Class Attribute
- All Implemented Interfaces:
Serializable
- Direct Known Subclasses:
PageAttribute
This class was made deliberately simple. Except for
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.
Description | toString() | Name | Assignment | Value | Quote |
---|---|---|---|---|---|
whitespace attribute | value | null |
null |
"value" | 0 |
standalone attribute | name | "name" | null |
null |
0 |
empty attribute | name= | "name" | "=" | null |
0 |
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:
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.
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
".
invalid input: '{@'.html
This is an identified heading thanks to the id attribute
}
- See Also:
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionCreate an empty attribute.Create a whitespace attribute with the value given.Create an attribute with the name and value given.Create an attribute with the name, value and quote given.Create an attribute with the name, assignment string and value given.Create an attribute with the name, assignment, value and quote given. -
Method Summary
Modifier and TypeMethodDescriptionGet the assignment string of this attribute.void
getAssignment
(StringBuffer buffer) Get the assignment string of this attribute.int
Get the length of the string value of this attribute.getName()
Get the name of this attribute.void
getName
(StringBuffer buffer) Get the name of this attribute.char
getQuote()
Get the quote, if any, surrounding the value of the attribute, if any.void
getQuote
(StringBuffer buffer) Get the quote, if any, surrounding the value of the attribute, if any.Get the raw value of the attribute.void
getRawValue
(StringBuffer buffer) Get the raw value of the attribute.getValue()
Get the value of the attribute.void
getValue
(StringBuffer buffer) Get the value of the attribute.boolean
isEmpty()
Predicate to determine if this attribute has an equals sign but no value.boolean
Predicate to determine if this attribute has no equals sign (or value).boolean
isValued()
Predicate to determine if this attribute has a value.boolean
Predicate to determine if this attribute is whitespace.void
setAssignment
(String assignment) Set the assignment string of this attribute.void
Set the name of this attribute.void
setQuote
(char quote) Set the quote surrounding the value of the attribute.void
setRawValue
(String value) Set the value of the attribute and the quote character.void
Set the value of the attribute.toString()
Get a text representation of this attribute.void
toString
(StringBuffer buffer) Get a text representation of this attribute.
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Field Details
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mName
The name of this attribute. The part before the equals sign, or the stand-alone attribute. This will benull
if the attribute is whitespace. -
mAssignment
The assignment string of the attribute. The equals sign. This will benull
if the attribute is a stand-alone attribute. -
mValue
The value of the attribute. The part after the equals sign. This will benull
if the attribute is an empty or stand-alone attribute. -
mQuote
protected char mQuoteThe quote, if any, surrounding the value of the attribute, if any. This will be zero if there are no quotes around the value.
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Constructor Details
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Attribute
Create an attribute with the name, assignment, value and quote given. If the quote value is zero, assigns the value usingsetRawValue(java.lang.String)
which sets the quote character to a proper value if necessary.- Parameters:
name
- The name of this attribute.assignment
- The assignment string of this attribute.value
- The value of this attribute.quote
- The quote around the value of this attribute.
-
Attribute
Create an attribute with the name, value and quote given. Uses an equals sign as the assignment string if the value is notnull
, and callssetRawValue(java.lang.String)
to get the correct quoting ifquote
is zero.- Parameters:
name
- The name of this attribute.value
- The value of this attribute.quote
- The quote around the value of this attribute.
-
Attribute
Create a whitespace attribute with the value given.- Parameters:
value
- The value of this attribute.- Throws:
IllegalArgumentException
- if the value contains other than whitespace. To set a real value useAttribute(String,String)
.
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Attribute
Create an attribute with the name and value given. Uses an equals sign as the assignment string if the value is notnull
, and callssetRawValue(java.lang.String)
to get the correct quoting.- Parameters:
name
- The name of this attribute.value
- The value of this attribute.
-
Attribute
Create an attribute with the name, assignment string and value given. CallssetRawValue(java.lang.String)
to get the correct quoting.- Parameters:
name
- The name of this attribute.assignment
- The assignment string of this attribute.value
- The value of this attribute.
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Attribute
public Attribute()Create an empty attribute. This will provide "" from thetoString()
andtoString(StringBuffer)
methods.
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Method Details
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getName
Get the name of this attribute. The part before the equals sign, or the contents of the stand-alone attribute.- Returns:
- The name, or
null
if it's just a whitepace 'attribute'. - See Also:
-
getName
Get the name of this attribute.- Parameters:
buffer
- The buffer to place the name in.- See Also:
-
setName
Set the name of this attribute. Set the part before the equals sign, or the contents of the stand-alone attribute. WARNING: Setting this tonull
can result in malformed HTML if the assignment string is notnull
.- Parameters:
name
- The new name.- See Also:
-
getAssignment
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.- Returns:
- The assignment string.
- See Also:
-
getAssignment
Get the assignment string of this attribute.- Parameters:
buffer
- The buffer to place the assignment string in.- See Also:
-
setAssignment
Set the assignment string of this attribute. WARNING: Setting this property to other than an equals sign ornull
will result in malformed HTML. In the case of anull
, thevalue
should also be set tonull
.- Parameters:
assignment
- The new assignment string.- See Also:
-
getValue
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 usegetRawValue()
.- Returns:
- The value, or
null
if it's a stand-alone or empty attribute, or the text if it's just a whitepace 'attribute'. - See Also:
-
getValue
Get the value of the attribute.- Parameters:
buffer
- The buffer to place the value in.- See Also:
-
setValue
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.- Parameters:
value
- The new value.- See Also:
-
getQuote
public char getQuote()Get the quote, if any, surrounding the value of the attribute, if any.- Returns:
- Either ' or " if the attribute value was quoted, or zero if there are no quotes around it.
- See Also:
-
getQuote
Get the quote, if any, surrounding the value of the attribute, if any.- Parameters:
buffer
- The buffer to place the quote in.- See Also:
-
setQuote
public void setQuote(char quote) Set the quote surrounding the value of the attribute. WARNING: Setting this property to zero will result in malformed HTML if thevalue
needs to be quoted (i.e. contains whitespace).- Parameters:
quote
- The new quote value.- See Also:
-
getRawValue
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.- Returns:
- The value, or
null
if it's a stand-alone attribute, or the text if it's just a whitepace 'attribute'. - See Also:
-
getRawValue
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.- Parameters:
buffer
- The string buffer to append the attribute value to.- See Also:
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setRawValue
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 ofvalue
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.- Parameters:
value
- The new value.- See Also:
-
isWhitespace
public boolean isWhitespace()Predicate to determine if this attribute is whitespace.- Returns:
true
if this attribute is whitespace,false
if it is a real attribute.
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isStandAlone
public boolean isStandAlone()Predicate to determine if this attribute has no equals sign (or value).- Returns:
true
if this attribute is a standalone attribute.false
if has an equals sign.
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isEmpty
public boolean isEmpty()Predicate to determine if this attribute has an equals sign but no value.- Returns:
true
if this attribute is an empty attribute.false
if has an equals sign and a value.
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isValued
public boolean isValued()Predicate to determine if this attribute has a value.- Returns:
true
if this attribute has a value.false
if it is empty or standalone.
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getLength
public int getLength()Get the length of the string value of this attribute.- Returns:
- The number of characters required to express this attribute.
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toString
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"
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toString
Get a text representation of this attribute.- Parameters:
buffer
- The accumulator for placing the text into.- See Also:
-