de.gerdiproject.harvest.utils

Class HtmlUtils

java.lang.Object

de.gerdiproject.harvest.utils.HtmlUtils

public class HtmlUtils
extends Object

A collection of static methods for processing HTML Elements.

Author:

Robin Weiss

Method Summary

Modifier and Type	Method and Description
static <T> List<T>	elementsToList(Collection<org.jsoup.nodes.Element> elements, Function<org.jsoup.nodes.Element,T> eleToObject) Applies a specified mapping function to every Element of a Collection, to generate a List of mapped objects.
static List<String>	elementsToStringList(Collection<org.jsoup.nodes.Element> elements) Maps a Collection of Elements to a List of Strings by retrieving the text of the Elements.
static String	getAttribute(org.jsoup.nodes.Element element, String attributeKey) Retrieves an attribute value of an HTML Element.
static <T extends Enum<T>> T	getEnumAttribute(org.jsoup.nodes.Element element, String attributeKey, Class<T> enumClass) Retrieves an attribute value of an HTML Element and attempts to map it to an Enum.
static <T> T	getObject(org.jsoup.nodes.Element element, String tagName, Function<org.jsoup.nodes.Element,T> eleToObject) Retrieves the first occurrence of an Element with a specified tag and maps it to an object via a specified mapping function.
static <T> List<T>	getObjects(org.jsoup.nodes.Element element, String tagName, Function<org.jsoup.nodes.Element,T> eleToObject) Retrieves all occurrences of Elements with specified tags and maps them to a List of objects via a specified mapping function.
static <T> List<T>	getObjectsFromParent(org.jsoup.nodes.Element element, String parentTagName, Function<org.jsoup.nodes.Element,T> eleToObject) Retrieves all child Elements of a specified parent tag and maps them to a List of objects via a specified mapping function.
static String	getString(org.jsoup.nodes.Element element, String tagName) Retrieves the text of the first occurrence of a specified tag derived from a specified Element.
static List<String>	getStrings(org.jsoup.nodes.Element element, String tagName) Retrieves the texts of all occurrences of Elements with a specified tag name.
static List<String>	getStringsFromParent(org.jsoup.nodes.Element element, String parentTagName) Retrieves the texts of all children of a specified parent Element.

Methods inherited from class java.lang.Object

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

Method Detail

getString

public static String getString(org.jsoup.nodes.Element element,
                               String tagName)

Retrieves the text of the first occurrence of a specified tag derived from a specified Element.

Parameters:

element - the HTML Element that contains the tag

tagName - the name of the tag of which the text is to be retrieved

Returns:

the text inside the first occurrence of a specified tag, or null if the tag could not be found

getStringsFromParent

public static List<String> getStringsFromParent(org.jsoup.nodes.Element element,
                                                String parentTagName)

Retrieves the texts of all children of a specified parent Element.

Parameters:

element - the HTML Element that contains the parent tag

parentTagName - the name of the parent Element of the child tags

Returns:

a List of Strings or null if the tag could not be found

getStrings

public static List<String> getStrings(org.jsoup.nodes.Element element,
                                      String tagName)

Retrieves the texts of all occurrences of Elements with a specified tag name.

Parameters:

element - the HTML Element that contains the elements

tagName - the tag name of the Elements to be retrieved

Returns:

a List of Strings or null if no tag could not be found

getObject

public static <T> T getObject(org.jsoup.nodes.Element element,
                              String tagName,
                              Function<org.jsoup.nodes.Element,T> eleToObject)

Retrieves the first occurrence of an Element with a specified tag and maps it to an object via a specified mapping function.

Type Parameters:

T - the output type of the mapping function

Parameters:

element - the HTML Element that contains the requested tag

tagName - the name of the requested tag

eleToObject - a function that maps the found Element to T

Returns:

an object representation of the tag or null if it does not exist

getObjects

public static <T> List<T> getObjects(org.jsoup.nodes.Element element,
                                     String tagName,
                                     Function<org.jsoup.nodes.Element,T> eleToObject)

Retrieves all occurrences of Elements with specified tags and maps them to a List of objects via a specified mapping function.

Type Parameters:

T - the output type of the mapping function

Parameters:

element - the HTML Element that contains the requested tags

tagName - the name of the requested tag

eleToObject - a function that maps the found Elements to T

Returns:

a List of object representations of the tag, or null if no matching tags were found

getObjectsFromParent

public static <T> List<T> getObjectsFromParent(org.jsoup.nodes.Element element,
                                               String parentTagName,
                                               Function<org.jsoup.nodes.Element,T> eleToObject)

Retrieves all child Elements of a specified parent tag and maps them to a List of objects via a specified mapping function.

Type Parameters:

T - the output type of the mapping function

Parameters:

element - the HTML Element that contains the parent tag

parentTagName - the name of the parent tag

eleToObject - a function that maps the child Elements to T

Returns:

a List of objects of the tag or null if it does not exist

getAttribute

public static String getAttribute(org.jsoup.nodes.Element element,
                                  String attributeKey)

Retrieves an attribute value of an HTML Element.

Parameters:

element - the HTML Element from which the attribute is retrieved

attributeKey - the key of the attribute

Returns:

the attribute value, or null if no such attribute exists

getEnumAttribute

public static <T extends Enum<T>> T getEnumAttribute(org.jsoup.nodes.Element element,
                                                     String attributeKey,
                                                     Class<T> enumClass)

Retrieves an attribute value of an HTML Element and attempts to map it to an Enum.

Type Parameters:

T - the type of the Enum

Parameters:

element - the HTML Element from which the attribute is retrieved

attributeKey - the key of the attribute

enumClass - the Enum class to which the attribute value must be mapped

Returns:

the enum representation of the attribute value, or null if the attribute is missing or could not be mapped

elementsToList

public static <T> List<T> elementsToList(Collection<org.jsoup.nodes.Element> elements,
                                         Function<org.jsoup.nodes.Element,T> eleToObject)

Applies a specified mapping function to every Element of a Collection, to generate a List of mapped objects.

Type Parameters:

T - the output type of the mapping function

Parameters:

elements - the Element that are to be mapped to objects

eleToObject - a function that maps the Elements to T

Returns:

a LinkedList of objects that were mapped or null if no object could be mapped

elementsToStringList

public static List<String> elementsToStringList(Collection<org.jsoup.nodes.Element> elements)

Maps a Collection of Elements to a List of Strings by retrieving the text of the Elements.

Parameters:

elements - the Elements that are to be converted to Strings

Returns:

a LinkedList of Strings