package org.jboss.resteasy.core.registry;

import org.jboss.resteasy.util.PathHelper;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

Author:Bill Burke
Version:$Revision: 1 $
/** * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a> * @version $Revision: 1 $ */
public abstract class Expression implements Comparable<Expression> { // [^?] is in expression to ignore non-capturing group public static final Pattern GROUP = Pattern.compile("[^\\\\]\\([^?]"); protected String pathExpression; protected String regex; protected Pattern pattern; protected List<Group> groups = new ArrayList<Group>(); protected int literalCharacters; protected int numCapturingGroups; protected int numNonDefaultGroups; public Expression(final String segment, final String additionalRegex) { this.pathExpression = segment; CharSequence replacedCurlySegment = PathHelper.replaceEnclosedCurlyBracesCS(segment); literalCharacters = PathHelper.URI_PARAM_PATTERN.matcher(replacedCurlySegment).replaceAll("").length(); String[] split = PathHelper.URI_PARAM_PATTERN.split(replacedCurlySegment); Matcher withPathParam = PathHelper.URI_PARAM_PATTERN.matcher(replacedCurlySegment); int i = 0; StringBuffer buffer = new StringBuffer(); if (i < split.length) buffer.append(Pattern.quote(split[i++])); int groupNumber = 1; while (withPathParam.find()) { String name = withPathParam.group(1); buffer.append("("); if (withPathParam.group(3) == null) { buffer.append("[^/]+"); groups.add(new Group(groupNumber++, name, true)); } else { String expr = withPathParam.group(3); expr = PathHelper.recoverEnclosedCurlyBraces(expr); buffer.append(expr); numNonDefaultGroups++; groups.add(new Group(groupNumber++, name)); groupNumber += groupCount(expr); } buffer.append(")"); if (i < split.length) buffer.append(Pattern.quote(split[i++])); } if (additionalRegex != null) buffer.append(additionalRegex); regex = buffer.toString(); pattern = Pattern.compile(getRegex()); } public int compareTo(Expression expression) { // as per spec sort first by literal characters, then numCapturing groups, then num non-default groups if (literalCharacters > expression.literalCharacters) return -1; if (literalCharacters < expression.literalCharacters) return 1; if (numCapturingGroups > expression.numCapturingGroups) return -1; if (numCapturingGroups < expression.numCapturingGroups) return 1; if (numNonDefaultGroups > expression.numNonDefaultGroups) return -1; if (numNonDefaultGroups < expression.numNonDefaultGroups) return 1; return 0; }
Find the number of groups in the regular expression don't count escaped '('.
Params:
  • regex – regular expression
Returns:number of groups
/** * Find the number of groups in the regular expression * don't count escaped '('. * * @param regex regular expression * @return number of groups */
protected static int groupCount(String regex) { regex = " " + regex; // add a space because GROUP regex trans to match a non-preceding slash. // if the grouping characters in the range block ignore them. int idxOpen = regex.indexOf('['); if (idxOpen != -1) { int idxClose = regex.indexOf(']', idxOpen); if (idxClose != -1) { regex = regex.substring(0, idxOpen) + regex.substring(idxClose + 1); } } Matcher matcher = GROUP.matcher(regex); int groupCount = 0; while (matcher.find()) groupCount++; return groupCount; } public int getNumGroups() { return groups.size(); } public String getRegex() { return regex; } public String getPathExpression() { return pathExpression; } public Pattern getPattern() { return pattern; } protected static class Group { int group; String name; boolean storePathSegment; protected Group(final int group, final String name) { this.group = group; this.name = name; } protected Group(final int group, final String name, final boolean storePathSegment) { this.group = group; this.name = name; this.storePathSegment = storePathSegment; } } }