samples/dom/GetElementsByTagName.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999, 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package dom;

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;

import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.SAXParseException;

/**
 * A sample DOM filter. This sample program illustrates how to
 * use the Document#getElementsByTagName() method to quickly
 * and easily locate elements by name.
 *
 * @author Jeffrey Rodriguez, IBM
 * @author Andy Clark, IBM
 *
 * @version $Id$
 */
public class GetElementsByTagName {

    //
    // Constants
    //

    // feature ids

    /** Namespaces feature id (http://xml.org/sax/features/namespaces). */
    protected static final String NAMESPACES_FEATURE_ID = "http://xml.org/sax/features/namespaces";

    /** Validation feature id (http://xml.org/sax/features/validation). */
    protected static final String VALIDATION_FEATURE_ID = "http://xml.org/sax/features/validation";

    /** Schema validation feature id (http://apache.org/xml/features/validation/schema). */
    protected static final String SCHEMA_VALIDATION_FEATURE_ID = "http://apache.org/xml/features/validation/schema";

    /** Schema full checking feature id (http://apache.org/xml/features/validation/schema-full-checking). */
    protected static final String SCHEMA_FULL_CHECKING_FEATURE_ID = "http://apache.org/xml/features/validation/schema-full-checking";

    // default settings

    /** Default parser name (dom.wrappers.Xerces). */
    protected static final String DEFAULT_PARSER_NAME = "dom.wrappers.Xerces";

    /** Default element name (*). */
    protected static final String DEFAULT_ELEMENT_NAME = "*";

    /** Default namespaces support (true). */
    protected static final boolean DEFAULT_NAMESPACES = true;

    /** Default validation support (false). */
    protected static final boolean DEFAULT_VALIDATION = false;

    /** Default Schema validation support (false). */
    protected static final boolean DEFAULT_SCHEMA_VALIDATION = false;

    /** Default Schema full checking support (false). */
    protected static final boolean DEFAULT_SCHEMA_FULL_CHECKING = false;

    //
    // Public static methods
    //

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

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

        // 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(out, 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(out, element, attributes);
                }
            }
        }

    } // print(PrintWriter,Document,String,String)

    //
    // Protected static methods
    //

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

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

    } // print(PrintWriter,Element,NamedNodeMap)

    /** Normalizes the given string. */
    protected 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[]) {

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

        // variables
        Counter counter = new Counter();
        PrintWriter out = new PrintWriter(System.out);
        ParserWrapper parser = null;
        String elementName = DEFAULT_ELEMENT_NAME;
        String attributeName = null;
        boolean namespaces = DEFAULT_NAMESPACES;
        boolean validation = DEFAULT_VALIDATION;
        boolean schemaValidation = DEFAULT_SCHEMA_VALIDATION;
        boolean schemaFullChecking = DEFAULT_SCHEMA_FULL_CHECKING;

        // process arguments
        for (int i = 0; i < argv.length; i++) {
            String arg = argv[i];
            if (arg.startsWith("-")) {
                String option = arg.substring(1);
                if (option.equals("p")) {
                    // get parser name
                    if (++i == argv.length) {
                        System.err.println("error: Missing argument to -p option.");
                    }
                    String parserName = argv[i];

                    // create parser
                    try {
                        parser = (ParserWrapper)Class.forName(parserName).newInstance();
                    }
                    catch (Exception e) {
                        parser = null;
                        System.err.println("error: Unable to instantiate parser ("+parserName+")");
                    }
                    continue;
                }
                if (option.equals("e")) {
                    if (++i == argv.length) {
                        System.err.println("error: Missing argument to -e option.");
                    }
                    elementName = argv[i];
                    continue;
                }
                if (option.equals("a")) {
                    if (++i == argv.length) {
                        System.err.println("error: Missing argument to -a option.");
                    }
                    attributeName = argv[i];
                    continue;
                }
                if (option.equalsIgnoreCase("n")) {
                    namespaces = option.equals("n");
                    continue;
                }
                if (option.equalsIgnoreCase("v")) {
                    validation = option.equals("v");
                    continue;
                }
                if (option.equalsIgnoreCase("s")) {
                    schemaValidation = option.equals("s");
                    continue;
                }
                if (option.equalsIgnoreCase("f")) {
                    schemaFullChecking = option.equals("f");
                    continue;
                }
                if (option.equals("h")) {
                    printUsage();
                    continue;
                }
            }

            // use default parser?
            if (parser == null) {

                // create parser
                try {
                    parser = (ParserWrapper)Class.forName(DEFAULT_PARSER_NAME).newInstance();
                }
                catch (Exception e) {
                    System.err.println("error: Unable to instantiate parser ("+DEFAULT_PARSER_NAME+")");
                    continue;
                }
            }

            // set parser features
            try {
                parser.setFeature(NAMESPACES_FEATURE_ID, namespaces);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+NAMESPACES_FEATURE_ID+")");
            }
            try {
                parser.setFeature(VALIDATION_FEATURE_ID, validation);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+VALIDATION_FEATURE_ID+")");
            }
            try {
                parser.setFeature(SCHEMA_VALIDATION_FEATURE_ID, schemaValidation);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+SCHEMA_VALIDATION_FEATURE_ID+")");
            }
            try {
                parser.setFeature(SCHEMA_FULL_CHECKING_FEATURE_ID, schemaFullChecking);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+SCHEMA_FULL_CHECKING_FEATURE_ID+")");
            }

            // parse file
            try {
                Document document = parser.parse(arg);
                GetElementsByTagName.print(out, document, elementName, attributeName);
            }
            catch (SAXParseException e) {
                // ignore
            }
            catch (Exception e) {
                System.err.println("error: Parse error occurred - "+e.getMessage());
                if (e instanceof SAXException) {
                    e = ((SAXException)e).getException();
                }
                e.printStackTrace(System.err);
            }
        }

    } // main(String[])

    //
    // Private static methods
    //

    /** Prints the usage. */
    private static void printUsage() {

        System.err.println("usage: java dom.GetElementsByTagName (options) uri ...");
        System.err.println();

        System.err.println("options:");
        System.err.println("  -p name  Select parser by name.");
        System.err.println("  -e name  Specify element name for search.");
        System.err.println("  -a name  Specify attribute name for specified elements.");
        System.err.println("  -n | -N  Turn on/off namespace processing.");
        System.err.println("  -v | -V  Turn on/off validation.");
        System.err.println("  -s | -S  Turn on/off Schema validation support.");
        System.err.println("           NOTE: Not supported by all parsers.");
        System.err.println("  -f  | -F Turn on/off Schema full checking.");
        System.err.println("           NOTE: Requires use of -s and not supported by all parsers.");
        System.err.println("  -h       This help screen.");
        System.err.println();

        System.err.println("defaults:");
        System.err.println("  Parser:     "+DEFAULT_PARSER_NAME);
        System.err.println("  Element:    "+DEFAULT_ELEMENT_NAME);
        System.out.print("  Namespaces: ");
        System.err.println(DEFAULT_NAMESPACES ? "on" : "off");
        System.out.print("  Validation: ");
        System.err.println(DEFAULT_VALIDATION ? "on" : "off");
        System.out.print("  Schema:     ");
        System.err.println(DEFAULT_SCHEMA_VALIDATION ? "on" : "off");
        System.err.print("  Schema full checking:     ");
        System.err.println(DEFAULT_SCHEMA_FULL_CHECKING ? "on" : "off");

    } // printUsage()

} // class GetElementsByTagName