1 /* 2 [The "BSD license"] 3 Copyright (c) 2012 Terence Parr 4 Copyright (c) 2012 Sam Harwell 5 All rights reserved. 6 7 Redistribution and use in source and binary forms, with or without 8 modification, are permitted provided that the following conditions 9 are met: 10 1. Redistributions of source code must retain the above copyright 11 notice, this list of conditions and the following disclaimer. 12 2. Redistributions in binary form must reproduce the above copyright 13 notice, this list of conditions and the following disclaimer in the 14 documentation and/or other materials provided with the distribution. 15 3. The name of the author may not be used to endorse or promote products 16 derived from this software without specific prior written permission. 17 18 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 package org.antlr.runtime.tree; 30 31 /** 32 * 33 * @author Sam Harwell 34 */ 35 public interface PositionTrackingStream<T> { 36 37 /** 38 * Returns an element containing concrete information about the current 39 * position in the stream. 40 * 41 * @param allowApproximateLocation if {@code false}, this method returns 42 * {@code null} if an element containing exact information about the current 43 * position is not available 44 */ getKnownPositionElement(boolean allowApproximateLocation)45 T getKnownPositionElement(boolean allowApproximateLocation); 46 47 /** 48 * Determines if the specified {@code element} contains concrete position 49 * information. 50 * 51 * @param element the element to check 52 * @return {@code true} if {@code element} contains concrete position 53 * information, otherwise {@code false} 54 */ hasPositionInformation(T element)55 boolean hasPositionInformation(T element); 56 57 } 58