X-Git-Url: http://www2.svjatoslav.eu/gitweb/?p=svjatoslav_commons.git;a=blobdiff_plain;f=src%2Fmain%2Fjava%2Feu%2Fsvjatoslav%2Fcommons%2Fstring%2Ftokenizer%2FTokenizer.java;h=14554beb886acffc4e638b31b5e50c49cb6ada51;hp=899f8c4d7ed8fe0da58a944a38f52d910957cc1f;hb=b1ffc7025cc976821987469570f07a7298ea16c9;hpb=0b3d733f44e95ee093985531072a1f8965f7c09a diff --git a/src/main/java/eu/svjatoslav/commons/string/tokenizer/Tokenizer.java b/src/main/java/eu/svjatoslav/commons/string/tokenizer/Tokenizer.java index 899f8c4..14554be 100755 --- a/src/main/java/eu/svjatoslav/commons/string/tokenizer/Tokenizer.java +++ b/src/main/java/eu/svjatoslav/commons/string/tokenizer/Tokenizer.java @@ -1,52 +1,68 @@ /* - * Svjatoslav Commons - shared library of common functionality. - * Copyright ©2012-2017, Svjatoslav Agejenko, svjatoslav@svjatoslav.eu - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of version 3 of the GNU Lesser General Public License - * or later as published by the Free Software Foundation. + * Svjatoslav Commons - shared library of common functionality. Author: Svjatoslav Agejenko. + * This project is released under Creative Commons Zero (CC0) license. */ - package eu.svjatoslav.commons.string.tokenizer; import java.util.ArrayList; import java.util.List; import java.util.Stack; +import java.util.regex.Matcher; +import java.util.stream.Stream; -import static eu.svjatoslav.commons.string.tokenizer.Terminator.TerminationStrategy.DROP; +import static eu.svjatoslav.commons.string.tokenizer.Terminator.TerminationStrategy.PRESERVE; +import static java.lang.System.out; public class Tokenizer { - final Stack tokenIndexes = new Stack<>(); + /** + * Stack of token indexes. This allows to walk back in history and un-consume the token. + */ + private final Stack tokenIndexes = new Stack<>(); + + /** + * Terminators that will be searched for by given tokenizer within given source string. + */ private final List terminators = new ArrayList<>(); - private String source; + + private String source; // string to be tokenized + private int currentIndex = 0; public Tokenizer(final String source) { this.source = source; } - public Tokenizer(){} + public Tokenizer() { + } - public Tokenizer setSource(String source){ + public Tokenizer setSource(String source) { this.source = source; currentIndex = 0; + tokenIndexes.clear(); return this; } - public Tokenizer addTerminator(final String startSequence, - final Terminator.TerminationStrategy terminationStrategy) { - terminators.add(new Terminator(startSequence, terminationStrategy)); - return this; + public Terminator addTerminator(final Terminator.TerminationStrategy terminationStrategy, String regexp) { + Terminator terminator = new Terminator(terminationStrategy, regexp,null); + terminators.add(terminator); + return terminator; } - public Tokenizer addTerminator(final String startSequence, - final String endSequence, final Terminator.TerminationStrategy terminationStrategy) { - terminators.add(new Terminator(startSequence, endSequence, terminationStrategy)); - return this; + public Terminator addTerminator(final Terminator.TerminationStrategy terminationStrategy, + String regexp, String group) { + Terminator terminator = new Terminator(terminationStrategy, regexp,group); + terminators.add(terminator); + return terminator; + } + + + public Terminator addTerminator(Terminator terminator) { + terminators.add(terminator); + return terminator; } - public void expectNextToken(final String value) + public void expectAndConsumeNextStringToken(final String value) throws InvalidSyntaxException { final TokenizerMatch match = getNextToken(); if (!value.equals(match.token)) @@ -54,49 +70,79 @@ public class Tokenizer { + "\" but got \"" + match.token + "\" instead."); } + public TokenizerMatch expectAndConsumeNextTerminatorToken(Terminator terminator) + throws InvalidSyntaxException { + final TokenizerMatch match = getNextToken(); + + if (match.terminator != terminator) + throw new InvalidSyntaxException("Expected terminator \"" + terminator + + "\" but got \"" + match.terminator + "\" instead."); + + return match; + } + + + /** + * @return next @TokenizerMatch or null if end of input is reached. + */ public TokenizerMatch getNextToken() { tokenIndexes.push(currentIndex); - final StringBuilder result = new