http://xmlgraphics.apache.org/fop/: Apache FOP (Formatting Objects Processor) is the world's first print formatter driven by XSL formatting objects (XSL-FO) and the world's first output independent formatter. It is a Java application that reads a formatting object (FO) tree and renders the resulting pages to a specified output. Output formats currently supported include PDF, PCL, PS, AFP, TIFF, PNG, SVG, XML (area tree representation), Print, AWT and TXT. The primary output target is PDF. (Apache Software Foundation) 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.
 */

/* $Id: XMLResourceBundle.java 1734671 2016-03-12 05:39:53Z gadams $ */

package org.apache.fop.util;

import java.io.IOException;
import java.io.InputStream;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.Stack;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.stream.StreamSource;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import org.apache.xmlgraphics.util.QName;


This class is a ResourceBundle that loads its contents from XML files instead of properties
files (like PropertiesResourceBundle).


The XML format for this resource bundle implementation is the following
(the same as Apache Cocoon's XMLResourceBundle):

<catalogue xml:lang="en">
  <message key="key1">Message <br/> Value 1</message>
  <message key="key2">Message <br/> Value 1</message>
  ...
</catalogue>



/**
 * This class is a ResourceBundle that loads its contents from XML files instead of properties
 * files (like PropertiesResourceBundle).
 * <p>
 * The XML format for this resource bundle implementation is the following
 * (the same as Apache Cocoon's XMLResourceBundle):
 * <pre>
 * &lt;catalogue xml:lang="en"&gt;
 *   &lt;message key="key1"&gt;Message &lt;br/&gt; Value 1&lt;/message&gt;
 *   &lt;message key="key2"&gt;Message &lt;br/&gt; Value 1&lt;/message&gt;
 *   ...
 * &lt;/catalogue&gt;
 * </pre>
 */
public class XMLResourceBundle extends ResourceBundle {

    //Note: Some code here has been copied and adapted from Apache Harmony!

    private Properties resources = new Properties();

    private Locale locale;

    private static SAXTransformerFactory tFactory
        = (SAXTransformerFactory)SAXTransformerFactory.newInstance();

    
Creates a resource bundle from an InputStream.

Params:
  • in – the stream to read from
Throws:
/**
     * Creates a resource bundle from an InputStream.
     * @param in the stream to read from
     * @throws IOException if an I/O error occurs
     */
    public XMLResourceBundle(InputStream in) throws IOException {
        try {
            Transformer transformer = tFactory.newTransformer();
            StreamSource src = new StreamSource(in);
            SAXResult res = new SAXResult(new CatalogueHandler());
            transformer.transform(src, res);
        } catch (TransformerException e) {
            throw new IOException("Error while parsing XML resource bundle: " + e.getMessage());
        }
    }

    
Gets a resource bundle using the specified base name, default locale, and class loader.

Params:
  • baseName – the base name of the resource bundle, a fully qualified class name
  • loader – the class loader from which to load the resource bundle
Throws:
See Also:
Returns:a resource bundle for the given base name and the default locale
/**
     * Gets a resource bundle using the specified base name, default locale, and class loader.
     * @param baseName the base name of the resource bundle, a fully qualified class name
     * @param loader the class loader from which to load the resource bundle
     * @return a resource bundle for the given base name and the default locale
     * @throws MissingResourceException if no resource bundle for the specified base name can be
     *                                          found
     * @see java.util.ResourceBundle#getBundle(String)
     */
    public static ResourceBundle getXMLBundle(String baseName, ClassLoader loader)
                throws MissingResourceException {
        return getXMLBundle(baseName, Locale.getDefault(), loader);
    }

    
Gets a resource bundle using the specified base name, locale, and class loader.

