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// CatalogReader.java - Read OASIS Catalog files
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// Written by Norman Walsh, nwalsh@arbortext.com
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// NO WARRANTY! This class is in the public domain.
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package com.arbortext.catalog;
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import java.lang.Integer;
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import java.io.DataInputStream;
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import java.io.IOException;
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import java.io.FileNotFoundException;
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import java.net.URL;
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import java.net.MalformedURLException;
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import com.arbortext.catalog.CatalogEntry;
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import com.arbortext.catalog.InvalidCatalogEntryTypeException;
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import com.arbortext.catalog.InvalidCatalogEntryException;
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/**
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* <p>Parses OASIS Open Catalog files.</p>
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*
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* <blockquote>
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* <em>This module, both source code and documentation, is in the
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* Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
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* </blockquote>
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*
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* <p>This class reads OASIS Open Catalog files, returning a stream
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* of tokens.</p>
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*
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* <p>This code interrogates the following non-standard system properties:</p>
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*
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* <dl>
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* <dt><b>xml.catalog.debug</b></dt>
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* <dd><p>Sets the debug level. A value of 0 is assumed if the
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* property is not set or is not a number.</p></dd>
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* </dl>
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*
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* @see Catalog
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*
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* @author Arbortext, Inc.
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* @author Norman Walsh
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* <a href="mailto:nwalsh@arbortext.com">nwalsh@arbortext.com</a>
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* @version 1.0
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*/
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public class CatalogReader {
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// These are class variables so that several methods can access them
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/** The filename (URL) of the catalog being read */
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private String catfilename = null;
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/** The input stream used to read the catalog */
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private DataInputStream catfile = null;
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/**
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* Lookahead stack. Reading a catalog sometimes requires up to
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* two characters of lookahead.
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*/
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private int[] stack = new int[3];
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/** The current position on the lookahead stack */
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private int top = -1;
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/**
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* <p>The debug level</p>
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*
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* <p>In general, higher numbers produce more information:</p>
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* <ul>
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* <li>0, no messages
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* <li>1, minimal messages (high-level status)
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* <li>2, detailed messages
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* </ul>
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*/
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public int debug = 0;
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/**
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* <p>Construct a CatalogReader object.</p>
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*/
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public CatalogReader() {
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String property = System.getProperty("xml.catalog.debug");
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if (property != null) {
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try {
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debug = Integer.parseInt(property);
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} catch (NumberFormatException e) {
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debug = 0;
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}
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}
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}
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/**
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* <p>Start parsing an OASIS Open Catalog file. The file is
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* actually read and parsed
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* as needed by <code>nextEntry</code>.</p>
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*
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* @param fileUrl The URL or filename of the catalog file to process
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*
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* @throws MalformedURLException Improper fileUrl
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* @throws IOException Error reading catalog file
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*/
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public void parseCatalog(String fileUrl)
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throws MalformedURLException, IOException {
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catfilename = fileUrl;
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URL catalog;
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try {
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catalog = new URL(fileUrl);
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} catch (MalformedURLException e) {
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catalog = new URL("file:///" + fileUrl);
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}
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try {
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catfile = new DataInputStream(catalog.openStream());
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} catch (FileNotFoundException e) {
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debug(1, "Failed to load catalog, file not found", catalog.toString());
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}
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}
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/**
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* <p>The destructor.</p>
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*
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* <p>Makes sure the catalog file is closed.</p>
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*/
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protected void finalize() throws IOException {
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if (catfile != null) {
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catfile.close();
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}
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catfile = null;
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}
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/**
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* <p>Get the next entry from the file</p>
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*
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* @throws IOException Error reading catalog file
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* @return A CatalogEntry object for the next entry in the catalog
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*/
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public CatalogEntry nextEntry() throws IOException {
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if (catfile == null) {
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return null;
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}
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boolean confused = false;
