sboag 00/02/17 07:44:31
Added: src/org/apache/xalan/xpath/xml MutableAttrListImpl.java
Log:
Faster attribute list implemenation.
Revision Changes Path
1.1
xml-xalan/src/org/apache/xalan/xpath/xml/MutableAttrListImpl.java
Index: MutableAttrListImpl.java
===================================================================
package org.apache.xalan.xpath.xml;
import org.apache.xalan.xpath.xml.StringVector;
import org.xml.sax.AttributeList;
import java.io.Serializable;
public class MutableAttrListImpl extends StringVector implements
AttributeList, Serializable
{
static final int OFFSET_NAME = 0;
static final int OFFSET_TYPE = 1;
static final int OFFSET_VALUE = 2;
static final int SLOTS_PER_ATTR = 3;
/**
* Create an empty attribute list.
*
* <p>This constructor is most useful for parser writers, who
* will use it to create a single, reusable attribute list that
* can be reset with the clear method between elements.</p>
*
* @see #addAttribute
* @see #clear
*/
public MutableAttrListImpl ()
{
}
/**
* Construct a persistent copy of an existing attribute list.
*
* <p>This constructor is most useful for application writers,
* who will use it to create a persistent copy of an existing
* attribute list.</p>
*
* @param atts The attribute list to copy
* @see org.xml.sax.DocumentHandler#startElement
*/
public MutableAttrListImpl (AttributeList atts)
{
setAttributeList(atts);
}
////////////////////////////////////////////////////////////////////
// Methods specific to this class.
////////////////////////////////////////////////////////////////////
/**
* Set the attribute list, discarding previous contents.
*
* <p>This method allows an application writer to reuse an
* attribute list easily.</p>
*
* @param atts The attribute list to copy.
*/
public void setAttributeList (AttributeList atts)
{
int count = atts.getLength();
clear();
for (int i = 0; i < count; i++)
{
addAttribute(atts.getName(i), atts.getType(i), atts.getValue(i));
}
}
/**
* Add an attribute to an attribute list.
*
* <p>This method is provided for SAX parser writers, to allow them
* to build up an attribute list incrementally before delivering
* it to the application.</p>
*
* @param name The attribute name.
* @param type The attribute type ("NMTOKEN" for an enumeration).
* @param value The attribute value (must not be null).
* @see #removeAttribute
* @see org.xml.sax.DocumentHandler#startElement
*/
public void addAttribute (String name, String type, String value)
{
// removeAttribute (name); // I think this is correct, but I don't think
I need it
if((m_firstFree+SLOTS_PER_ATTR) >= m_mapSize)
{
m_mapSize+=m_blocksize;
String newMap[] = new String[m_mapSize];
System.arraycopy(m_map, 0, newMap, 0, m_firstFree+1);
m_map = newMap;
}
m_map[m_firstFree+OFFSET_NAME] = name;
m_map[m_firstFree+OFFSET_TYPE] = type;
m_map[m_firstFree+OFFSET_VALUE] = value;
m_firstFree+=SLOTS_PER_ATTR;
}
/**
* Remove an attribute from the list.
*
* <p>SAX application writers can use this method to filter an
* attribute out of an AttributeList. Note that invoking this
* method will change the length of the attribute list and
* some of the attribute's indices.</p>
*
* <p>If the requested attribute is not in the list, this is
* a no-op.</p>
*
* @param name The attribute name.
* @see #addAttribute
*/
public void removeAttribute (String name)
{
for(int i = 0; i < m_firstFree; i++)
{
if(m_map[i+OFFSET_NAME].equals(name))
{
if(i > m_firstFree)
System.arraycopy(m_map, i+SLOTS_PER_ATTR, m_map, i-SLOTS_PER_ATTR,
m_firstFree-i);
else
{
m_map[i+OFFSET_NAME] = null;
m_map[i+OFFSET_TYPE] = null;
m_map[i+OFFSET_VALUE] = null;
}
m_firstFree-=SLOTS_PER_ATTR;
return;
}
}
}
/**
* Clear the attribute list.
*
* <p>SAX parser writers can use this method to reset the attribute
* list between DocumentHandler.startElement events. Normally,
* it will make sense to reuse the same MutableAttrListImpl object
* rather than allocating a new one each time.</p>
*
* @see org.xml.sax.DocumentHandler#startElement
*/
public void clear ()
{
for(int i = 0; i < m_firstFree; i++)
{
m_map[i] = null;
}
m_firstFree = 0;
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.AttributeList
////////////////////////////////////////////////////////////////////
/**
* Return the number of attributes in the list.
*
* @return The number of attributes in the list.
* @see org.xml.sax.AttributeList#getLength
*/
public int getLength ()
{
return (m_firstFree > 0) ? (m_firstFree/SLOTS_PER_ATTR) : 0;
}
/**
* Get the name of an attribute (by position).
*
* @param i The position of the attribute in the list.
* @return The attribute name as a string, or null if there
* is no attribute at that position.
* @see org.xml.sax.AttributeList#getName(int)
*/
public String getName (int i)
{
if (i < 0)
{
return null;
}
try
{
return m_map[(i*SLOTS_PER_ATTR)+OFFSET_NAME];
}
catch (ArrayIndexOutOfBoundsException e)
{
return null;
}
}
/**
* Get the type of an attribute (by position).
*
* @param i The position of the attribute in the list.
* @return The attribute type as a string ("NMTOKEN" for an
* enumeration, and "CDATA" if no declaration was
* read), or null if there is no attribute at
* that position.
* @see org.xml.sax.AttributeList#getType(int)
*/
public String getType (int i)
{
if (i < 0)
{
return null;
}
try
{
return m_map[(i*SLOTS_PER_ATTR)+OFFSET_TYPE];
}
catch (ArrayIndexOutOfBoundsException e)
{
return null;
}
}
/**
* Get the value of an attribute (by position).
*
* @param i The position of the attribute in the list.
* @return The attribute value as a string, or null if
* there is no attribute at that position.
* @see org.xml.sax.AttributeList#getValue(int)
*/
public String getValue (int i)
{
if (i < 0)
{
return null;
}
try
{
return m_map[(i*SLOTS_PER_ATTR)+OFFSET_VALUE];
}
catch (ArrayIndexOutOfBoundsException e)
{
return null;
}
}
/**
* Get the type of an attribute (by name).
*
* @param name The attribute name.
* @return The attribute type as a string ("NMTOKEN" for an
* enumeration, and "CDATA" if no declaration was
* read).
* @see org.xml.sax.AttributeList#getType(java.lang.String)
*/
public String getType (String name)
{
for(int i = 0; i <= m_firstFree; i++)
{
if(m_map[i+OFFSET_NAME].equals(name))
{
return m_map[i+OFFSET_TYPE];
}
}
return "CDATA";
}
/**
* Get the value of an attribute (by name).
*
* @param name The attribute name.
* @see org.xml.sax.AttributeList#getValue(java.lang.String)
*/
public String getValue (String name)
{
for(int i = 0; i <= m_firstFree; i++)
{
if(m_map[i+OFFSET_NAME].equals(name))
{
return m_map[i+OFFSET_NAME];
}
}
return null;
}
}
// end of MutableAttrListImpl.java
