// HTMLParser Library $Name: v1_6_20060319 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2004 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/lexer/PageAttribute.java,v $
// $Author: derrickoswald $
// $Date: 2005/05/15 11:49:04 $
// $Revision: 1.4 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
package org.htmlparser.lexer;
import org.htmlparser.Attribute;
/**
* An attribute within a tag on a page.
* This attribute is similar to Attribute but 'lazy loaded' from the
* <code>Page</code> by providing the page and cursor offsets
* into the page for the name and value. This is done for speed, since
* if the name and value are not needed we can avoid the cost and memory
* overhead of creating the strings.
* <p>
* Thus the property getters, defer to the base class unless the property
* is null, in which case an attempt is made to read it from the underlying
* page. Optimizations in the predicates and length calculation defer the
* actual instantiation of strings until absolutely needed.
*/
public class PageAttribute
extends
Attribute
{
/**
* The page this attribute is extracted from.
*/
protected Page mPage;
/**
* The starting offset of the name within the page.
* If negative, the name is considered <code>null</code>.
*/
protected int mNameStart;
/**
* The ending offset of the name within the page.
*/
protected int mNameEnd;
/**
* The starting offset of the value within the page.
* If negative, the value is considered <code>null</code>.
*/
protected int mValueStart;
/**
* The ending offset of the name within the page.
*/
protected int mValueEnd;
/**
* Create an attribute.
* @param page The page containing the attribute.
* @param name_start The starting offset of the name within the page.
* If this is negative, the name is considered null.
* @param name_end The ending offset of the name within the page.
* @param value_start he starting offset of the value within the page.
* If this is negative, the value is considered null.
* @param value_end The ending offset of the value within the page.
* @param quote The quote, if any, surrounding the value of the attribute,
* (i.e. ' or "), or zero if none.
*/
public PageAttribute (Page page, int name_start, int name_end, int value_start, int value_end, char quote)
{
mPage = page;
mNameStart = name_start;
mNameEnd = name_end;
mValueStart = value_start;
mValueEnd = value_end;
setName (null);
setAssignment (null);
setValue (null);
setQuote (quote);
}
//
// provide same constructors as super class
//
private void init ()
{
mPage = null;
mNameStart = -1;
mNameEnd = -1;
mValueStart = -1;
mValueEnd = -1;
}
/**
* Create an attribute with the name, assignment string, value and quote given.
* If the quote value is zero, assigns the value using {@link #setRawValue}
* which sets the quote character to a proper value if necessary.
* @param name The name of this attribute.
* @param assignment The assignment string of this attribute.
* @param value The value of this attribute.
* @param quote The quote around the value of this attribute.
*/
public PageAttribute (String name, String assignment, String value, char quote)
{
super (name, assignment, value, quote);
init ();
}
/**
* Create an attribute with the name, value and quote given.
* Uses an equals sign as the assignment string if the value is not
* <code>null</code>, and calls {@link #setRawValue} to get the
* correct quoting if <code>quote</code> is zero.
* @param name The name of this attribute.
* @param value The value of this attribute.
* @param quote The quote around the value of this attribute.
*/
public PageAttribute (String name, String value, char quote)
{
super (name, value, quote);
init ();
}
/**
* Create a whitespace attribute with the value given.
* @param value The value of this attribute.
* @exception IllegalArgumentException if the value contains other than
* whitespace. To set a real value use {@link #PageAttribute(String,String)}.
*/
public PageAttribute (String value)
throws
IllegalArgumentException
{
super (value);
init ();
}
/**
* Create an attribute with the name and value given.
* Uses an equals sign as the assignment string if the value is not
* <code>null</code>, and calls {@link #setRawValue} to get the
* correct quoting.
* @param name The name of this attribute.
* @param value The value of this attribute.
*/
public PageAttribute (String name, String value)
{
super (name, value);
init ();
}
/**
* Create an attribute with the name, assignment string and value given.
* Calls {@link #setRawValue} to get the correct quoting.
* @param name The name of this attribute.
* @param assignment The assignment string of this attribute.
* @param value The value of this attribute.
*/
public PageAttribute (String name, String assignment, String value)
{
super (name, assignment, value);
init ();
}
/**
* Create an empty attribute.
* This will provide "" from the {@link #toString} and
* {@link #toString(StringBuffer)} methods.
*/
public PageAttribute ()
{
super ();
init ();
}
/**
* Get the name of this attribute.
* The part before the equals sign, or the contents of the
* stand-alone attribute.
* @return The name, or <code>null</code> if it's just a whitepace
* 'attribute'.
