universe@130: package de.uapcore.lightpit;
universe@130: 
universe@130: import java.util.ArrayList;
universe@130: import java.util.List;
universe@130: 
universe@130: public final class PathPattern {
universe@130: 
universe@130:     private final List<String> nodePatterns;
universe@130:     private final boolean collection;
universe@130: 
universe@130:     /**
universe@130:      * Constructs a new path pattern.
universe@130:      * The special directories . and .. are disallowed in the pattern.
universe@130:      *
universe@130:      * @param pattern
universe@130:      */
universe@130:     public PathPattern(String pattern) {
universe@130:         nodePatterns = parse(pattern);
universe@130:         collection = pattern.endsWith("/");
universe@130:     }
universe@130: 
universe@130:     private List<String> parse(String pattern) {
universe@130: 
universe@130:         var nodes = new ArrayList<String>();
universe@130:         var parts = pattern.split("/");
universe@130: 
universe@130:         for (var part : parts) {
universe@130:             if (part.isBlank()) continue;
universe@130:             if (part.equals(".") || part.equals(".."))
universe@130:                 throw new IllegalArgumentException("Path must not contain '.' or '..' nodes.");
universe@130:             nodes.add(part);
universe@130:         }
universe@130: 
universe@130:         return nodes;
universe@130:     }
universe@130: 
universe@130:     /**
universe@130:      * Matches a path against this pattern.
universe@130:      * The path must be canonical in the sense that no . or .. parts occur.
universe@130:      *
universe@130:      * @param path the path to match
universe@130:      * @return true if the path matches the pattern, false otherwise
universe@130:      */
universe@130:     public boolean matches(String path) {
universe@130:         if (collection ^ path.endsWith("/"))
universe@130:             return false;
universe@130: 
universe@130:         var nodes = parse(path);
universe@130:         if (nodePatterns.size() != nodes.size())
universe@130:             return false;
universe@130: 
universe@130:         for (int i = 0 ; i < nodePatterns.size() ; i++) {
universe@130:             var pattern = nodePatterns.get(i);
universe@130:             var node = nodes.get(i);
universe@130:             if (pattern.startsWith("$"))
universe@130:                 continue;
universe@130:             if (!pattern.equals(node))
universe@130:                 return false;
universe@130:         }
universe@130: 
universe@130:         return true;
universe@130:     }
universe@130: 
universe@130:     /**
universe@130:      * Returns the path parameters found in the specified path using this pattern.
universe@130:      * The return value of this method is undefined, if the patter does not match.
universe@130:      *
universe@130:      * @param path the path
universe@130:      * @return the path parameters, if any, or an empty map
universe@130:      * @see #matches(String)
universe@130:      */
universe@130:     public PathParameters obtainPathParameters(String path) {
universe@130:         var params = new PathParameters();
universe@130: 
universe@130:         var nodes = parse(path);
universe@130: 
universe@130:         for (int i = 0 ; i < Math.min(nodes.size(), nodePatterns.size()) ; i++) {
universe@130:             var pattern = nodePatterns.get(i);
universe@130:             var node = nodes.get(i);
universe@130:             if (pattern.startsWith("$")) {
universe@130:                 params.put(pattern.substring(1), node);
universe@130:             }
universe@130:         }
universe@130: 
universe@130:         return params;
universe@130:     }
universe@130: 
universe@130:     @Override
universe@130:     public int hashCode() {
universe@130:         var str = new StringBuilder();
universe@130:         for (var node : nodePatterns) {
universe@130:             if (node.startsWith("$")) {
universe@130:                 str.append("/$");
universe@130:             } else {
universe@130:                 str.append('/');
universe@130:                 str.append(node);
universe@130:             }
universe@130:         }
universe@130:         if (collection)
universe@130:             str.append('/');
universe@130: 
universe@130:         return str.toString().hashCode();
universe@130:     }
universe@130: 
universe@130:     @Override
universe@130:     public boolean equals(Object obj) {
universe@130:         if (!obj.getClass().equals(PathPattern.class))
universe@130:             return false;
universe@130: 
universe@130:         var other = (PathPattern) obj;
universe@130:         if (collection ^ other.collection || nodePatterns.size() != other.nodePatterns.size())
universe@130:             return false;
universe@130: 
universe@130:         for (int i = 0 ; i < nodePatterns.size() ; i++) {
universe@130:             var left = nodePatterns.get(i);
universe@130:             var right = other.nodePatterns.get(i);
universe@130:             if (left.startsWith("$") && right.startsWith("$"))
universe@130:                 continue;
universe@130:             if (!left.equals(right))
universe@130:                 return false;
universe@130:         }
universe@130: 
universe@130:         return true;
universe@130:     }
universe@130: }