| /* |
| * 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: AttributesImplSerializer.java 468654 2006-10-28 07:09:23Z minchau $ |
| */ |
| |
| package org.apache.xml.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; |
| } |
| } |