net.sf.basedb.clients.web.util
Class HTML

java.lang.Object
  net.sf.basedb.clients.web.util.HTML

public class HTML
extends Object

This class contains a set of static methods that may be useful in a web application for handling text/HTML strings.

Version:

2.0

Author:

Nicklas

Field Summary

private static Pattern	AMP
private static Pattern	AMPERSAND
private static Pattern	AT_OR_DOT
private static Pattern	BACKSLASH
private static Pattern	DOUBLE_QUOTE
static Pattern	EMAIL_REGEXP This pattern can be used to find email addresses.
private static Pattern	GT
private static Pattern	HASH
private static Pattern	IMAGE_EXTENSION
private static Pattern	LEADING_TRAILING_LINEBREAKS
static Pattern	LINEBREAKS_REGEXP This pattern can be used to find line breaks.
static int	LINK_EMAIL This flag is used in scanForLinks(String,int) when you want to create links for email addresses.
static int	LINK_URL This flag is used in scanForLinks(String,int) when you want to create links for URL:s.
private static Pattern	LT
static Pattern	MARKUP Pattern that matches everything inside a HTML tag.
private static Pattern	NEWLINE
private static Pattern	PERCENT
private static Pattern	PLUS
private static Pattern	QUOTE
static Pattern	SAFE_TAGS This pattern is a list of HTML tags considered "safe".
private static Pattern	SINGLE_QUOTE
static int	SMART_IMAGES This flag is used in scanForLinks(String,int) when you want to create links for images with a <img> tag instead of an <a> tag.
private static Pattern	SPACE
static Pattern	TAG_REGEXP This pattern can be used to fins HTML tags.
static Pattern	URL_REGEXP This pattern can be used to find URL:s.

Constructor Summary

HTML()

Method Summary

static String	encodeTags(String in) Scans a string for HTML tags and replaces all & with &amp;, < with &lt;, > with &gt; and all " with "
static String	encodeTags(String in, Pattern safeTags)
static String	encodeTags(String in, String safeTags)
static String	formatLineBreaks(String in) Finds all linebreaks in a string and replaces them with a <br> tag, except that leading and trailing linebreaks will be removed.
static boolean	isValidEmail(String email) Checks if the given string looks like an email address.
static boolean	isValidUrl(String url) Checks if the given string looks like an URL.
static String	javaScriptEncode(String in) Escape a string to make it safe for use in a JavaScript statement.
static String	niceFormat(String in) A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, "_new") and formatLineBreaks(in) in a single operation.
static String	niceFormat(String in, int flags) A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, flags, "_new") and formatLineBreaks(in) in a single operation.
static String	niceFormat(String in, int flags, String linkTarget) A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, flags, link_target) and formatLineBreaks(in) in a single operation.
static String	niceFormat(String in, String linkTarget) A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, target) and formatLineBreaks(in) in a single operation.
static String	scanForLinks(String in) Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags.
static String	scanForLinks(String in, int flags) Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags.
static String	scanForLinks(String in, int flags, String target) Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags.
static String	scanForLinks(String in, String target) Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags.
static String	stripMarkup(CharSequence in) Remove all HTML markup in a string and return what is left.
static int	textLength(CharSequence html) Counts the length of a string ignoring all characters in HTML markup tags.
static String	urlEncode(String in) Encode URL-unsafe characters in a string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LINK_URL

public static final int LINK_URL

This flag is used in scanForLinks(String,int) when you want to create links for URL:s.

See Also:

Constant Field Values

LINK_EMAIL

public static final int LINK_EMAIL

This flag is used in scanForLinks(String,int) when you want to create links for email addresses.

See Also:

Constant Field Values

SMART_IMAGES

public static final int SMART_IMAGES

This flag is used in scanForLinks(String,int) when you want to create links for images with a <img> tag instead of an <a> tag.

See Also:

Constant Field Values

EMAIL_REGEXP

public static final Pattern EMAIL_REGEXP

This pattern can be used to find email addresses. The pattern will check that an @ symbol is present and that it is preceded with at least one character and followed by at least one subdomain and one topdomain. The pattern will allow any unicode letters, digits, underscore and hyphen in the address. It will not check that the domain or email address actually exists.

URL_REGEXP

public static final Pattern URL_REGEXP

This pattern can be used to find URL:s. It will look for sequences starting with http://, https://, ftp:// or www. followed by at least one subdomain and one topdomain followed by an optional port number and an optional path including query information.

LINEBREAKS_REGEXP

public static final Pattern LINEBREAKS_REGEXP

This pattern can be used to find line breaks. It will match any combination of carrige return and linefeed characters as well as some unicode line separator characters.

TAG_REGEXP

public static final Pattern TAG_REGEXP

This pattern can be used to fins HTML tags. It will match both start and end tags. The entire tag with attributes are put in the $1 group, the tag name in the $2 group and the attributes in $3.

SAFE_TAGS

public static final Pattern SAFE_TAGS

This pattern is a list of HTML tags considered "safe".

MARKUP

public static final Pattern MARKUP

Pattern that matches everything inside a HTML tag.

