public class Element extends ParentNode
This class represents an XML element. Each element has the following properties:
Constructor and Description |
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Element(Element element)
Creates a deep copy of an element.
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Element(String name)
Creates a new element in no namespace.
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Element(String name,
String uri)
Creates a new element in a namespace.
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Modifier and Type | Method and Description |
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void | addAttribute(Attribute attribute)
Adds an attribute to this element, replacing any existing
attribute with the same local name and namespace URI.
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void | addNamespaceDeclaration(String prefix,
String uri)
Declares a namespace prefix.
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void | appendChild(String text)
Converts a string to a text node
and appends that node to the children of this node.
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Element | copy()
Creates a deep copy of this element with no parent,
that can be added to this document or a different one.
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Attribute | getAttribute(int index)
Selects an attribute by index.
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Attribute | getAttribute(String name)
Returns the attribute with the specified name in no namespace,
or null if this element does not have an attribute
with that name in no namespace.
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Attribute | getAttribute(String localName,
String namespaceURI)
Returns the attribute with the specified name and namespace URI,
or null if this element does not have an attribute
with that name in that namespace.
|
int | getAttributeCount()
Returns the number of attributes of this
Element ,
not counting namespace declarations. |
String | getAttributeValue(String name)
Returns the value of the attribute with the specified
name in no namespace,
or null if this element does not have an attribute
with that name.
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String | getAttributeValue(String localName,
String namespaceURI)
Returns the value of the attribute with the
specified name and namespace URI,
or null if this element does not have such an attribute.
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String | getBaseURI()
Returns the absolute base URI against which relative URIs in
this element should be resolved.
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Elements | getChildElements()
Returns a list of all the child elements
of this element in document order.
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Elements | getChildElements(String name)
Returns a list of the child elements of
this element with the specified name in no namespace.
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Elements | getChildElements(String localName,
String namespaceURI)
Returns a list of the immediate child elements of this
element with the specified local name and namespace URI.
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Element | getFirstChildElement(String name)
Returns the first child
element with the specified name in no namespace.
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Element | getFirstChildElement(String localName,
String namespaceURI)
Returns the first child
element with the specified local name and namespace URI.
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String | getLocalName()
Returns the local name of this element, not including the
namespace prefix or colon.
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int | getNamespaceDeclarationCount()
Returns the number of namespace declarations on this
element.
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String | getNamespacePrefix()
Returns the prefix of this element, or the empty string
if this element does not have a prefix.
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String | getNamespacePrefix(int index)
Returns the indexth namespace prefix declared on
this element.
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String | getNamespaceURI()
Returns the namespace URI of this element,
or the empty string if this element is not
in a namespace.
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String | getNamespaceURI(String prefix)
Returns the namespace URI mapped to the specified
prefix within this element.
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String | getQualifiedName()
Returns the complete name of this element, including the
namespace prefix if this element has one.
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String | getValue()
Returns the value of the element as defined by XPath 1.0.
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void | insertChild(String text,
int position)
Converts a string to a text node and inserts that
node at the specified position.
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Attribute | removeAttribute(Attribute attribute)
Removes an attribute from this element.
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Nodes | removeChildren()
Detaches all children from this node.
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void | removeNamespaceDeclaration(String prefix)
Removes the mapping of the specified prefix.
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void | setBaseURI(String URI)
Sets the URI from which this element was loaded,
and against which relative URLs in this element will be
resolved, unless an
xml:base attribute overrides
this. |
void | setLocalName(String localName)
Sets the local name of this element.
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void | setNamespacePrefix(String prefix)
Sets the namespace prefix of this element.
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void | setNamespaceURI(String uri)
Sets the namespace URI of this element.
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protected Element | shallowCopy()
Creates a very shallow copy of the element with the same name
and namespace URI, but no children, attributes, base URI, or
namespace declaration.
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String | toString()
Returns a string representation of this element suitable
for debugging and diagnosis.
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String | toXML()
Returns a string containing the XML serialization of this
element.
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appendChild, getChild, getChildCount, indexOf, insertChild, removeChild, removeChild, replaceChild
public Element(String name)
Creates a new element in no namespace.
name
- the name of the elementIllegalNameException
- if name
is not a legal XML 1.0 non-colonized namepublic Element(String name, String uri)
Creates a new element in a namespace.
name
- the qualified name of the elementuri
- the namespace URI of the elementIllegalNameException
- if name
is not a legal XML 1.0 nameNamespaceConflictException
- if name
's prefix
cannot be used with uri
MalformedURIException
- if uri
is not an RFC 3986 absolute URI referencepublic Element(Element element)
Creates a deep copy of an element. The copy is disconnected from the tree, and does not have a parent.
element
- the element to copypublic final Elements getChildElements(String name)
Returns a list of the child elements of this element with the specified name in no namespace. The elements returned are in document order.
name
- the name of the elements included in the listpublic final Elements getChildElements(String localName, String namespaceURI)
Returns a list of the immediate child elements of this element with the specified local name and namespace URI. Passing the empty string or null as the local name returns all elements in the specified namespace. Passing null or the empty string as the namespace URI returns elements with the specified name in no namespace. The elements returned are in document order.
localName
- the name of the elements included in the listnamespaceURI
- the namespace URI of the elements included
in the listpublic final Elements getChildElements()
Returns a list of all the child elements of this element in document order.
