org.databene.commons.math.IntervalParser Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of databene-commons Show documentation

'databene commons' is an open source Java library by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

There is a newer version: 1.0.11

Show newest version

/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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.databene.commons.math;

import java.text.ParsePosition;
import java.util.Comparator;

import org.databene.commons.ParseException;
import static org.databene.commons.ParseUtil.skipWhiteSpace;
import org.databene.commons.Parser;

/**
 * Parses an {@link Interval} generically using an endpoint parser and an endpoint comparator.
 * The endpoint parser has to be able to parse the interval endpoint values.
 * Created: 10.03.2011 15:33:01
 * @param  the type of the bounds that define the interval
 * @since 0.5.8
 * @author Volker Bergmann
 */
public class IntervalParser extends Parser> {

	private Parser endpointParser;
	private Comparator endpointComparator;

	public static  Interval parse(String text, Parser endpointParser, Comparator endpointComparator) {
		return new IntervalParser(endpointParser, endpointComparator).parseObject(text, new ParsePosition(0));
	}
	
	public IntervalParser(Parser endPointParser, Comparator endpointComparator) {
		this.endpointParser = endPointParser;
		this.endpointComparator = endpointComparator;
	}

	@Override
	public Interval parseObject(String text, ParsePosition pos) throws ParseException {
		skipWhiteSpace(text, pos);

		// parse left bracket
		boolean minInclusive;
		char c = text.charAt(pos.getIndex());
		switch (c) {
			case '[' : minInclusive = true; break;
			case ']' : minInclusive = false; break;
			default  : throw new ParseException("Expected '[' or ']', found: " + c, text);
		}
		pos.setIndex(pos.getIndex() + 1);
		skipWhiteSpace(text, pos);
		
		// parse lower endpoint
		E min = endpointParser.parseObject(text, pos);
		skipWhiteSpace(text, pos);

		// parse comma
		c = text.charAt(pos.getIndex());
		if (c != ',')
			throw new ParseException("Expected ',', found '" + c + "'", text);
		pos.setIndex(pos.getIndex() + 1);
		skipWhiteSpace(text, pos);
		
		// parse upper endpoint
		E max = endpointParser.parseObject(text, pos);
		skipWhiteSpace(text, pos);
		
		// parse right bracket
		boolean maxInclusive;
		c = text.charAt(pos.getIndex());
		switch (c) {
			case ']' : maxInclusive = true; break;
			case '[' : maxInclusive = false; break;
			default  : throw new ParseException("Expected '[' or ']', found: " + c, text);
		}
		pos.setIndex(pos.getIndex() + 1);
		skipWhiteSpace(text, pos);
		
		return new Interval(min, minInclusive, max, maxInclusive, endpointComparator);
	}

}