SimpleDomainExtractor.java

/**
 * This file is part of General Entity Annotator Benchmark.
 *
 * General Entity Annotator Benchmark is free software: you can redistribute it and/or modify
 * it 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.
 *
 * General Entity Annotator Benchmark 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with General Entity Annotator Benchmark.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.aksw.gerbil.semantic.sameas.impl;

/**
 * Very simple approach to find the domain inside a given URI.
 * 
 * @author Michael Röder (roeder@informatik.uni-leipzig.de)
 *
 */
public class SimpleDomainExtractor {

    private static final String DOMAIN_PREFIX = "://";
    private static final int DOMAIN_PREFIX_LENGTH = DOMAIN_PREFIX.length();

    public static String extractDomain(String uri) {
        if (uri == null) {
            return null;
        }
        // get the start position of the domain
        int startPos = uri.indexOf(DOMAIN_PREFIX);
        if (startPos < 0) {
            startPos = 0;
        } else {
            startPos += DOMAIN_PREFIX_LENGTH;
        }
        // find the end position of the String
        char chars[] = uri.toCharArray();
        for (int i = startPos; i < chars.length; ++i) {
            switch (chars[i]) {
            // if this is a character that is not part of the domain, anymore
            case '/':
            case ':': {
                return uri.substring(startPos, i);
            }
            default: {
                // nothing to do
            }
            }
        }
        // we couldn't find the end, but maybe we have found a start
        return uri.substring(startPos);
    }
}