StringBuilder(); + + StringBuilder tokenAccumulator = new StringBuilder(); while (true) { - if (currentIndex >= source.length()) - return null; - - boolean accumulateCurrentChar = true; - - for (final Terminator terminator : terminators) - if (sequenceMatches(terminator.startSequence)) - - if (terminator.termination == DROP) { - currentIndex += terminator.startSequence.length(); - - if (terminator.endSequence != null) - skipUntilSequence(terminator.endSequence); - - if (result.length() > 0) - return new TokenizerMatch(result.toString(), - terminator); - else { - accumulateCurrentChar = false; - break; - } - } else if (result.length() > 0) - return new TokenizerMatch(result.toString(), terminator); - else { - currentIndex += terminator.startSequence.length(); - return new TokenizerMatch(terminator.startSequence, - terminator); - } - - if (accumulateCurrentChar) { - result.append(source.charAt(currentIndex)); + + if (currentIndex >= source.length()) { // reached end of input + if (hasAccumulatedToken(tokenAccumulator)) + return new TokenizerMatch(tokenAccumulator.toString(), null, null, this); + else + return null; + } + + TokenizerMatch matchResult = findTerminatorMatch(); + if (matchResult == null) { + tokenAccumulator.append(source.charAt(currentIndex)); currentIndex++; + continue; + } + + if (matchResult.terminator.termination == PRESERVE) { + if (hasAccumulatedToken(tokenAccumulator)) + return new TokenizerMatch(tokenAccumulator.toString(), null, null, this); + + currentIndex = matchResult.matcher.end(); + return matchResult; + } else { + currentIndex = matchResult.matcher.end(); + + if (hasAccumulatedToken(tokenAccumulator)) + return new TokenizerMatch(tokenAccumulator.toString(), null, null, this); } } + } + + public TokenizerMatch findTerminatorMatch(){ + for (Terminator terminator : terminators) + if (terminator.active) { + Matcher match = terminator.match(source, currentIndex); + if (match.find()) { + String token = source.substring(match.start(), match.end()); + return new TokenizerMatch(token, terminator, match, this); + } + } + return null; + } + + private boolean hasAccumulatedToken(StringBuilder tokenAccumulator) { + return tokenAccumulator.length() > 0; + } + public boolean hasMoreContent() { + if (source == null) return false; + return currentIndex < source.length(); } - public boolean consumeIfNextToken(final String token) { + public boolean consumeIfNextToken(final String token) throws InvalidSyntaxException { if (token.equals(getNextToken().token)) return true; @@ -104,35 +150,45 @@ public class Tokenizer { return false; } - public boolean sequenceMatches(final String sequence) { - if ((currentIndex + sequence.length()) > source.length()) - return false; + public TokenizerMatch peekNextToken() throws InvalidSyntaxException { + TokenizerMatch result = getNextToken(); + unreadToken(); + return result; + } - for (int i = 0; i < sequence.length(); i++) - if (sequence.charAt(i) != source.charAt(i + currentIndex)) - return false; + public boolean peekIsOneOf(String... possibilities) throws InvalidSyntaxException { + String nextToken = peekNextToken().token; + return Stream.of(possibilities).anyMatch(possibility -> possibility.equals(nextToken)); + } - return true; + public void peekExpectNoneOf(String... possibilities) throws InvalidSyntaxException { + if (peekIsOneOf(possibilities)) + throw new InvalidSyntaxException("Not expected \"" + peekNextToken().token + "\" here."); } - public void skipUntilDataEnd() { - tokenIndexes.push(currentIndex); - currentIndex = source.length(); + public void unreadToken() { + currentIndex = tokenIndexes.pop(); } - public void skipUntilSequence(final String sequence) { - while (currentIndex < source.length()) { - if (sequenceMatches(sequence)) { - currentIndex += sequence.length(); - return; - } + /** + * For debugging + */ + public void enlistRemainingTokens(){ + int redTokenCount = 0; - currentIndex++; + while (hasMoreContent()) { + out.println(getNextToken().toString()); + redTokenCount++; } + + // restore pointer to original location + for (int i = 0; i< redTokenCount; i++ ) unreadToken(); } - public void unreadToken() { - currentIndex = tokenIndexes.pop(); + + public void skipUntilDataEnd() { + tokenIndexes.push(currentIndex); + currentIndex = source.length(); } }