Home | History | Annotate | Download | only in util 
      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 java.io.IOException;
     20 import java.io.InputStream;
     21 import java.io.Reader;
     22 import java.io.StringReader;
     23 import java.io.UnsupportedEncodingException;
     24 import org.apache.harmony.xml.ExpatReader;
     25 import org.kxml2.io.KXmlParser;
     26 import org.xml.sax.ContentHandler;
     27 import org.xml.sax.InputSource;
     28 import org.xml.sax.SAXException;
     29 import org.xml.sax.XMLReader;
     30 import org.xmlpull.v1.XmlPullParser;
     31 import org.xmlpull.v1.XmlPullParserException;
     32 import org.xmlpull.v1.XmlPullParserFactory;
     33 import org.xmlpull.v1.XmlSerializer;
     34 
     35 /**
     36  * XML utility methods.
     37  */
     38 public class Xml {
     39     /** @hide */ public 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 = new ExpatReader();
     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 = new ExpatReader();
     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 = new ExpatReader();
     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             KXmlParser parser = new KXmlParser();
     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         try {
    106             return XmlSerializerFactory.instance.newSerializer();
    107         } catch (XmlPullParserException e) {
    108             throw new AssertionError(e);
    109         }
    110     }
    111 
    112     /** Factory for xml serializers. Initialized on demand. */
    113     static class XmlSerializerFactory {
    114         static final String TYPE
    115                 = "org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer";
    116         static final XmlPullParserFactory instance;
    117         static {
    118             try {
    119                 instance = XmlPullParserFactory.newInstance(TYPE, null);
    120             } catch (XmlPullParserException e) {
    121                 throw new AssertionError(e);
    122             }
    123         }
    124     }
    125 
    126     /**
    127      * Supported character encodings.
    128      */
    129     public enum Encoding {
    130 
    131         US_ASCII("US-ASCII"),
    132         UTF_8("UTF-8"),
    133         UTF_16("UTF-16"),
    134         ISO_8859_1("ISO-8859-1");
    135 
    136         final String expatName;
    137 
    138         Encoding(String expatName) {
    139             this.expatName = expatName;
    140         }
    141     }
    142 
    143     /**
    144      * Finds an encoding by name. Returns UTF-8 if you pass {@code null}.
    145      */
    146     public static Encoding findEncodingByName(String encodingName)
    147             throws UnsupportedEncodingException {
    148         if (encodingName == null) {
    149             return Encoding.UTF_8;
    150         }
    151 
    152         for (Encoding encoding : Encoding.values()) {
    153             if (encoding.expatName.equalsIgnoreCase(encodingName))
    154                 return encoding;
    155         }
    156         throw new UnsupportedEncodingException(encodingName);
    157     }
    158 
    159     /**
    160      * Return an AttributeSet interface for use with the given XmlPullParser.
    161      * If the given parser itself implements AttributeSet, that implementation
    162      * is simply returned.  Otherwise a wrapper class is
    163      * instantiated on top of the XmlPullParser, as a proxy for retrieving its
    164      * attributes, and returned to you.
    165      *
    166      * @param parser The existing parser for which you would like an
    167      *               AttributeSet.
    168      *
    169      * @return An AttributeSet you can use to retrieve the
    170      *         attribute values at each of the tags as the parser moves
    171      *         through its XML document.
    172      *
    173      * @see AttributeSet
    174      */
    175     public static AttributeSet asAttributeSet(XmlPullParser parser) {
    176         return (parser instanceof AttributeSet)
    177                 ? (AttributeSet) parser
    178                 : new XmlPullAttributes(parser);
    179     }
    180 }
    181