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while (true) {
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String token = nextToken();
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if (token == null) {
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catfile.close();
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catfile = null;
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return null;
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}
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if (token.equalsIgnoreCase("BASE")
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|| token.equalsIgnoreCase("CATALOG")
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|| token.equalsIgnoreCase("DOCUMENT")
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|| token.equalsIgnoreCase("OVERRIDE")
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|| token.equalsIgnoreCase("SGMLDECL")) {
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String spec = nextToken();
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confused = false;
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try {
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if (token.equalsIgnoreCase("BASE")) {
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return new CatalogEntry(CatalogEntry.BASE, spec);
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}
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if (token.equalsIgnoreCase("CATALOG")) {
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return new CatalogEntry(CatalogEntry.CATALOG, spec);
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}
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if (token.equalsIgnoreCase("DOCUMENT")) {
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return new CatalogEntry(CatalogEntry.DOCUMENT, spec);
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}
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if (token.equalsIgnoreCase("OVERRIDE")) {
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return new CatalogEntry(CatalogEntry.OVERRIDE, spec);
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}
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if (token.equalsIgnoreCase("SGMLDECL")) {
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return new CatalogEntry(CatalogEntry.SGMLDECL, spec);
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}
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} catch (InvalidCatalogEntryTypeException icete) {
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debug(1, "Invalid catalog entry type", token);
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confused = true;
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} catch (InvalidCatalogEntryException icete) {
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debug(1, "Invalid catalog entry", token, spec);
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confused = true;
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}
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}
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if (token.equalsIgnoreCase("DELEGATE")
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|| token.equalsIgnoreCase("DOCTYPE")
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|| token.equalsIgnoreCase("DTDDECL")
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|| token.equalsIgnoreCase("ENTITY")
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|| token.equalsIgnoreCase("LINKTYPE")
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|| token.equalsIgnoreCase("NOTATION")
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|| token.equalsIgnoreCase("PUBLIC")
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|| token.equalsIgnoreCase("SYSTEM")) {
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String spec1 = nextToken();
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String spec2 = nextToken();
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confused = false;
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try {
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if (token.equalsIgnoreCase("DELEGATE")) {
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return new CatalogEntry(CatalogEntry.DELEGATE,
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normalize(spec1), spec2);
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}
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if (token.equalsIgnoreCase("DOCTYPE")) {
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return new CatalogEntry(CatalogEntry.DOCTYPE,
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spec1, spec2);
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}
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if (token.equalsIgnoreCase("DTDDECL")) {
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return new CatalogEntry(CatalogEntry.DTDDECL,
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normalize(spec1), spec2);
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}
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if (token.equalsIgnoreCase("ENTITY")) {
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return new CatalogEntry(CatalogEntry.ENTITY,
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spec1, spec2);
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}
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if (token.equalsIgnoreCase("LINKTYPE")) {
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return new CatalogEntry(CatalogEntry.LINKTYPE,
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spec1, spec2);
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}
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if (token.equalsIgnoreCase("NOTATION")) {
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return new CatalogEntry(CatalogEntry.NOTATION,
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spec1, spec2);
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}
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if (token.equalsIgnoreCase("PUBLIC")) {
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return new CatalogEntry(CatalogEntry.PUBLIC,
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normalize(spec1), spec2);
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}
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if (token.equalsIgnoreCase("SYSTEM")) {
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return new CatalogEntry(CatalogEntry.SYSTEM,
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spec1, spec2);
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}
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} catch (InvalidCatalogEntryTypeException icete) {
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debug(1, "Invalid catalog entry type", token);
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confused = true;
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} catch (InvalidCatalogEntryException icete) {
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debug(1, "Invalid catalog entry", token, spec1, spec2);
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confused = true;
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}
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}
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if (!confused) {
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if (debug > 1) {
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System.out.println("Unrecognized token parsing catalog: '"
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+ catfilename
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+ "': "
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+ token);
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System.out.println("\tSkipping to next recognized token.");
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}
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confused = true;
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}
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}
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}
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// -----------------------------------------------------------------
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/**
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* <p>Normalize a public identifier.</p>
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*
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* <p>Public identifiers must be normalized according to the following
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* rules before comparisons between them can be made:</p>
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*
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* <ul>
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* <li>Whitespace characters are normalized to spaces (e.g., line feeds,
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* tabs, etc. become spaces).</li>
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* <li>Leading and trailing whitespace is removed.</li>
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* <li>Multiple internal whitespaces are normalized to a single
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* space.</li>
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* </ul>
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*
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* <p>This method is declared static so that other classes
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* can use it directly.</p>
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*
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* @param publicId The unnormalized public identifier.
