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This project contains some of the configurable modules used within the Heritrix application to crawl the web. The modules in this project can be used in applications other than Heritrix, however.

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/*
 *  This file is part of the Heritrix web crawler (crawler.archive.org).
 *
 *  Licensed to the Internet Archive (IA) by one or more individual 
 *  contributors. 
 *
 *  The IA licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.archive.modules.extractor;


/**
 * The kind of "hop" from one URI to another.  Each hop type can be 
 * represented by a single character; strings of these characters can 
 * appear in logs.  Eg, "LLLX" means that a URI was three normal links from
 * a seed, and then one speculative link.
 * 
 * @author pjack
 */
public enum Hop {

    /** Navigation links, like A/@HREF. */
    NAVLINK('L'),
    
    /** Implied prerequisite links, like dns or robots. */
    PREREQ('P'),
    
    /** Embedded links necessary to render the page, like IMG/@SRC. */
    EMBED('E'),
    
    /** 
     * Speculative/aggressively extracted links, perhaps embed or nav, 
     * as in javascript.  
     */
    SPECULATIVE('X'),
    
    /** 
     * Referral/redirect links, like header 'Location:' on a 301/302 response. 
     */
    REFER('R'),

    /** 
     * Inferred/implied links -- not necessarily literally in the source 
     * material, but deduced by convention.
     */
    INFERRED('I'),
    
    /** Synthesized form-submit */ 
    SUBMIT('S');
    
    /** The hop character for logs. */
    private char hopChar;
    protected String hopString; 
    
    /**
     * Constructor.
     * 
     * @param hopChar  the hop character for logs
     */
    private Hop(char hopChar) {
        this.hopChar = hopChar;
        this.hopString = ""+hopChar;
    }

    
    /**
     * Returns a hop character suitable for display in logs.
     * 
     * @return   the hop character
     */
    public char getHopChar() {
        return hopChar;
    }


    public String getHopString() {
        return hopString;
    }
}