/*
* 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 Also: - Attributes
@xsl.usage internal
/**
* 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".
/**
* 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.
/**
* 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.
/**
* 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.
Params: - qname – the qualified name of the attribute, e.g. "prefix1:locName1"
See Also: Returns: the integer index of the attribute.
/**
* 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).
Params: - uri – the URI of the attribute
- local – the local name of the attribute
- qname – the qualified name of the attribute
- type – the type of the attribute
- val – the value of the attribute
See Also:
/**
* 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.
Params: - numAtts –
/**
* 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 Also: - clear.clear()
/**
* 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).
Params: - atts – the attributes to copy into these attributes.
See Also:
/**
* 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.
Params: - uri – the URI of the attribute name.
- localName – the local namer (after the ':' ) of the attribute name.
See Also: Returns: the integer index of the attribute.
/**
* 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;
}
}