PathPattern.java

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package com.sun.jersey.server.impl.uri;

import com.sun.jersey.api.uri.UriPattern;
import com.sun.jersey.api.uri.UriTemplate;
import java.util.Comparator;

/**
 * A URI pattern that is a regular expression generated from a URI path.
 * 
 * @author Paul.Sandoz@Sun.Com
 */
public final class PathPattern extends UriPattern {
    public static final PathPattern EMPTY_PATH = new PathPattern();
    
    /**
     * Defer to comparing the templates associated with the patterns
     */
    static public final Comparator<PathPattern> COMPARATOR = new Comparator<PathPattern>() {
        public int compare(PathPattern o1, PathPattern o2) {
            return UriTemplate.COMPARATOR.compare(o1.template, o2.template);
        }
    };

    /**
     * The regular expression that represents the right hand side of
     * a URI path.
     */
    private static final String RIGHT_HAND_SIDE = "(/.*)?";
        
    private final UriTemplate template;
    
    private PathPattern() {
        super();
        this.template = UriTemplate.EMPTY;
    }
    
    public PathPattern(UriTemplate template) {
        super(postfixWithCapturingGroup(template.getPattern().getRegex()),
            indexCapturingGroup(template.getPattern().getGroupIndexes()));
        
        this.template = template;
    }
    
    public PathPattern(UriTemplate template, String rightHandSide) {
        super(postfixWithCapturingGroup(template.getPattern().getRegex(), rightHandSide),
            indexCapturingGroup(template.getPattern().getGroupIndexes()));

        this.template = template;
    }

    public UriTemplate getTemplate() {
        return template;
    }
    
    private static String postfixWithCapturingGroup(String regex) {
        return postfixWithCapturingGroup(regex, RIGHT_HAND_SIDE);
    }

    private static String postfixWithCapturingGroup(String regex, String rightHandSide) {
        if (regex.endsWith("/"))
            regex = regex.substring(0, regex.length() - 1);

        return regex + rightHandSide;
    }

    private static int[] indexCapturingGroup(int[] indexes) {
        if (indexes.length == 0) return indexes;

        int[] cgIndexes = new int[indexes.length + 1];
        System.arraycopy(indexes, 0, cgIndexes, 0, indexes.length);
        
        cgIndexes[indexes.length] = cgIndexes[indexes.length - 1] + 1;
        return cgIndexes;
    }
}