Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2009 Mike Cumings |
| 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 com.kenai.jbosh; |
| 18 | |
| 19 | import java.io.IOException; |
| 20 | import java.io.StringReader; |
| 21 | import java.lang.ref.SoftReference; |
| 22 | import java.util.logging.Level; |
| 23 | import java.util.logging.Logger; |
| 24 | import javax.xml.XMLConstants; |
| 25 | import org.xmlpull.v1.XmlPullParser; |
| 26 | import org.xmlpull.v1.XmlPullParserException; |
| 27 | import org.xmlpull.v1.XmlPullParserFactory; |
| 28 | |
| 29 | /** |
| 30 | * Implementation of the BodyParser interface which uses the XmlPullParser |
| 31 | * API. When available, this API provides an order of magnitude performance |
| 32 | * improvement over the default SAX parser implementation. |
| 33 | */ |
| 34 | final class BodyParserXmlPull implements BodyParser { |
| 35 | |
| 36 | /** |
| 37 | * Logger. |
| 38 | */ |
| 39 | private static final Logger LOG = |
| 40 | Logger.getLogger(BodyParserXmlPull.class.getName()); |
| 41 | |
| 42 | /** |
| 43 | * Thread local to contain a XmlPullParser instance for each thread that |
| 44 | * attempts to use one. This allows us to gain an order of magnitude of |
| 45 | * performance as a result of not constructing parsers for each |
| 46 | * invocation while retaining thread safety. |
| 47 | */ |
| 48 | private static final ThreadLocal<SoftReference<XmlPullParser>> XPP_PARSER = |
| 49 | new ThreadLocal<SoftReference<XmlPullParser>>() { |
| 50 | @Override protected SoftReference<XmlPullParser> initialValue() { |
| 51 | return new SoftReference<XmlPullParser>(null); |
| 52 | } |
| 53 | }; |
| 54 | |
| 55 | /////////////////////////////////////////////////////////////////////////// |
| 56 | // BodyParser interface methods: |
| 57 | |
| 58 | /** |
| 59 | * {@inheritDoc} |
| 60 | */ |
| 61 | public BodyParserResults parse(final String xml) throws BOSHException { |
| 62 | BodyParserResults result = new BodyParserResults(); |
| 63 | Exception thrown; |
| 64 | try { |
| 65 | XmlPullParser xpp = getXmlPullParser(); |
| 66 | |
| 67 | xpp.setInput(new StringReader(xml)); |
| 68 | int eventType = xpp.getEventType(); |
| 69 | while (eventType != XmlPullParser.END_DOCUMENT) { |
| 70 | if (eventType == XmlPullParser.START_TAG) { |
| 71 | if (LOG.isLoggable(Level.FINEST)) { |
| 72 | LOG.finest("Start tag: " + xpp.getName()); |
| 73 | } |
| 74 | } else { |
| 75 | eventType = xpp.next(); |
| 76 | continue; |
| 77 | } |
| 78 | |
| 79 | String prefix = xpp.getPrefix(); |
| 80 | if (prefix == null) { |
| 81 | prefix = XMLConstants.DEFAULT_NS_PREFIX; |
| 82 | } |
| 83 | String uri = xpp.getNamespace(); |
| 84 | String localName = xpp.getName(); |
| 85 | QName name = new QName(uri, localName, prefix); |
| 86 | if (LOG.isLoggable(Level.FINEST)) { |
| 87 | LOG.finest("Start element: "); |
| 88 | LOG.finest(" prefix: " + prefix); |
| 89 | LOG.finest(" URI: " + uri); |
| 90 | LOG.finest(" local: " + localName); |
| 91 | } |
| 92 | |
| 93 | BodyQName bodyName = AbstractBody.getBodyQName(); |
| 94 | if (!bodyName.equalsQName(name)) { |
| 95 | throw(new IllegalStateException( |
| 96 | "Root element was not '" + bodyName.getLocalPart() |
| 97 | + "' in the '" + bodyName.getNamespaceURI() |
| 98 | + "' namespace. (Was '" + localName |
| 99 | + "' in '" + uri + "')")); |
| 100 | } |
| 101 | |
| 102 | for (int idx=0; idx < xpp.getAttributeCount(); idx++) { |
| 103 | String attrURI = xpp.getAttributeNamespace(idx); |
| 104 | if (attrURI.length() == 0) { |
| 105 | attrURI = xpp.getNamespace(null); |
| 106 | } |
| 107 | String attrPrefix = xpp.getAttributePrefix(idx); |
| 108 | if (attrPrefix == null) { |
| 109 | attrPrefix = XMLConstants.DEFAULT_NS_PREFIX; |
| 110 | } |
| 111 | String attrLN = xpp.getAttributeName(idx); |
| 112 | String attrVal = xpp.getAttributeValue(idx); |
| 113 | BodyQName aqn = BodyQName.createWithPrefix( |
| 114 | attrURI, attrLN, attrPrefix); |
| 115 | if (LOG.isLoggable(Level.FINEST)) { |
| 116 | LOG.finest(" Attribute: {" + attrURI + "}" |
| 117 | + attrLN + " = '" + attrVal + "'"); |
| 118 | } |
| 119 | result.addBodyAttributeValue(aqn, attrVal); |
| 120 | } |
| 121 | break; |
| 122 | } |
| 123 | return result; |
| 124 | } catch (RuntimeException rtx) { |
| 125 | thrown = rtx; |
| 126 | } catch (XmlPullParserException xmlppx) { |
| 127 | thrown = xmlppx; |
| 128 | } catch (IOException iox) { |
| 129 | thrown = iox; |
| 130 | } |
| 131 | throw(new BOSHException("Could not parse body:\n" + xml, thrown)); |
| 132 | } |
| 133 | |
| 134 | /////////////////////////////////////////////////////////////////////////// |
| 135 | // Private methods: |
| 136 | |
| 137 | /** |
| 138 | * Gets a XmlPullParser for use in parsing incoming messages. |
| 139 | * |
| 140 | * @return parser instance |
| 141 | */ |
| 142 | private static XmlPullParser getXmlPullParser() { |
| 143 | SoftReference<XmlPullParser> ref = XPP_PARSER.get(); |
| 144 | XmlPullParser result = ref.get(); |
| 145 | if (result == null) { |
| 146 | Exception thrown; |
| 147 | try { |
| 148 | XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); |
| 149 | factory.setNamespaceAware(true); |
| 150 | factory.setValidating(false); |
| 151 | result = factory.newPullParser(); |
| 152 | ref = new SoftReference<XmlPullParser>(result); |
| 153 | XPP_PARSER.set(ref); |
| 154 | return result; |
| 155 | } catch (Exception ex) { |
| 156 | thrown = ex; |
| 157 | } |
| 158 | throw(new IllegalStateException( |
| 159 | "Could not create XmlPull parser", thrown)); |
| 160 | } else { |
| 161 | return result; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | } |