org.semanticweb.yars.turtle.Prologue Maven / Gradle / Ivy

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.semanticweb.yars.turtle;

import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.semanticweb.yars.nx.Resource;

/**
 * Keep track of prefixes and base URI.
 * 
 * @author aharth
 */
public class Prologue {
	final static Logger _log = Logger.getLogger(Prologue.class.getName());

	Map _prefixes;
    URI _baseURI = null;

	public Prologue() {
		_prefixes = new HashMap();
	}

	public void setPrefix(String prefix, String s) {
		// strip <>
		s = s.substring(1, s.length()-1);

		// empty prefix
		if (s.length() == 0) {
			s = _baseURI.toString();
		}

    	URI u = URI.create(s);
        _log.log(Level.FINE, "Creating resource {0}, absolute? {1}", new Object[] { s, u.isAbsolute() });

    	if (!u.isAbsolute()) {
    		_log.log(Level.FINE, "Resolving {0} relative to {1}", new Object[] { u, getBaseURI() } );
    		u = getBaseURI().resolve(u);
    	}

		_log.log(Level.FINE, "@prefix {0}: {1}", new Object[] { prefix, u.toString() } );
		_prefixes.put(prefix, u.toString());
	}

	public String expandPrefix(String prefix) {
		return _prefixes.get(prefix);
	}

	/**
     * @return baseURI, if set.
     */
    public URI getBaseURI() {
    	return _baseURI;
    }

    /**
     * @param baseURI The baseURI to set.
     */
    public void setBaseURI(Resource base) {
        _baseURI = URI.create(base.getLabel());
        if (!_baseURI.isAbsolute()) {
        	throw new IllegalArgumentException("Base URI " + base + " needs to be absolute!");
        }
    }

    public void setBase(URI base) {
        _baseURI = base;
        if (!_baseURI.isAbsolute()) {
        	throw new IllegalArgumentException("Base URI " + base + " needs to be absolute!");
        }
    }

}