*/
public String getName ()
{
String ret;
ret = super.getName ();
if (null == ret)
{
if ((null != mPage) && (0 <= mNameStart))
{
ret = mPage.getText (mNameStart, mNameEnd);
setName (ret); // cache the value
}
}
return (ret);
}
/**
* Get the name of this attribute.
* @param buffer The buffer to place the name in.
* @see #getName()
*/
public void getName (StringBuffer buffer)
{
String name;
name = super.getName ();
if (null == name)
{
if ((null != mPage) && (0 <= mNameStart))
mPage.getText (buffer, mNameStart, mNameEnd);
}
else
buffer.append (name);
}
/**
* Get the assignment string of this attribute.
* This is usually just an equals sign, but in poorly formed attributes it
* can include whitespace on either or both sides of an equals sign.
* @return The assignment string.
*/
public String getAssignment ()
{
String ret;
ret = super.getAssignment ();
if (null == ret)
{
if ((null != mPage) && (0 <= mNameEnd) && (0 <= mValueStart))
{
ret = mPage.getText (mNameEnd, mValueStart);
// remove a possible quote included in the assignment
// since mValueStart points at the real start of the value
if (ret.endsWith ("\"") || ret.endsWith ("'"))
ret = ret.substring (0, ret.length () - 1);
setAssignment (ret); // cache the value
}
}
return (ret);
}
/**
* Get the assignment string of this attribute.
* @param buffer The buffer to place the assignment string in.
* @see #getAssignment()
*/
public void getAssignment (StringBuffer buffer)
{
int length;
char ch;
String assignment;
assignment = super.getAssignment ();
if (null == assignment)
{
if ((null != mPage) && (0 <= mNameEnd) && (0 <= mValueStart))
{
mPage.getText (buffer, mNameEnd, mValueStart);
// remove a possible quote included in the assignment
// since mValueStart points at the real start of the value
length = buffer.length () - 1;
ch = buffer.charAt (length);
if (('\'' == ch) || ('"' == ch))
buffer.setLength (length);
}
}
else
buffer.append (assignment);
}
/**
* Get the value of the attribute.
* The part after the equals sign, or the text if it's just a whitepace
* 'attribute'.
* <em>NOTE:</em> This does not include any quotes that may have enclosed
* the value when it was read. To get the un-stripped value use
* {@link #getRawValue}.
* @return The value, or <code>null</code> if it's a stand-alone or
* empty attribute, or the text if it's just a whitepace 'attribute'.
*/
public String getValue ()
{
String ret;
ret = super.getValue ();
if (null == ret)
{
if ((null != mPage) && (0 <= mValueEnd))
{
ret = mPage.getText (mValueStart, mValueEnd);
setValue (ret); // cache the value
}
}
return (ret);
}
/**
* Get the value of the attribute.
* @param buffer The buffer to place the value in.
* @see #getValue()
*/
public void getValue (StringBuffer buffer)
{
String value;
value = super.getValue ();
if (null == value)
{
if ((null != mPage) && (0 <= mValueEnd))
mPage.getText (buffer, mNameStart, mNameEnd);
}
else
buffer.append (value);
}
/**
* Get the raw value of the attribute.
* The part after the equals sign, or the text if it's just a whitepace
* 'attribute'. This includes the quotes around the value if any.
* @return The value, or <code>null</code> if it's a stand-alone attribute,
* or the text if it's just a whitepace 'attribute'.
*/
public String getRawValue ()
{
char quote;
StringBuffer buffer;
String ret;
ret = getValue ();
if (null != ret && (0 != (quote = getQuote ())))
{
buffer = new StringBuffer (ret.length() + 2);
buffer.append (quote);
buffer.append (ret);
buffer.append (quote);
ret = buffer.toString ();
}
return (ret);
}
/**
* Get the raw value of the attribute.
* The part after the equals sign, or the text if it's just a whitepace
* 'attribute'. This includes the quotes around the value if any.
* @param buffer The string buffer to append the attribute value to.
* @see #getRawValue()
*/
public void getRawValue (StringBuffer buffer)
{
char quote;
if (null == mValue)
{
if (0 <= mValueEnd)
{
if (0 != (quote = getQuote ()))
buffer.append (quote);
if (mValueStart != mValueEnd)
mPage.getText (buffer, mValueStart, mValueEnd);
if (0 != quote)
buffer.append (quote);
}
}
else
{
if (0 != (quote = getQuote ()))
buffer.append (quote);
buffer.append (mValue);
if (0 != quote)
buffer.append (quote);
}
}
/**
* Get the page this attribute is anchored to, if any.
