samples/dom/DOMFilter.java

/*
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 *
 * This software consists of voluntary contributions made by many
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 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
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package dom;                    

import util.Arguments;

import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


/**
 * A sample DOM filter. This sample program illustrates how to
 * use the Document#getElementsByTagName() method to quickly 
 * and easily locate elements by name.
 *
 * @version $Id$
 */
public class DOMFilter {

    //
    // Constants
    //

    /** Default parser name. */
    private static final String 
    DEFAULT_PARSER_NAME = "dom.wrappers.DOMParser";

    private static boolean setValidation    = false; //defaults
    private static boolean setNameSpaces    = true;
    private static boolean setSchemaSupport = true;
    private static boolean setDeferredDOM   = true;



    //
    // Public static methods
    //

    /** Prints the specified elements in the given document. */
    public static void print(String parserWrapperName, String uri, 
                             String elementName, String attributeName) {

        try {
            // parse document
            DOMParserWrapper parser = 
            (DOMParserWrapper)Class.forName(parserWrapperName).newInstance();

            parser.setFeature( "http://apache.org/xml/features/dom/defer-node-expansion",
                               setDeferredDOM );
            parser.setFeature( "http://xml.org/sax/features/validation", 
                               setValidation );
            parser.setFeature( "http://xml.org/sax/features/namespaces",
                               setNameSpaces );
            parser.setFeature( "http://apache.org/xml/features/validation/schema",
                               setSchemaSupport );


            Document document = parser.parse(uri);

            // get elements that match
            NodeList elements = document.getElementsByTagName(elementName);

            // print nodes
            print(elements, attributeName);
        } catch (Exception e) {
            e.printStackTrace(System.err);
        }

    } // print(String,String,String,String)

    //
    // Private static methods
    //

    /** 
     * Prints the contents of the given element node list. If the given
     * attribute name is non-null, then all of the elements are printed 
     * out
     */
    private static void print(NodeList elements, String attributeName) {

        // is there anything to do?
        if (elements == null) {
            return;
        }

        // print all elements
        if (attributeName == null) {
            int elementCount = elements.getLength();
            for (int i = 0; i < elementCount; i++) {
                Element element = (Element)elements.item(i);
                print(element, element.getAttributes());
            }
        }

        // print elements with given attribute name
        else {
            int elementCount = elements.getLength();
            for (int i = 0; i < elementCount; i++) {
                Element      element    = (Element)elements.item(i);
                NamedNodeMap attributes = element.getAttributes();
                if (attributes.getNamedItem(attributeName) != null) {
                    print(element, attributes);
                }
            }
        }

    } // print(NodeList,String)

    /** Prints the specified element. */
    private static void print(Element element, NamedNodeMap attributes) {

        System.out.print('<');
        System.out.print(element.getNodeName());
        if (attributes != null) {
            int attributeCount = attributes.getLength();
            for (int i = 0; i < attributeCount; i++) {
                Attr attribute = (Attr)attributes.item(i);
                System.out.print(' ');
                System.out.print(attribute.getNodeName());
                System.out.print("=\"");
                System.out.print(normalize(attribute.getNodeValue()));
                System.out.print('"');
            }
        }
        System.out.println('>');

    } // print(Element,NamedNodeMap)

    /** Normalizes the given string. */
    private static String normalize(String s) {
        StringBuffer str = new StringBuffer();

        int len = (s != null) ? s.length() : 0;
        for (int i = 0; i < len; i++) {
            char ch = s.charAt(i);
            switch (ch) {
            case '<': {
                    str.append("&lt;");
                    break;
                }
            case '>': {
                    str.append("&gt;");
                    break;
                }
            case '&': {
                    str.append("&amp;");
                    break;
                }
            case '"': {
                    str.append("&quot;");
                    break;
                }
            case '\r':
            case '\n': {
                    str.append("&#");
                    str.append(Integer.toString(ch));
                    str.append(';');
                    break;
                }
            default: {
                    str.append(ch);
                }
            }
        }

        return str.toString();

    } // normalize(String):String

    //
    // Main
    //

    /** Main program entry point. */
    public static void main(String argv[]) {

        Arguments argopt = new Arguments();
        argopt.setUsage( new String[] 
                         { "usage: java dom.DOMFilter (options) uri ...","",
                             "options:",
                             "  -p name  Specify DOM parser wrapper by name.",
                             "  -e name  Specify element name to search for. Default is \"*\".",
                             "  -a name  Specify attribute name of specified elements.",
                             "  -p name  Specify DOM parser wrapper by name.",
                             "  -n | -N  Turn on/off namespace [default=on]",
                             "  -v | -V  Turn on/off validation [default=on]",
                             "  -s | -S  Turn on/off Schema support [default=on]",
                             "  -d | -D  Turn on/off deferred DOM [default=on]",
                             "  -h       This help screen."} );

        // is there anything to do?
        if (argv.length == 0) {
            argopt.printUsage();
            System.exit(1);
        }

        // vars
        String parserName    = DEFAULT_PARSER_NAME;
        String elementName   = "*"; // all elements
        String attributeName = null;


        /////

        argopt.parseArgumentTokens(argv , new char[] { 'p', 'e', 'a'} );
        int   c;
        String arg = null; 
        while ( ( arg =  argopt.getlistFiles() ) != null ) {
outer:
            while ( (c =  argopt.getArguments()) != -1 ){
                switch (c) {
                case 'v':
                    setValidation = true;
                    break;
                case 'V':
                    setValidation = false;
                    break;
                case 'N':
                    setNameSpaces = false;
                    break;
                case 'n':
                    setNameSpaces = true;
                    break;
                case 'p':
                    parserName = argopt.getStringParameter();
                    break;
                case 'd':
                    setDeferredDOM = true;
                    break;
                case 'D':
                    setDeferredDOM = false;
                    break;
                case 's':
                    setSchemaSupport = true;
                    break;
                case 'S':
                    setSchemaSupport = false;
                    break;
                case 'e':
                    elementName = argopt.getStringParameter();
                    break;
                case 'a':
                    attributeName  = argopt.getStringParameter();
                    break;
                case '?':
                case 'h':
                case '-':
                    argopt.printUsage();
                    System.exit(1);
                    break;
                case -1:
                    break outer;
                default:
                    break;
                }
            }
            // print uri
            System.err.println(arg+':');
            print(parserName, arg, elementName, attributeName);
        }
    } // main(String[])

} // class DOMFilter