content = Utils.readFileAsString(xacmlPrologFile);
			// content = content.replace("'hydra#ANY'", "_");
			content = content.replace("http://www.hydramiddleware.eu/xacml#", "hydra#");
			Pattern pattern = Pattern.compile("(literal\\(type\\([^,]+,[\\s]+)(.+[^\\)])(\\)\\))");
			Matcher matcher = pattern.matcher(content);
			content = matcher.replaceAll("$2");

			content = content
					+ "\n"
					+ "getExplanation(Effect, ResourceValue, ActionValue, SubjectValue, EnvironmentValue, Result):-setof([X, R, Effect, ResourceValue, ActionValue, SubjectValue, EnvironmentValue], "
					+ "(('hydra#hasEffect'(X,Effect) ; ('hydra#hasRule'(X,R),'hydra#hasEffect'(R,Effect))), 'hydra#hasTarget'(X, T), "
					+ "('hydra#hasResource'(T, 'hydra#ANY')->(ResourceValue='hydra#ANY')		;('hydra#hasResource'(T, Resource), 'hydra#hasMatch'(Resource, ResourceMatch), 'hydra#hasAttributeValue'(ResourceMatch, ResourceValue))),	"
					+ "('hydra#hasAction'(T, 'hydra#ANY')->(ActionValue='hydra#ANY') 			;('hydra#hasAction'(T, Action), 'hydra#hasMatch'(Action, ActionMatch), 'hydra#hasAttributeValue'(ActionMatch, ActionValue))),	"
					+ "('hydra#hasSubject'(T, 'hydra#ANY')->(SubjectValue='hydra#ANY')		;('hydra#hasSubject'(T, Subject), 'hydra#hasMatch'(Subject, SubjectMatch), 'hydra#hasAttributeValue'(SubjectMatch, SubjectValue))),	"
					+ "('hydra#hasEnvironment'(T, 'hydra#ANY')->(EnvironmentValue='hydra#ANY');('hydra#hasEnvironment'(T, Environment), 'hydra#hasMatch'(Environment, EnvironmentMatch), 'hydra#hasAttributeValue'(EnvironmentMatch, EnvironmentValue)))), Result).	";

			content = content
					+ "\n"
					+ "getRequiredAttributes(Effect, ResourceValue, ActionValue, SubjectValue, EnvironmentValue, Result):-setof([ResourceValue, SubjectValue, EnvironmentValue], "
					+ "(('hydra#hasEffect'(X,Effect) ; ('hydra#hasRule'(X,R),'hydra#hasEffect'(R,Effect))), 'hydra#hasTarget'(X, T), "
					+ "('hydra#hasResource'(T, 'hydra#ANY')->(ResourceValue='hydra#ANY')		;('hydra#hasResource'(T, Resource), 'hydra#hasMatch'(Resource, ResourceMatch), 'hydra#hasAttributeValue'(ResourceMatch, ResourceValue))),	"
					+ "('hydra#hasAction'(T, 'hydra#ANY')->(ActionValue='hydra#ANY') 			;('hydra#hasAction'(T, Action), 'hydra#hasMatch'(Action, ActionMatch), 'hydra#hasAttributeValue'(ActionMatch, ActionValue))),	"
					+ "('hydra#hasSubject'(T, 'hydra#ANY')->(SubjectValue='hydra#ANY')		;('hydra#hasSubject'(T, Subject), 'hydra#hasMatch'(Subject, SubjectMatch), 'hydra#hasAttributeValue'(SubjectMatch, SubjectValue))),	"
					+ "('hydra#hasEnvironment'(T, 'hydra#ANY')->(EnvironmentValue='hydra#ANY');('hydra#hasEnvironment'(T, Environment), 'hydra#hasMatch'(Environment, EnvironmentMatch), 'hydra#hasAttributeValue'(EnvironmentMatch, EnvironmentValue)))), Result).	";

			Utils.writeStringToFile(content, xacmlPrologFile);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}