graph/store/PathPattern.java

   1 package org.simantics.graph.store;
   2
   3 import gnu.trove.set.hash.THashSet;
   4
   5 import java.util.regex.Pattern;
   6
   7 import org.simantics.graph.query.Path;
   8 import org.simantics.graph.query.PathChild;
   9 import org.simantics.graph.query.Paths;
  10
  11 public class PathPattern {
  12
  13         private static PathPattern EMPTY_PATTERN = new PathPattern(null, null);
  14
  15         Path prefix;
  16         Pattern suffix;
  17
  18         private PathPattern(Path prefix, Pattern suffix) {
  19                 this.prefix = prefix;
  20                 this.suffix = suffix;
  21         }
  22
  23         public static PathPattern compile(String pattern) {
  24                 pattern = stripPatternPrefix(pattern);
  25                 if(pattern == null)
  26                         return EMPTY_PATTERN;
  27                 String[] parts = pattern.split("/");
  28
  29                 Path path = Paths.Root;
  30                 for(int i=0;i<parts.length;++i) {
  31                         String part = parts[i];
  32                         if(containsWildcards(part)) {
  33                                 StringBuilder b = new StringBuilder(pattern.length());
  34                                 for(;i<parts.length;++i) {
  35                                         b.append('/');
  36                                         b.append(parts[i]);
  37                                 }
  38                                 return new PathPattern(path, compileGlobPattern(b.toString()));
  39                         }
  40                         else
  41                                 path = new PathChild(part, path);
  42                 }
  43
  44                 return new PathPattern(path, null);
  45         }
  46
  47         private static String patternStart = "http://";
  48         private static String stripPatternPrefix(String pattern) {
  49                 for(int i=0;i<patternStart.length();++i) {
  50                         if(pattern.length() <= i)
  51                                 return null;
  52                         char c = pattern.charAt(i);
  53                         if(c == '*')
  54                                 return pattern.substring(i);
  55                         if(c != patternStart.charAt(i) && c != '?')
  56                                 return null;
  57                 }
  58                 return pattern.substring(patternStart.length());
  59         }
  60
  61         private static boolean containsWildcards(String pattern) {
  62                 return pattern.contains("*") || pattern.contains("?");
  63         }
  64
  65         private static Pattern compileGlobPattern(String pattern) {
  66                 int length = pattern.length();
  67                 StringBuilder b = new StringBuilder(2*length);
  68                 b.append("\\Q");
  69                 for(int i=0;i<length;++i) {
  70                         char c = pattern.charAt(i);
  71                         switch(c) {
  72                         case '*':
  73                                 b.append("\\E.*\\Q");
  74                                 break;
  75                         case '?':
  76                                 b.append("\\E.\\Q");
  77                                 break;
  78                         case '\\':
  79                                 ++i;
  80                                 if(i < length) {
  81                                         c = pattern.charAt(i);
  82                                         if(c == '\\' && i+1 < length && pattern.charAt(i+1) == 'E') {
  83                                                 ++i;
  84                                                 b.append("\\E\\\\E\\Q");
  85                                         }
  86                                         else if(c == '*' || c == '?')
  87                                                 b.append(c);
  88                                         else {
  89                                                 b.append('\\');
  90                                                 b.append(c);
  91                                         }
  92                                 }
  93                                 break;
  94                         default:
  95                                 b.append(c);
  96                         }
  97                 }
  98                 b.append("\\E");
  99                 return Pattern.compile(b.toString());
 100         }
 101
 102         @Override
 103         public String toString() {
 104                 return "(" + prefix + ", " + suffix + ")";
 105         }
 106
 107         public void search(IdentityStore store, THashSet<Path> result) {
 108                 int id = store.pathToId(prefix);
 109                 if(id == -1)
 110                         return;
 111                 store.findChildren(id, prefix, "", suffix, result);
 112         }
 113
 114         public static void main(String[] args) {
 115                 System.out.println(compile("http://www.simantics.org/*/foo"));
 116         }
 117 }