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*
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* @return The normalized identifier.
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*/
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public static String normalize(String publicId) {
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String normal = publicId.replace('\t', ' ');
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normal = normal.replace('\r', ' ');
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normal = normal.replace('\n', ' ');
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normal = normal.trim();
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int pos;
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while ((pos = normal.indexOf(" ")) >= 0) {
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normal = normal.substring(0, pos) + normal.substring(pos+1);
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}
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return normal;
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}
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// -----------------------------------------------------------------
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/**
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* <p>Return the next token in the catalog file.</p>
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*
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* @return The Catalog file token from the input stream.
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* @throws IOException If an error occurs reading from the stream.
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*/
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private String nextToken() throws IOException {
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String token = "";
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int ch, nextch;
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// Skip over leading whitespace and comments
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while (true) {
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// skip leading whitespace
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ch = catfile.read();
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while (ch <= ' ') { // all ctrls are whitespace
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ch = catfile.read();
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if (ch < 0) {
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return null;
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}
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}
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// now 'ch' is the current char from the file
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nextch = catfile.read();
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if (nextch < 0) {
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return null;
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}
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if (ch == '-' && nextch == '-') {
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// we've found a comment, skip it...
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ch = ' ';
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nextch = nextChar();
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while (ch != '-' || nextch != '-') {
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ch = nextch;
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nextch = nextChar();
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}
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// Ok, we've found the end of the comment,
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// loop back to the top and start again...
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} else {
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stack[++top] = nextch;
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stack[++top] = ch;
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break;
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}
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}
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ch = nextChar();
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if (ch == '"' || ch == '\'') {
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int quote = ch;
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while ((ch = nextChar()) != quote) {
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char[] chararr = new char[1];
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chararr[0] = (char) ch;
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String s = new String(chararr);
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token = token.concat(s);
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}
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return token;
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} else {
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// return the next whitespace or comment delimited
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// string
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while (ch > ' ') {
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nextch = nextChar();
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if (ch == '-' && nextch == '-') {
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stack[++top] = ch;
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stack[++top] = nextch;
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return token;
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} else {
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char[] chararr = new char[1];
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chararr[0] = (char) ch;
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String s = new String(chararr);
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token = token.concat(s);
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ch = nextch;
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}
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}
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return token;
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}
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}
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/**
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* <p>Return the next logical character from the input stream.</p>
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*
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* @return The next (logical) character from the input stream. The
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* character may be buffered from a previous lookahead.
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*
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* @throws IOException If an error occurs reading from the stream.
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*/
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private int nextChar() throws IOException {
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if (top < 0) {
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return catfile.read();
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} else {
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return stack[top--];
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}
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}
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/**
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* <p>Print debug message (if the debug level is high enough).</p>
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*
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* @param level The debug level of this message. This message
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* will only be
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* displayed if the current debug level is at least equal to this
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* value.
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* @param message The text of the message.
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* @param token The catalog file token being processed.
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*/
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private void debug(int level, String message, String token) {
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if (debug >= level) {
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System.out.println(message + ": " + token);
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}
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}
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/**
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* <p>Print debug message (if the debug level is high enough).</p>
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*
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* @param level The debug level of this message. This message
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* will only be
|
401
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* displayed if the current debug level is at least equal to this
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* value.
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* @param message The text of the message.
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* @param token The catalog file token being processed.
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* @param spec The argument to the token.
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*/
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private void debug(int level, String message, String token, String spec) {
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if (debug >= level) {
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System.out.println(message + ": " + token + " " + spec);
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}
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}
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412
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413
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/**
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* <p>Print debug message (if the debug level is high enough).</p>
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*
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* @param level The debug level of this message. This message
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* will only be
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* displayed if the current debug level is at least equal to this
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* value.
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* @param message The text of the message.
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* @param token The catalog file token being processed.
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* @param spec1 The first argument to the token.
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* @param spec2 The second argument to the token.
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*/
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425
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private void debug(int level, String message,
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String token, String spec1, String spec2) {
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if (debug >= level) {
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System.out.println(message + ": " + token + " " + spec1);
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System.out.println("\t" + spec2);
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}
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}
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}
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