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// HTMLParser Library $Name: v1_5 $ - 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/Attribute.java,v $
// $Author: derrickoswald $
// $Date: 2005/05/15 11:49:03 $
// $Revision: 1.7 $
//
// 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;
import java.io.Serializable;
/**
* An attribute within a tag.
* Holds the name, assignment string, value and quote character.
*
* This class was made deliberately simple. Except for
* {@link #setRawValue RawValue}, the properties are completely orthogonal,
* that is: each property is independant of the others. This means you have
* enough rope here to hang yourself, and it's very easy to create
* malformed HTML. Where it's obvious, warnings and notes have been provided
* in the setters javadocs, but it is up to you -- the programmer --
* to ensure that the contents of the four fields will yield valid HTML
* (if that's what you want).
*
* Be especially mindful of quotes and assignment strings. These are handled
* by the constructors where it's obvious, but in general, you need to set
* them explicitly when building an attribute. For example to construct
* the attribute label="A multi word value." you could use:
*
* attribute = new Attribute ();
* attribute.setName ("label");
* attribute.setAssignment ("=");
* attribute.setValue ("A multi word value.");
* attribute.setQuote ('"');
*
* or
*
* attribute = new Attribute ();
* attribute.setName ("label");
* attribute.setAssignment ("=");
* attribute.setRawValue ("A multi word value.");
*
* or
*
* attribute = new Attribute ("label", "A multi word value.");
*
* Note that the assignment value and quoting need to be set separately when
* building the attribute from scratch using the properties.
*
*
* Valid States for Attributes.
*
* Description
* toString()
* Name
* Assignment
* Value
* Quote
*
*
* whitespace attribute
* value
* nullnull"value"
* 0
*
* standalone attribute
* name
* "name"
* nullnull0
*
* empty attribute
* name=
* "name"
* "="
* null0
*
* empty single quoted attribute
* name=''
* "name"
* "="
* null'
*
* empty double quoted attribute
* name=""
* "name"
* "="
* null"
*
* naked attribute
* name=value
* "name"
* "="
* "value"
* 0
*
* single quoted attribute
* name='value'
* "name"
* "="
* "value"
* '
*
* double quoted attribute
* name="value"
* "name"
* "="
* "value"
* "
*
*
In words:
*
If Name is null, and Assignment is null, and Quote is zero,
* it's whitepace and Value has the whitespace text -- value
*
If Name is not null, and both Assignment and Value are null
* it's a standalone attribute -- name
*
If Name is not null, and Assignment is an equals sign, and Quote is zero
* it's an empty attribute -- name=
*
If Name is not null, and Assignment is an equals sign,
* and Value is "" or null, and Quote is '
* it's an empty single quoted attribute -- name=''
*
If Name is not null, and Assignment is an equals sign,
* and Value is "" or null, and Quote is "
* it's an empty double quoted attribute -- name=""
*
If Name is not null, and Assignment is an equals sign,
* and Value is something, and Quote is zero
* it's a naked attribute -- name=value
*
If Name is not null, and Assignment is an equals sign,
* and Value is something, and Quote is '
* it's a single quoted attribute -- name='value'
*
If Name is not null, and Assignment is an equals sign,
* and Value is something, and Quote is "
* it's a double quoted attribute -- name="value"
*
All other states are invalid HTML.
*
* From the
* HTML 4.01 Specification, W3C Recommendation 24 December 1999
* http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2:
*
* 3.2.2 Attributes
* Elements may have associated properties, called attributes, which may
* have values (by default, or set by authors or scripts). Attribute/value
* pairs appear before the final ">" of an element's start tag. Any number
* of (legal) attribute value pairs, separated by spaces, may appear in an
* element's start tag. They may appear in any order.
* In this example, the id attribute is set for an H1 element:
*
*
* {@.html
*
* This is an identified heading thanks to the id attribute
*
}
*
*
* By default, SGML requires that all attribute values be delimited using
* either double quotation marks (ASCII decimal 34) or single quotation
* marks (ASCII decimal 39). Single quote marks can be included within the
* attribute value when the value is delimited by double quote marks, and
* vice versa. Authors may also use numeric character references to
* represent double quotes (") and single quotes (').
* For doublequotes authors can also use the character entity reference
* ".
* In certain cases, authors may specify the value of an attribute without
* any quotation marks. The attribute value may only contain letters
* (a-z and A-Z), digits (0-9), hyphens (ASCII decimal 45),
* periods (ASCII decimal 46), underscores (ASCII decimal 95),
* and colons (ASCII decimal 58). We recommend using quotation marks even
* when it is possible to eliminate them.
* Attribute names are always case-insensitive.
* Attribute values are generally case-insensitive. The definition of each
* attribute in the reference manual indicates whether its value is
* case-insensitive.
* All the attributes defined by this specification are listed in the
* attribute
* index.
*
*
*/
public class Attribute
implements
Serializable
{
/**
* The name of this attribute.