Params:
  • baseName – the base name of the resource bundle, a fully qualified class name
  • locale – the locale for which a resource bundle is desired
  • loader – the class loader from which to load the resource bundle
Throws:
See Also:
Returns:a resource bundle for the given base name and locale
/**
     * Gets a resource bundle using the specified base name, locale, and class loader.
     * @param baseName the base name of the resource bundle, a fully qualified class name
     * @param locale the locale for which a resource bundle is desired
     * @param loader the class loader from which to load the resource bundle
     * @return a resource bundle for the given base name and locale
     * @throws MissingResourceException if no resource bundle for the specified base name can be
     *                                          found
     * @see java.util.ResourceBundle#getBundle(String, Locale, ClassLoader)
     */
    public static ResourceBundle getXMLBundle(String baseName, Locale locale, ClassLoader loader)
                throws MissingResourceException {
        if (loader == null) {
            throw new NullPointerException("loader must not be null");
        }
        if (baseName == null) {
            throw new NullPointerException("baseName must not be null");
        }
        assert locale != null;
        ResourceBundle bundle;
        if (!locale.equals(Locale.getDefault())) {
            bundle = handleGetXMLBundle(baseName, "_" + locale, false, loader);
            if (bundle != null) {
                return bundle;
            }
        }
        bundle = handleGetXMLBundle(baseName, "_" + Locale.getDefault(), true, loader);
        if (bundle != null) {
            return bundle;
        }
        throw new MissingResourceException(
                baseName + " (" + locale + ")", baseName + '_' + locale, null);
    }

    static class MissingBundle extends ResourceBundle {
        public Enumeration getKeys() {
            return null;
        }

        public Object handleGetObject(String name) {
            return null;
        }
    }

    private static final ResourceBundle MISSING = new MissingBundle();
    private static final ResourceBundle MISSINGBASE = new MissingBundle();

    private static Map cache = new java.util.WeakHashMap();
    //<Object, Hashtable<String, ResourceBundle>>

    private static ResourceBundle handleGetXMLBundle(String base, String locale,
            boolean loadBase, final ClassLoader loader) {
        XMLResourceBundle bundle = null;
        String bundleName = base + locale;
        Object cacheKey = loader != null ? (Object) loader : (Object) "null";
        Hashtable loaderCache; //<String, ResourceBundle>
        synchronized (cache) {
            loaderCache = (Hashtable)cache.get(cacheKey);
            if (loaderCache == null) {
                loaderCache = new Hashtable();
                cache.put(cacheKey, loaderCache);
            }
        }
        ResourceBundle result = (ResourceBundle)loaderCache.get(bundleName);
        if (result != null) {
            if (result == MISSINGBASE) {
                return null;
            }
            if (result == MISSING) {
                if (!loadBase) {
                    return null;
                }
                String extension = strip(locale);
                if (extension == null) {
                    return null;
                }
                return handleGetXMLBundle(base, extension, loadBase, loader);
            }
            return result;
        }

        final String fileName = bundleName.replace('.', '/') + ".xml";
        InputStream stream = (InputStream)AccessController
                .doPrivileged(new PrivilegedAction() {
                    public Object run() {
                        return loader == null
                            ? ClassLoader.getSystemResourceAsStream(fileName)
                            : loader.getResourceAsStream(fileName);
                    }
                });
        if (stream != null) {
            try {
                try {
                    bundle = new XMLResourceBundle(stream);
                } finally {
                    stream.close();
                }
                bundle.setLocale(locale);
            } catch (IOException e) {
                throw new MissingResourceException(e.getMessage(), base, null);
            }
        }

        String extension = strip(locale);
        if (bundle != null) {
            if (extension != null) {
                ResourceBundle parent = handleGetXMLBundle(base, extension, true,
                        loader);
                if (parent != null) {
                    bundle.setParent(parent);
                }
            }
            loaderCache.put(bundleName, bundle);
            return bundle;
        }

        if (extension != null) {
            ResourceBundle fallback = handleGetXMLBundle(base, extension, loadBase, loader);
            if (fallback != null) {
                loaderCache.put(bundleName, fallback);
                return fallback;
            }
        }
        loaderCache.put(bundleName, loadBase ? MISSINGBASE : MISSING);
        return null;
    }

    private void setLocale(String name) {
        String language = "";
        String country = "";
        String variant = "";
        if (name.length() > 1) {
            int nextIndex = name.indexOf('_', 1);
            if (nextIndex == -1) {
                nextIndex = name.length();
            }
            language = name.substring(1, nextIndex);
            if (nextIndex + 1 < name.length()) {
                int index = nextIndex;
                nextIndex = name.indexOf('_', nextIndex + 1);
                if (nextIndex == -1) {
                    nextIndex = name.length();
                }
                country = name.substring(index + 1, nextIndex);
                if (nextIndex + 1 < name.length()) {
                    variant = name.substring(nextIndex + 1, name.length());
                }
            }
        }
        this.locale = new Locale(language, country, variant);
    }

    private static String strip(String name) {
        int index = name.lastIndexOf('_');
        if (index != -1) {
            return name.substring(0, index);
        }
        return null;
    }

    private Enumeration getLocalKeys() {
        return (Enumeration)resources.propertyNames();
    }

