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java.lang.ObjectRenderer
public final class Renderer
Performs a simple rendering of HTML markup into text.
This provides a human readable version of the segment content that is modelled on the way Mozilla Thunderbird and other email clients provide an automatic conversion of HTML content to text in their alternative MIME encoding of emails.
The output using default settings complies with the "text/plain; format=flowed" (DelSp=No) protocol described in RFC3676.
Many properties are available to customise the output, possibly the most significant of which being MaxLineLength
.
See the individual property descriptions for details.
Use one of the following methods to obtain the output:
The rendering of some constructs, especially tables, is very rudimentary. No attempt is made to render nested tables properly, except to ensure that all of the text content is included in the output.
Rendering an entire Source
object performs a full sequential parse automatically.
Any aspect of the algorithm not specifically mentioned here is subject to change without notice in future versions.
To extract pure text without any rendering of the markup, use the TextExtractor
class instead.
Constructor Summary | |
---|---|
Renderer(Segment segment)
Constructs a new Renderer based on the specified Segment . |
Method Summary | |
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int |
getBlockIndentSize()
Returns the size of the indent to be used for anything other than LI elements. |
boolean |
getConvertNonBreakingSpaces()
Indicates whether non-breaking space ( ) character entity references are converted to spaces. |
boolean |
getDecorateFontStyles()
Indicates whether decoration characters are to be included around the content of some font style elements and phrase elements. |
long |
getEstimatedMaximumOutputLength()
Returns the estimated maximum number of characters in the output, or -1 if no estimate is available. |
char[] |
getListBullets()
Returns the bullet characters to use for list items inside UL elements. |
int |
getListIndentSize()
Returns the size of the indent to be used for LI elements. |
int |
getMaxLineLength()
Returns the column at which lines are to be wrapped. |
java.lang.String |
getNewLine()
Returns the string to be used to represent a newline in the output. |
java.lang.String |
getTableCellSeparator()
Returns the string that is to separate table cells. |
Renderer |
setBlockIndentSize(int blockIndentSize)
Sets the size of the indent to be used for anything other than LI elements. |
Renderer |
setConvertNonBreakingSpaces(boolean convertNonBreakingSpaces)
Sets whether non-breaking space ( ) character entity references are converted to spaces. |
Renderer |
setDecorateFontStyles(boolean decorateFontStyles)
Sets whether decoration characters are to be included around the content of some font style elements and phrase elements. |
Renderer |
setListBullets(char[] listBullets)
Sets the bullet characters to use for list items inside UL elements. |
Renderer |
setListIndentSize(int listIndentSize)
Sets the size of the indent to be used for LI elements. |
Renderer |
setMaxLineLength(int maxLineLength)
Sets the column at which lines are to be wrapped. |
Renderer |
setNewLine(java.lang.String newLine)
Sets the string to be used to represent a newline in the output. |
Renderer |
setTableCellSeparator(java.lang.String tableCellSeparator)
Sets the string that is to separate table cells. |
java.lang.String |
toString()
Returns the output as a string. |
void |
writeTo(java.io.Writer writer)
Writes the output to the specified Writer . |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public Renderer(Segment segment)
Renderer
based on the specified Segment
.
segment
- the segment containing the HTML to be rendered.Segment.getRenderer()
Method Detail |
---|
public void writeTo(java.io.Writer writer) throws java.io.IOException
CharStreamSource
Writer
.
writeTo
in interface CharStreamSource
writer
- the destination java.io.Writer
for the output.
java.io.IOException
- if an I/O exception occurs.public long getEstimatedMaximumOutputLength()
CharStreamSource
-1
if no estimate is available.
The returned value should be used as a guide for efficiency purposes only, for example to set an initial StringBuffer
capacity.
There is no guarantee that the length of the output is indeed less than this value,
as classes implementing this method often use assumptions based on typical usage to calculate the estimate.
getEstimatedMaximumOutputLength
in interface CharStreamSource
-1
if no estimate is available.public java.lang.String toString()
CharStreamSource
toString
in interface CharStreamSource
toString
in class java.lang.Object
public Renderer setMaxLineLength(int maxLineLength)
Lines that would otherwise exceed this length are wrapped onto a new line at a word boundary.
