org.twinkql.result.DefaultMatchExpressionParser.java Source code

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Here is the source code for org.twinkql.result.DefaultMatchExpressionParser.java

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/*
 * Copyright: (c) 2004-2012 Mayo Foundation for Medical Education and 
 * Research (MFMER). All rights reserved. MAYO, MAYO CLINIC, and the
 * triple-shield Mayo logo are trademarks and service marks of MFMER.
 *
 * Except as contained in the copyright notice above, or as used to identify 
 * MFMER as the author of this software, the trade names, trademarks, service
 * marks, or product names of the copyright holder shall not be used in
 * advertising, promotion or otherwise in connection with this software without
 * prior written authorization of the copyright holder.
 *
 * 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 org.twinkql.result;

import java.lang.reflect.Method;
import java.util.regex.Pattern;

import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Component;
import org.springframework.util.ReflectionUtils;

import com.hp.hpl.jena.query.QuerySolution;
import com.hp.hpl.jena.rdf.model.RDFNode;

/**
 * The Class DefaultMatchExpressionParser.
 *
 * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
 */
@Component
public class DefaultMatchExpressionParser implements MatchExpressionParser {

    private static final String DOT = ".";
    private static final String METHOD = "()";
    private static final String EQUALS = "=";

    private Pattern methodPattern = Pattern.compile("^.*\\..*\\(\\)$");
    private Pattern equalsPattern = Pattern.compile("^.*=.*$");

    /* (non-Javadoc)
     * @see edu.mayo.twinkql.result.MatchExpressionParser#parseMatchExpression(java.lang.String)
     */
    public MatchExpression parseMatchExpression(String query) {
        if (this.methodPattern.matcher(query).matches()) {
            return this.parseRdfNodeMethod(query);
        }
        if (this.equalsPattern.matcher(query).matches()) {
            return this.parseEquals(query);
        }

        throw new MatchConditionParseException(query);
    }

    /**
     * Parses the rdf node method.
     *
     * @param query the query
     * @return the match expression
     */
    private MatchExpression parseRdfNodeMethod(String query) {
        String[] queryParts = StringUtils.split(query, DOT);

        if (queryParts == null || queryParts.length != 2) {
            throw new MatchConditionParseException(query);
        }

        return new JenaRdfNodeMatchExpression(StringUtils.remove(queryParts[0], '?').trim(),
                StringUtils.removeEnd(queryParts[1].trim(), METHOD));
    }

    /**
     * Parses the equals.
     *
     * @param query the query
     * @return the match expression
     */
    private MatchExpression parseEquals(String query) {
        String[] queryParts = StringUtils.split(query, EQUALS);

        if (queryParts == null || queryParts.length != 2) {
            throw new MatchConditionParseException(query);
        }

        return new EqualsMatchExpression(StringUtils.remove(queryParts[0], '?').trim(), queryParts[1].trim());
    }

    /**
     * The Class JenaRdfNodeMatchExpression.
     *
     * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
     */
    public class JenaRdfNodeMatchExpression implements MatchExpression {

        private String var;
        private String method;

        /**
         * Instantiates a new jena rdf node match expression.
         *
         * @param var the var
         * @param method the method
         */
        private JenaRdfNodeMatchExpression(String var, String method) {
            super();
            this.var = var;
            this.method = method;
        }

        /* (non-Javadoc)
         * @see edu.mayo.twinkql.result.MatchExpression#isMatch(com.hp.hpl.jena.query.QuerySolution)
         */
        public boolean isMatch(QuerySolution querySolution) {
            RDFNode rdfNode = querySolution.get(this.var);

            Method method = ReflectionUtils.findMethod(RDFNode.class, this.method);

            return (Boolean) ReflectionUtils.invokeMethod(method, rdfNode);
        }

    }

    /**
     * The Class EqualsMatchExpression.
     *
     * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
     */
    public static class EqualsMatchExpression implements MatchExpression {

        private String var;
        private String matchValue;

        /**
         * Instantiates a new equals match expression.
         *
         * @param var the var
         * @param matchValue the match value
         */
        private EqualsMatchExpression(String var, String matchValue) {
            super();
            this.var = var;
            this.matchValue = matchValue;
        }

        /* (non-Javadoc)
         * @see edu.mayo.twinkql.result.MatchExpression#isMatch(com.hp.hpl.jena.query.QuerySolution)
         */
        public boolean isMatch(QuerySolution querySolution) {
            RDFNode rdfNode = querySolution.get(this.var);

            if (!rdfNode.isURIResource()) {
                throw new MatchConditionParseException(this.var + " when applied does not result in a URI Node.");
            }

            return rdfNode.asNode().getURI().equals(this.matchValue);
        }

    }

    /**
     * The Class MatchConditionParseException.
     *
     * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
     */
    public static class MatchConditionParseException extends RuntimeException {

        private static final long serialVersionUID = -4164684389047290459L;

        /**
         * Instantiates a new match condition parse exception.
         *
         * @param query the query
         */
        private MatchConditionParseException(String query) {
            super("Query: " + query + " is not a valid match expression");
        }
    }

}