    
{@inheritDoc} 
/** {@inheritDoc} */
    public Locale getLocale() {
        return this.locale;
    }

    
{@inheritDoc} 
/** {@inheritDoc} */
    public Enumeration getKeys() {
        if (parent == null) {
            return getLocalKeys();
        }
        return new Enumeration() {
            private Enumeration local = getLocalKeys();
            private Enumeration pEnum = parent.getKeys();

            private Object nextElement;

            private boolean findNext() {
                if (nextElement != null) {
                    return true;
                }
                while (pEnum.hasMoreElements()) {
                    Object next = pEnum.nextElement();
                    if (!resources.containsKey(next)) {
                        nextElement = next;
                        return true;
                    }
                }
                return false;
            }

            public boolean hasMoreElements() {
                if (local.hasMoreElements()) {
                    return true;
                }
                return findNext();
            }

            public Object nextElement() {
                if (local.hasMoreElements()) {
                    return local.nextElement();
                }
                if (findNext()) {
                    Object result = nextElement;
                    nextElement = null;
                    return result;
                }
                // Cause an exception
                return pEnum.nextElement();
            }
        };
    }

    
{@inheritDoc} 
/** {@inheritDoc} */
    protected Object handleGetObject(String key) {
        if (key == null) {
            throw new NullPointerException("key must not be null");
        }
        return resources.get(key);
    }

    
{@inheritDoc} 
/** {@inheritDoc} */
    public String toString() {
        return "XMLResourceBundle: " + getLocale();
    }

    private class CatalogueHandler extends DefaultHandler {

        private static final String CATALOGUE = "catalogue";
        private static final String MESSAGE = "message";

        private StringBuffer valueBuffer = new StringBuffer();
        private Stack elementStack = new Stack();
        private String currentKey;

        private boolean isOwnNamespace(String uri) {
            return ("".equals(uri));
        }

        private QName getParentElementName() {
            return (QName)elementStack.peek();
        }

        
{@inheritDoc} 
/** {@inheritDoc} */
        public void startElement(String uri, String localName, String qName,
                Attributes atts) throws SAXException {
            super.startElement(uri, localName, qName, atts);
            QName elementName = new QName(uri, qName);
            if (isOwnNamespace(uri)) {
                if (CATALOGUE.equals(localName)) {
                    //nop
                } else if (MESSAGE.equals(localName)) {
                    if (!CATALOGUE.equals(getParentElementName().getLocalName())) {
                        throw new SAXException(MESSAGE + " must be a child of " + CATALOGUE);
                    }
                    this.currentKey = atts.getValue("key");
                } else {
                    throw new SAXException("Invalid element name: " + elementName);
                }
            } else {
                //ignore
            }
            this.valueBuffer.setLength(0);
            elementStack.push(elementName);
        }

        
{@inheritDoc} 
/** {@inheritDoc} */
        public void endElement(String uri, String localName, String qName) throws SAXException {
            super.endElement(uri, localName, qName);
            elementStack.pop();
            if (isOwnNamespace(uri)) {
                if (CATALOGUE.equals(localName)) {
                    //nop
                } else if (MESSAGE.equals(localName)) {
                    if (this.currentKey == null) {
                        throw new SAXException(
                                "current key is null (attribute 'key' might be mistyped)");
                    }
                    resources.put(this.currentKey, this.valueBuffer.toString());
                    this.currentKey = null;
                }
            } else {
                //ignore
            }
            this.valueBuffer.setLength(0);
        }

        
{@inheritDoc} 
/** {@inheritDoc} */
        public void characters(char[] ch, int start, int length) throws SAXException {
            super.characters(ch, start, length);
            valueBuffer.append(ch, start, length);
        }

    }

}