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	/*
	* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
	*/
	/*
	* 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,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.HashMap;
	import java.util.Map;
	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 Map 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 Map<String, Integer> m_indexFromQName = new HashMap<>();

	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 Map.
	*/
	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 Map.
	Integer i = 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 = 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);
	}
	}

	/**
	* 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 Map, so we now update the Map.
	* Future additional attributes will update the Map 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 = 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 Map, then clear the Map 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 Map.
	// 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 = m_indexFromQName.get(key);
	if (i == null)
	index = -1;
	else
	index = i;
	return index;
	}
	}

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