* The part before the equals sign, or the stand-alone attribute.
* This will be null if the attribute is whitespace.
*/
protected String mName;
/**
* The assignment string of the attribute.
* The equals sign.
* This will be null if the attribute is a
* stand-alone attribute.
*/
protected String mAssignment;
/**
* The value of the attribute.
* The part after the equals sign.
* This will be null if the attribute is an empty or
* stand-alone attribute.
*/
protected String mValue;
/**
* The quote, if any, surrounding the value of the attribute, if any.
* This will be zero if there are no quotes around the value.
*/
protected char mQuote;
/**
* Create an attribute with the name, assignment, 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 Attribute (String name, String assignment, String value, char quote)
{
setName (name);
setAssignment (assignment);
if (0 == quote)
setRawValue (value);
else
{
setValue (value);
setQuote (quote);
}
}
/**
* Create an attribute with the name, value and quote given.
* Uses an equals sign as the assignment string if the value is not
* null, and calls {@link #setRawValue} to get the
* correct quoting if quote 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 Attribute (String name, String value, char quote)
{
this (name, (null == value ? "" : "="), value, quote);
}
/**
* 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 #Attribute(String,String)}.
*/
public Attribute (String value)
throws
IllegalArgumentException
{
if (0 != value.trim ().length ())
throw new IllegalArgumentException ("non whitespace value");
else
{
setName (null);
setAssignment (null);
setValue (value);
setQuote ((char)0);
}
}
/**
* Create an attribute with the name and value given.
* Uses an equals sign as the assignment string if the value is not
* null, and calls {@link #setRawValue} to get the
* correct quoting.
* @param name The name of this attribute.
* @param value The value of this attribute.
*/
public Attribute (String name, String value)
{
this (name, (null == value ? "" : "="), value, (char)0);
}
/**
* 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 Attribute (String name, String assignment, String value)
{
this (name, assignment, value, (char)0);
}
/**
* Create an empty attribute.
* This will provide "" from the {@link #toString} and
* {@link #toString(StringBuffer)} methods.
*/
public Attribute ()
{
this (null, null, null, (char)0);
}
/**
* Get the name of this attribute.
* The part before the equals sign, or the contents of the
* stand-alone attribute.
* @return The name, or null if it's just a whitepace
* 'attribute'.
*/
public String getName ()
{
return (mName);
}
/**
* Get the name of this attribute.
* @param buffer The buffer to place the name in.
* @see #getName()
*/
public void getName (StringBuilder buffer)
{
if (null != mName)
buffer.append (mName);
}
/**
* Set the name of this attribute.
* Set the part before the equals sign, or the contents of the
* stand-alone attribute.
* WARNING: Setting this to null can result in
* malformed HTML if the assignment string is not null.
* @param name The new name.
*/
public void setName (String name)
{
mName = 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 ()
{
return (mAssignment);
}
/**
* Get the assignment string of this attribute.
* @param buffer The buffer to place the assignment string in.
* @see #getAssignment()
*/
public void getAssignment (StringBuilder buffer)
{
if (null != mAssignment)
buffer.append (mAssignment);
}
/**
* Set the assignment string of this attribute.
* WARNING: Setting this property to other than an equals sign
* or null will result in malformed HTML. In the case of a
* null, the {@link #setValue value} should also be set to
* null.
* @param assignment The new assignment string.
*/
public void setAssignment (String assignment)
{
mAssignment = assignment;
}
/**
* Get the value of the attribute.
* The part after the equals sign, or the text if it's just a whitepace
* 'attribute'.
* NOTE: 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 null if it's a stand-alone or
* empty attribute, or the text if it's just a whitepace 'attribute'.
*/
public String getValue ()
{
return (mValue);
}
/**
* Get the value of the attribute.
* @param buffer The buffer to place the value in.
* @see #getValue()
*/
public void getValue (StringBuilder buffer)
{
if (null != mValue)
buffer.append (mValue);
}
/**
* Set the value of the attribute.
* The part after the equals sign, or the text if it's a whitepace
* 'attribute'.
* WARNING: Setting this property to a value that needs to be
* quoted without also setting the quote character will result in malformed
* HTML.
* @param value The new value.
*/
public void setValue (String value)
{
mValue = value;
}
/**
* Get the quote, if any, surrounding the value of the attribute, if any.
* @return Either ' or " if the attribute value was quoted, or zero
* if there are no quotes around it.
*/
public char getQuote ()
{
return (mQuote);
}
/**
* Get the quote, if any, surrounding the value of the attribute, if any.
* @param buffer The buffer to place the quote in.
* @see #getQuote()
*/
public void getQuote (StringBuilder buffer)
{
if (0 != mQuote)
buffer.append (mQuote);
}
/**
* Set the quote surrounding the value of the attribute.
* WARNING: Setting this property to zero will result in malformed
* HTML if the {@link #getValue value} needs to be quoted (i.e. contains
* whitespace).
