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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.util;
     18 
     19 import libcore.util.XmlObjectFactory;
     20 
     21 import org.xml.sax.ContentHandler;
     22 import org.xml.sax.InputSource;
     23 import org.xml.sax.SAXException;
     24 import org.xml.sax.XMLReader;
     25 import org.xmlpull.v1.XmlPullParser;
     26 import org.xmlpull.v1.XmlPullParserException;
     27 import org.xmlpull.v1.XmlSerializer;
     28 
     29 import java.io.IOException;
     30 import java.io.InputStream;
     31 import java.io.Reader;
     32 import java.io.StringReader;
     33 import java.io.UnsupportedEncodingException;
     34 
     35 /**
     36  * XML utility methods.
     37  */
     38 public class Xml {
     39     private Xml() {}
     40 
     41     /**
     42      * {@link org.xmlpull.v1.XmlPullParser} "relaxed" feature name.
     43      *
     44      * @see <a href="http://xmlpull.org/v1/doc/features.html#relaxed">
     45      *  specification</a>
     46      */
     47     public static String FEATURE_RELAXED = "http://xmlpull.org/v1/doc/features.html#relaxed";
     48 
     49     /**
     50      * Parses the given xml string and fires events on the given SAX handler.
     51      */
     52     public static void parse(String xml, ContentHandler contentHandler)
     53             throws SAXException {
     54         try {
     55             XMLReader reader = XmlObjectFactory.newXMLReader();
     56             reader.setContentHandler(contentHandler);
     57             reader.parse(new InputSource(new StringReader(xml)));
     58         } catch (IOException e) {
     59             throw new AssertionError(e);
     60         }
     61     }
     62 
     63     /**
     64      * Parses xml from the given reader and fires events on the given SAX
     65      * handler.
     66      */
     67     public static void parse(Reader in, ContentHandler contentHandler)
     68             throws IOException, SAXException {
     69         XMLReader reader = XmlObjectFactory.newXMLReader();
     70         reader.setContentHandler(contentHandler);
     71         reader.parse(new InputSource(in));
     72     }
     73 
     74     /**
     75      * Parses xml from the given input stream and fires events on the given SAX
     76      * handler.
     77      */
     78     public static void parse(InputStream in, Encoding encoding,
     79             ContentHandler contentHandler) throws IOException, SAXException {
     80         XMLReader reader = XmlObjectFactory.newXMLReader();
     81         reader.setContentHandler(contentHandler);
     82         InputSource source = new InputSource(in);
     83         source.setEncoding(encoding.expatName);
     84         reader.parse(source);
     85     }
     86 
     87     /**
     88      * Returns a new pull parser with namespace support.
     89      */
     90     public static XmlPullParser newPullParser() {
     91         try {
     92             XmlPullParser parser = XmlObjectFactory.newXmlPullParser();
     93             parser.setFeature(XmlPullParser.FEATURE_PROCESS_DOCDECL, true);
     94             parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
     95             return parser;
     96         } catch (XmlPullParserException e) {
     97             throw new AssertionError();
     98         }
     99     }
    100 
    101     /**
    102      * Creates a new xml serializer.
    103      */
    104     public static XmlSerializer newSerializer() {
    105         return XmlObjectFactory.newXmlSerializer();
    106     }
    107 
    108     /**
    109      * Supported character encodings.
    110      */
    111     public enum Encoding {
    112 
    113         US_ASCII("US-ASCII"),
    114         UTF_8("UTF-8"),
    115         UTF_16("UTF-16"),
    116         ISO_8859_1("ISO-8859-1");
    117 
    118         final String expatName;
    119 
    120         Encoding(String expatName) {
    121             this.expatName = expatName;
    122         }
    123     }
    124 
    125     /**
    126      * Finds an encoding by name. Returns UTF-8 if you pass {@code null}.
    127      */
    128     public static Encoding findEncodingByName(String encodingName)
    129             throws UnsupportedEncodingException {
    130         if (encodingName == null) {
    131             return Encoding.UTF_8;
    132         }
    133 
    134         for (Encoding encoding : Encoding.values()) {
    135             if (encoding.expatName.equalsIgnoreCase(encodingName))
    136                 return encoding;
    137         }
    138         throw new UnsupportedEncodingException(encodingName);
    139     }
    140 
    141     /**
    142      * Return an AttributeSet interface for use with the given XmlPullParser.
    143      * If the given parser itself implements AttributeSet, that implementation
    144      * is simply returned.  Otherwise a wrapper class is
    145      * instantiated on top of the XmlPullParser, as a proxy for retrieving its
    146      * attributes, and returned to you.
    147      *
    148      * @param parser The existing parser for which you would like an
    149      *               AttributeSet.
    150      *
    151      * @return An AttributeSet you can use to retrieve the
    152      *         attribute values at each of the tags as the parser moves
    153      *         through its XML document.
    154      *
    155      * @see AttributeSet
    156      */
    157     public static AttributeSet asAttributeSet(XmlPullParser parser) {
    158         return (parser instanceof AttributeSet)
    159                 ? (AttributeSet) parser
    160                 : new XmlPullAttributes(parser);
    161     }
    162 }
    163