A Line may still exceed this length if it consists of a single word, where the length of the word plus the line indent exceeds the maximum length. In this case the line is wrapped immediately after the end of the word.
The default value is 76
, which reflects the maximum line length for sending
email data specified in RFC2049 section 3.5.
maxLineLength
- the column at which lines are to be wrapped.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getMaxLineLength()
public int getMaxLineLength()
See the setMaxLineLength(int)
method for a full description of this property.
public Renderer setNewLine(java.lang.String newLine)
The default value is "\r\n"
(CR+LF) regardless of the platform on which the library is running.
This is so that the default configuration produces valid
MIME plain/text output, which mandates the use of CR+LF for line breaks.
Specifying a null
argument causes the output to use same new line string as is used in the source document, which is
determined via the Source.getNewLine()
method.
If the source document does not contain any new lines, a "best guess" is made by either taking the new line string of a previously parsed document,
or using the value from Config.NewLine
.
newLine
- the string to be used to represent a newline in the output, may be null
.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getNewLine()
public java.lang.String getNewLine()
See the setNewLine(String)
method for a full description of this property.
public Renderer setDecorateFontStyles(boolean decorateFontStyles)
The default value is false
.
Below is a table summarising the decorated elements.
Elements | Character | Example Output |
---|---|---|
B and STRONG | * | *bold text* |
I and EM | / | /italic text/ |
U | _ | _underlined text_ |
CODE | | | |code| |
decorateFontStyles
- specifies whether decoration characters are to be included around the content of some font style elements.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getDecorateFontStyles()
public boolean getDecorateFontStyles()
See the setDecorateFontStyles(boolean)
method for a full description of this property.
true
if decoration characters are to be included around the content of some font style elements, otherwise false
.public Renderer setConvertNonBreakingSpaces(boolean convertNonBreakingSpaces)
) character entity references are converted to spaces.
The default value is true
.
convertNonBreakingSpaces
- specifies whether non-breaking space (
) character entity references are converted to spaces.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getConvertNonBreakingSpaces()
public boolean getConvertNonBreakingSpaces()
) character entity references are converted to spaces.
See the setConvertNonBreakingSpaces(boolean)
method for a full description of this property.
true
if non-breaking space (
) character entity references are converted to spaces, otherwise false
.public Renderer setBlockIndentSize(int blockIndentSize)
LI
elements.
At present this applies to BLOCKQUOTE
and DD
elements.
The default value is 4
.
blockIndentSize
- the size of the indent.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getBlockIndentSize()
public int getBlockIndentSize()
LI
elements.
See the setBlockIndentSize(int)
method for a full description of this property.
LI
elements.public Renderer setListIndentSize(int listIndentSize)
LI
elements.
The default value is 6
.
This applies to LI
elements inside both UL
and OL
elements.
The bullet or number of the list item is included as part of the indent.
listIndentSize
- the size of the indent.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getListIndentSize()
public int getListIndentSize()
LI
elements.
See the setListIndentSize(int)
method for a full description of this property.
LI
elements.public Renderer setListBullets(char[] listBullets)
UL
elements.
The values in the default array are *
, o
, +
and #
.
If the nesting of rendered lists goes deeper than the length of this array, the bullet characters start repeating from the first in the array.
WARNING: If any of the characters in the default array are modified, this will affect all other instances of this class using the default array.
listBullets
- an array of characters to be used as bullets, must have at least one entry.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getListBullets()
public char[] getListBullets()
UL
elements.
See the setListBullets(char[])
method for a full description of this property.
UL
elements.public Renderer setTableCellSeparator(java.lang.String tableCellSeparator)
The default value is " \t"
(a space followed by a tab).
tableCellSeparator
- the string that is to separate table cells.
Renderer
instance, allowing multiple property setting methods to be chained in a single statement.getTableCellSeparator()
public java.lang.String getTableCellSeparator()
See the setTableCellSeparator(String)
method for a full description of this property.
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