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Diffstat (limited to 'src/share/classes/com/sun/org/apache/xml/internal/serializer/AttributesImplSerializer.java')
| -rw-r--r-- | src/share/classes/com/sun/org/apache/xml/internal/serializer/AttributesImplSerializer.java | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/src/share/classes/com/sun/org/apache/xml/internal/serializer/AttributesImplSerializer.java b/src/share/classes/com/sun/org/apache/xml/internal/serializer/AttributesImplSerializer.java new file mode 100644 index 0000000..d6bdc91 --- /dev/null +++ b/src/share/classes/com/sun/org/apache/xml/internal/serializer/AttributesImplSerializer.java @@ -0,0 +1,239 @@ +/* + * reserved comment block + * DO NOT REMOVE OR ALTER! + */ +/* + * Copyright 2003-2004 The Apache Software Foundation. + * + * Licensed 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: AttributesImplSerializer.java,v 1.2.4.1 2005/09/15 08:15:14 suresh_emailid Exp $ + */ + +package com.sun.org.apache.xml.internal.serializer; + +import java.util.Hashtable; + +import org.xml.sax.Attributes; +import org.xml.sax.helpers.AttributesImpl; + +/** + * This class extends org.xml.sax.helpers.AttributesImpl which implements org. + * xml.sax.Attributes. But for optimization this class adds a Hashtable for + * faster lookup of an index by qName, which is commonly done in the stream + * serializer. + * + * @see org.xml.sax.Attributes + * + * @xsl.usage internal + */ +public final class AttributesImplSerializer extends AttributesImpl +{ + /** + * Hash table of qName/index values to quickly lookup the index + * of an attributes qName. qNames are in uppercase in the hash table + * to make the search case insensitive. + * + * The keys to the hashtable to find the index are either + * "prefix:localName" or "{uri}localName". + */ + private final Hashtable m_indexFromQName = new Hashtable(); + + private final StringBuffer m_buff = new StringBuffer(); + + /** + * This is the number of attributes before switching to the hash table, + * and can be tuned, but 12 seems good for now - Brian M. + */ + private static final int MAX = 12; + + /** + * One less than the number of attributes before switching to + * the Hashtable. + */ + private static final int MAXMinus1 = MAX - 1; + + /** + * This method gets the index of an attribute given its qName. + * @param qname the qualified name of the attribute, e.g. "prefix1:locName1" + * @return the integer index of the attribute. + * @see org.xml.sax.Attributes#getIndex(String) + */ + public final int getIndex(String qname) + { + int index; + + if (super.getLength() < MAX) + { + // if we haven't got too many attributes let the + // super class look it up + index = super.getIndex(qname); + return index; + } + // we have too many attributes and the super class is slow + // so find it quickly using our Hashtable. + Integer i = (Integer)m_indexFromQName.get(qname); + if (i == null) + index = -1; + else + index = i.intValue(); + return index; + } + /** + * This method adds the attribute, but also records its qName/index pair in + * the hashtable for fast lookup by getIndex(qName). + * @param uri the URI of the attribute + * @param local the local name of the attribute + * @param qname the qualified name of the attribute + * @param type the type of the attribute + * @param val the value of the attribute + * + * @see org.xml.sax.helpers.AttributesImpl#addAttribute(String, String, String, String, String) + * @see #getIndex(String) + */ + public final void addAttribute( + String uri, + String local, + String qname, + String type, + String val) + { + int index = super.getLength(); + super.addAttribute(uri, local, qname, type, val); + // (index + 1) is now the number of attributes + // so either compare (index+1) to MAX, or compare index to (MAX-1) + + if (index < MAXMinus1) + { + return; + } + else if (index == MAXMinus1) + { + switchOverToHash(MAX); + } + else + { + /* add the key with the format of "prefix:localName" */ + /* we have just added the attibute, its index is the old length */ + Integer i = new Integer(index); + m_indexFromQName.put(qname, i); + + /* now add with key of the format "{uri}localName" */ + m_buff.setLength(0); + m_buff.append('{').append(uri).append('}').append(local); + String key = m_buff.toString(); + m_indexFromQName.put(key, i); + } + return; + } + + /** + * We are switching over to having a hash table for quick look + * up of attributes, but up until now we haven't kept any + * information in the Hashtable, so we now update the Hashtable. + * Future additional attributes will update the Hashtable as + * they are added. + * @param numAtts + */ + private void switchOverToHash(int numAtts) + { + for (int index = 0; index < numAtts; index++) + { + String qName = super.getQName(index); + Integer i = new Integer(index); + m_indexFromQName.put(qName, i); + + // Add quick look-up to find with uri/local name pair + String uri = super.getURI(index); + String local = super.getLocalName(index); + m_buff.setLength(0); + m_buff.append('{').append(uri).append('}').append(local); + String key = m_buff.toString(); + m_indexFromQName.put(key, i); + } + } + + /** + * This method clears the accumulated attributes. + * + * @see org.xml.sax.helpers.AttributesImpl#clear() + */ + public final void clear() + { + + int len = super.getLength(); + super.clear(); + if (MAX <= len) + { + // if we have had enough attributes and are + // using the Hashtable, then clear the Hashtable too. + m_indexFromQName.clear(); + } + + } + + /** + * This method sets the attributes, previous attributes are cleared, + * it also keeps the hashtable up to date for quick lookup via + * getIndex(qName). + * @param atts the attributes to copy into these attributes. + * @see org.xml.sax.helpers.AttributesImpl#setAttributes(Attributes) + * @see #getIndex(String) + */ + public final void setAttributes(Attributes atts) + { + + super.setAttributes(atts); + + // we've let the super class add the attributes, but + // we need to keep the hash table up to date ourselves for the + // potentially new qName/index pairs for quick lookup. + int numAtts = atts.getLength(); + if (MAX <= numAtts) + switchOverToHash(numAtts); + + } + + /** + * This method gets the index of an attribute given its uri and locanName. + * @param uri the URI of the attribute name. + * @param localName the local namer (after the ':' ) of the attribute name. + * @return the integer index of the attribute. + * @see org.xml.sax.Attributes#getIndex(String) + */ + public final int getIndex(String uri, String localName) + { + int index; + + if (super.getLength() < MAX) + { + // if we haven't got too many attributes let the + // super class look it up + index = super.getIndex(uri,localName); + return index; + } + // we have too many attributes and the super class is slow + // so find it quickly using our Hashtable. + // Form the key of format "{uri}localName" + m_buff.setLength(0); + m_buff.append('{').append(uri).append('}').append(localName); + String key = m_buff.toString(); + Integer i = (Integer)m_indexFromQName.get(key); + if (i == null) + index = -1; + else + index = i.intValue(); + return index; + } +} |