* @return The page used to construct this attribute, or null if this
* is just a regular attribute.
*/
public Page getPage ()
{
return (mPage);
}
/**
* Set the page this attribute is anchored to.
* @param page The page to be used to construct this attribute.
* Note: If you set this you probably also want to uncache the property
* values by setting them to null.
*/
public void setPage (Page page)
{
mPage = page;
}
/**
* Get the starting position of the attribute name.
* @return The offset into the page at which the name begins.
*/
public int getNameStartPosition ()
{
return (mNameStart);
}
/**
* Set the starting position of the attribute name.
* @param start The new offset into the page at which the name begins.
*/
public void setNameStartPosition (int start)
{
mNameStart = start;
setName (null); // uncache value
}
/**
* Get the ending position of the attribute name.
* @return The offset into the page at which the name ends.
*/
public int getNameEndPosition ()
{
return (mNameEnd);
}
/**
* Set the ending position of the attribute name.
* @param end The new offset into the page at which the name ends.
*/
public void setNameEndPosition (int end)
{
mNameEnd = end;
setName (null); // uncache value
setAssignment (null); // uncache value
}
/**
* Get the starting position of the attribute value.
* @return The offset into the page at which the value begins.
*/
public int getValueStartPosition ()
{
return (mValueStart);
}
/**
* Set the starting position of the attribute value.
* @param start The new offset into the page at which the value begins.
*/
public void setValueStartPosition (int start)
{
mValueStart = start;
setAssignment (null); // uncache value
setValue (null); // uncache value
}
/**
* Get the ending position of the attribute value.
* @return The offset into the page at which the value ends.
*/
public int getValueEndPosition ()
{
return (mValueEnd);
}
/**
* Set the ending position of the attribute value.
* @param end The new offset into the page at which the value ends.
*/
public void setValueEndPosition (int end)
{
mValueEnd = end;
setValue (null); // uncache value
}
/**
* Predicate to determine if this attribute is whitespace.
* @return <code>true</code> if this attribute is whitespace,
* <code>false</code> if it is a real attribute.
*/
public boolean isWhitespace ()
{
return (((null == super.getName ()) && (null == mPage))
|| ((null != mPage) && (0 > mNameStart)));
}
/**
* Predicate to determine if this attribute has no equals sign (or value).
* @return <code>true</code> if this attribute is a standalone attribute.
* <code>false</code> if has an equals sign.
*/
public boolean isStandAlone ()
{
return (!isWhitespace () // not whitespace
&& (null == super.getAssignment ()) // and no explicit assignment provided
&& !isValued () // and has no value
&& ((null == mPage) // and either its not coming from a page
// or it is coming from a page and it doesn't have an assignment part
|| ((null != mPage) && (0 <= mNameEnd) && (0 > mValueStart))));
}
/**
* Predicate to determine if this attribute has an equals sign but no value.
* @return <code>true</code> if this attribute is an empty attribute.
* <code>false</code> if has an equals sign and a value.
*/
public boolean isEmpty ()
{
return (!isWhitespace () // not whitespace
&& !isStandAlone () // and not standalone
&& (null == super.getValue ()) // and no explicit value provided
&& ((null == mPage) // and either its not coming from a page
// or it is coming from a page and has no value
|| ((null != mPage) && (0 > mValueEnd))));
}
/**
* Predicate to determine if this attribute has a value.
* @return <code>true</code> if this attribute has a value.
* <code>false</code> if it is empty or standalone.
*/
public boolean isValued ()
{
return ((null != super.getValue ()) // an explicit value provided
// or it is coming from a page and has a non-empty value
|| ((null != mPage) && ((0 <= mValueStart) && (0 <= mValueEnd)) && (mValueStart != mValueEnd)));
}
/**
* Get the length of the string value of this attribute.
* @return The number of characters required to express this attribute.
*/
public int getLength ()
{
String name;
String assignment;
String value;
char quote;
int ret;
ret = 0;
name = super.getName ();
if (null != name)
ret += name.length ();
else if ((null != mPage) && (0 <= mNameStart) && (0 <= mNameEnd))
ret += mNameEnd - mNameStart;
assignment = super.getAssignment ();
if (null != assignment)
ret += assignment.length ();
else if ((null != mPage) && (0 <= mNameEnd) && (0 <= mValueStart))
ret += mValueStart - mNameEnd;
value = super.getValue ();
if (null != value)
ret += value.length ();
else if ((null != mPage) && (0 <= mValueStart) && (0 <= mValueEnd))
ret += mValueEnd - mValueStart;
quote = getQuote ();
if (0 != quote)
ret += 2;
return (ret);
}
}