Since:

2.10

LEADING_TRAILING_LINEBREAKS

private static final Pattern LEADING_TRAILING_LINEBREAKS

AT_OR_DOT

private static final Pattern AT_OR_DOT

IMAGE_EXTENSION

private static final Pattern IMAGE_EXTENSION

AMP

private static final Pattern AMP

LT

private static final Pattern LT

GT

private static final Pattern GT

QUOTE

private static final Pattern QUOTE

PERCENT

private static final Pattern PERCENT

PLUS

private static final Pattern PLUS

SPACE

private static final Pattern SPACE

HASH

private static final Pattern HASH

AMPERSAND

private static final Pattern AMPERSAND

BACKSLASH

private static final Pattern BACKSLASH

NEWLINE

private static final Pattern NEWLINE

SINGLE_QUOTE

private static final Pattern SINGLE_QUOTE

DOUBLE_QUOTE

private static final Pattern DOUBLE_QUOTE

Constructor Detail

HTML

public HTML()

Method Detail

isValidEmail

public static boolean isValidEmail(String email)

Checks if the given string looks like an email address. This is done by trying to match it against the EMAIL_REGEXP pattern.

Parameters:

email - The string to check

Returns:

TRUE or FALSE

See Also:

EMAIL_REGEXP

isValidUrl

public static boolean isValidUrl(String url)

Checks if the given string looks like an URL. This is done by trying to match it against the URL_REGEXP pattern.

Parameters:

url - The string to check

Returns:

TRUE or FALSE

See Also:

URL_REGEXP

formatLineBreaks

public static String formatLineBreaks(String in)

Finds all linebreaks in a string and replaces them with a <br> tag, except that leading and trailing linebreaks will be removed.

Parameters:

in - The string to search

Returns:

The new string, or an empty string if NULL was passed

scanForLinks

public static String scanForLinks(String in)

Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags. Using this method is equivalent to: scanForLinks(in, LINK_URL+LINK_EMAIL+SMART_IMAGES, null);

Parameters:

in - The string to search

Returns:

The new string, or an empty string if NULL was passed

scanForLinks

public static String scanForLinks(String in,
                                  int flags)

Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags. Using this method is equivalent to: scanForLinks(in, flags, null);

Parameters:

in - The string to search

flags - A combination of the following flags to indicate what we should search for: LINK_URL, LINK_EMAIL SMART_IMAGES

Returns:

The new string, or an empty string if NULL was passed

scanForLinks

public static String scanForLinks(String in,
                                  String target)

Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags. Using this method is equivalent to: scanForLinks(in, LINK_URL+LINK_EMAIL+SMART_IMAGES, target);

Parameters:

in - The string to search

target - The name of the target window in which the link should be opened

Returns:

The new string, or an empty string if NULL was passed

scanForLinks

public static String scanForLinks(String in,
                                  int flags,
                                  String target)

Scans a string for email addresses and URL:s and replaces them with <a href="---"> tags.

Parameters:

in - The string to search

flags - A combination of the following flags to indicate what we should search for: LINK_URL, LINK_EMAIL SMART_IMAGES

target - The name of the target window in which the link should be opened

Returns:

The new string, or an empty string if NULL was passed

encodeTags

public static String encodeTags(String in)

Scans a string for HTML tags and replaces all & with &amp;, < with &lt;, > with &gt; and all " with "

Parameters:

in - The string to search

Returns:

The new string, or an empty string if NULL was passed

encodeTags

public static String encodeTags(String in,
                                String safeTags)

encodeTags

public static String encodeTags(String in,
                                Pattern safeTags)

urlEncode

public static String urlEncode(String in)

Encode URL-unsafe characters in a string. Replaces % with %25, + with %2B, space with +, # with %23 and & with %26.

Parameters:

in - The string to encode

Returns:

The encoded string, or an empty string if NULL was passed

javaScriptEncode

public static String javaScriptEncode(String in)

Escape a string to make it safe for use in a JavaScript statement. Replaces \ with \\, newline with \n, ' with \' and " with \".

Parameters:

in - String to escape.

Returns:

a String object, ready to be used in javaScripts.

niceFormat

public static String niceFormat(String in)

A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, "_new") and formatLineBreaks(in) in a single operation.

Parameters:

in - The string to format

Returns:

The result after calling the three methods mentioned above, in that order, or an empty string if NULL was passed

niceFormat

public static String niceFormat(String in,
                                int flags)

A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, flags, "_new") and formatLineBreaks(in) in a single operation.

Parameters:

in - The string to format

flags - Flags to be used in the call to scanForLinks

Returns:

The result after calling the three methods mentioned above, in that order, or an empty string if NULL was passed

niceFormat

public static String niceFormat(String in,
                                String linkTarget)

A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, target) and formatLineBreaks(in) in a single operation.

Parameters:

in - The string to format

linkTarget - The target parameter to be used in the call to scanForLinks(String,String)

Returns:

The result after calling the three methods mentioned above, in that order, or an empty string if NULL was passed

niceFormat

public static String niceFormat(String in,
                                int flags,
                                String linkTarget)

A convenience method for doing encodeTags(in, SAFE_TAGS), scanForLinks(in, flags, link_target) and formatLineBreaks(in) in a single operation.

Parameters:

in - The string to format

flags - Flags to be used in the call to scanForLinks

linkTarget - The target parameter to be used in the call to scanForLinks(String,int,String)

Returns:

The result after calling the three methods mentioned above, in that order, or an empty string if NULL was passed

stripMarkup

public static String stripMarkup(CharSequence in)

Remove all HTML markup in a string and return what is left.

Parameters:

in - The string to strip from HTML

Returns:

The resulting string, or null if the input is null

Since:

2.10

textLength

public static int textLength(CharSequence html)

Counts the length of a string ignoring all characters in HTML markup tags. The result is the approximately the length of the string that is displayed on screen by a browser. This method counts all characters that are not inside < and >. The actual number of characters displayed by a browser may be less because of escaped sequences, eg. &amp; and white-space that is collapsed.

Parameters:

html - The HTML string

Returns:

The number of characters that are not HTML markup

Since:

2.10