* @param quote The new quote value.
*/
public void setQuote (char quote)
{
mQuote = quote;
}
/**
* 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 null if it's a stand-alone attribute,
* or the text if it's just a whitepace 'attribute'.
*/
public String getRawValue ()
{
char quote;
StringBuilder buffer;
String ret;
if (isValued ())
{
quote = getQuote ();
if (0 != quote)
{
buffer = new StringBuilder (); // todo: what is the value length?
buffer.append (quote);
getValue (buffer);
buffer.append (quote);
ret = buffer.toString ();
}
else
ret = getValue ();
}
else
ret = null;
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 (StringBuilder buffer)
{
getQuote (buffer);
getValue (buffer);
getQuote (buffer);
}
/**
* Set the value of the attribute and the quote character.
* If the value is pure whitespace, assign it 'as is' and reset the
* quote character. If not, check for leading and trailing double or
* single quotes, and if found use this as the quote character and
* the inner contents of value as the real value.
* Otherwise, examine the string to determine if quotes are needed
* and an appropriate quote character if so. This may involve changing
* double quotes within the string to character references.
* @param value The new value.
*/
public void setRawValue (String value)
{
char ch;
boolean needed;
boolean singleq;
boolean doubleq;
String ref;
StringBuilder buffer;
char quote;
quote = 0;
if ((null != value) && (0 != value.trim ().length ()))
{
if (value.startsWith ("'") && value.endsWith ("'")
&& (2 <= value.length ()))
{
quote = '\'';
value = value.substring (1, value.length () - 1);
}
else if (value.startsWith ("\"") && value.endsWith ("\"")
&& (2 <= value.length ()))
{
quote = '"';
value = value.substring (1, value.length () - 1);
}
else
{
// first determine if there's whitespace in the value
// and while we're at it find a suitable quote character
needed = false;
singleq = true;
doubleq = true;
for (int i = 0; i < value.length (); i++)
{
ch = value.charAt (i);
if ('\'' == ch)
{
singleq = false;
needed = true;
}
else if ('"' == ch)
{
doubleq = false;
needed = true;
}
else if (!('-' == ch) && !('.' == ch) && !('_' == ch)
&& !(':' == ch) && !Character.isLetterOrDigit (ch))
{
needed = true;
}
}
// now apply quoting
if (needed)
{
if (doubleq)
quote = '"';
else if (singleq)
quote = '\'';
else
{
// uh-oh, we need to convert some quotes into character
// references, so convert all double quotes into "
quote = '"';
ref = """; // Translate.encode (quote);
// JDK 1.4: value = value.replaceAll ("\"", ref);
buffer = new StringBuilder (
value.length() * (ref.length () - 1));
for (int i = 0; i < value.length (); i++)
{
ch = value.charAt (i);
if (quote == ch)
buffer.append (ref);
else
buffer.append (ch);
}
value = buffer.toString ();
}
}
}
}
setValue (value);
setQuote (quote);
}
/**
* Predicate to determine if this attribute is whitespace.
* @return true if this attribute is whitespace,
* false if it is a real attribute.
*/
public boolean isWhitespace ()
{
return (null == getName ());
}
/**
* Predicate to determine if this attribute has no equals sign (or value).
* @return true if this attribute is a standalone attribute.
* false if has an equals sign.
*/
public boolean isStandAlone ()
{
return ((null != getName ()) && (null == getAssignment ()));
}
/**
* Predicate to determine if this attribute has an equals sign but no value.
* @return true if this attribute is an empty attribute.
* false if has an equals sign and a value.
*/
public boolean isEmpty ()
{
return ((null != getAssignment ()) && (null == getValue ()));
}
/**
* Predicate to determine if this attribute has a value.
* @return true if this attribute has a value.
* false if it is empty or standalone.
*/
public boolean isValued ()
{
return (null != getValue ());
}
/**
* 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 = getName ();
if (null != name)
ret += name.length ();
assignment = getAssignment ();
if (null != assignment)
ret += assignment.length ();
value = getValue ();
if (null != value)
ret += value.length ();
quote = getQuote ();
if (0 != quote)
ret += 2;
return (ret);
}
/**
* Get a text representation of this attribute.
* Suitable for insertion into a tag, the output is one of
* the forms:
*
*
* value
* name
* name=
* name=value
* name='value'
* name="value"
*
*
* @return A string that can be used within a tag.
*/
public String toString ()
{
int length;
StringBuilder ret;
// get the size to avoid extra StringBuilder allocations
length = getLength ();
ret = new StringBuilder (length);
toString (ret);
return (ret.toString ());
}
/**
* Get a text representation of this attribute.
* @param buffer The accumulator for placing the text into.
* @see #toString()
*/
public void toString (StringBuilder buffer)
{
getName (buffer);
getAssignment (buffer);
getRawValue (buffer);
}
}