public final Element getFirstChildElement(String name)
Returns the first child element with the specified name in no namespace. If there is no such element, it returns null.
name
- the name of the element to returnpublic final Element getFirstChildElement(String localName, String namespaceURI)
Returns the first child element with the specified local name and namespace URI. If there is no such element, it returns null.
localName
- the local name of the element to returnnamespaceURI
- the namespace URI of the element to returnpublic void addAttribute(Attribute attribute)
Adds an attribute to this element, replacing any existing attribute with the same local name and namespace URI.
attribute
- the attribute to addMultipleParentException
- if the attribute is already
attached to an elementNamespaceConflictException
- if the attribute's prefix
is mapped to a different namespace URI than the same prefix
is mapped to by this element, another attribute of
this element, or an additional namespace declaration
of this elementpublic Attribute removeAttribute(Attribute attribute)
Removes an attribute from this element.
attribute
- the attribute to removeNoSuchAttributeException
- if this element is not the
parent of attributepublic final Attribute getAttribute(String name)
Returns the attribute with the specified name in no namespace, or null if this element does not have an attribute with that name in no namespace.
name
- the name of the attributepublic final Attribute getAttribute(String localName, String namespaceURI)
Returns the attribute with the specified name and namespace URI, or null if this element does not have an attribute with that name in that namespace.
localName
- the local name of the attributenamespaceURI
- the namespace of the attributepublic final String getAttributeValue(String name)
Returns the value of the attribute with the specified name in no namespace, or null if this element does not have an attribute with that name.
name
- the name of the attributepublic final int getAttributeCount()
Returns the number of attributes of this Element
,
not counting namespace declarations.
This is always a non-negative number.
public final Attribute getAttribute(int index)
Selects an attribute by index.
The index is purely for convenience and has no particular
meaning. In particular, it is not necessarily the
position of this attribute in the original document from
which this Element
object was read.
As with most lists in Java, attributes are numbered
from 0 to one less than the length of the list.
In general, you should not add attributes to or remove
attributes from the list while iterating across it.
Doing so will change the indexes of the other attributes in
the list. it is, however, safe to remove an attribute from
either end of the list (0 or getAttributeCount()-1
)
until there are no attributes left.
index
- the attribute to returnIndexOutofBoundsException
- if the index is negative
or greater than or equal to the number of attributes
of this elementpublic final String getAttributeValue(String localName, String namespaceURI)
Returns the value of the attribute with the specified name and namespace URI, or null if this element does not have such an attribute.
localName
- the name of the attributenamespaceURI
- the namespace of the attributepublic final String getLocalName()
Returns the local name of this element, not including the namespace prefix or colon.
public final String getQualifiedName()
Returns the complete name of this element, including the namespace prefix if this element has one.
public final String getNamespacePrefix()
Returns the prefix of this element, or the empty string if this element does not have a prefix.
public final String getNamespaceURI()
Returns the namespace URI of this element, or the empty string if this element is not in a namespace.
public final String getNamespaceURI(String prefix)
Returns the namespace URI mapped to the specified prefix within this element. Returns null if this prefix is not associated with a URI.
prefix
- the namespace prefix whose URI is desiredprefix
public void setLocalName(String localName)
Sets the local name of this element.
localName
- the new local nameIllegalNameException
- if localName
is not
a legal, non-colonized namepublic void setNamespaceURI(String uri)
Sets the namespace URI of this element.
uri
- the new namespace URIMalformedURIException
- if uri
is not an absolute RFC 3986 URI referenceNamespaceException
- if this element has a prefix
and uri
is null or the empty string;
or if the element's prefix is shared by an attribute
or additional namespacepublic void setNamespacePrefix(String prefix)
Sets the namespace prefix of this element. You can pass null or the empty string to remove the prefix.
prefix
- the new namespace prefixIllegalNameException
- if prefix
is
not a legal XML non-colonized nameNamespaceConflictException
- if prefix
is
already in use by an attribute or additional
namespace with a different URI than the element
itselfpublic void insertChild(String text, int position)
Converts a string to a text node and inserts that node at the specified position.
position
- where to insert the childtext
- the string to convert to a text node and insertNullPointerException
- if text is nullIndexOutOfBoundsException
- if the position is negative
or greater than the number of children of the nodepublic void appendChild(String text)
Converts a string to a text node and appends that node to the children of this node.
text
- String to add to this nodeIllegalAddException
- if this node cannot
have children of this typeNullPointerException
- if text
is nullpublic Nodes removeChildren()
Detaches all children from this node.
Subclassers should note that the default implementation of this
method does not call removeChild
or detach
. If you override
removeChild
, you'll probably need to override this
method as well.
public void addNamespaceDeclaration(String prefix, String uri)
Declares a namespace prefix. This is only necessary when prefixes are used in element content and attribute values, as in XSLT and the W3C XML Schema Language. Do not use this method to declare prefixes for element and attribute names.
You can supply an empty string for the prefix to declare a default namespace, provided the element itself has a prefix.
If you do redeclare a prefix that is already used by an element or attribute name, the additional namespace is added if and only if the URI is the same. Conflicting namespace declarations will throw an exception.
prefix
- the prefix to declareuri
- the absolute URI reference to map the prefix toMalformedURIException
- if URI
is not an RFC 3986 URI referenceIllegalNameException
- if prefix
is not
a legal XML non-colonized name or the empty stringNamespaceConflictException
- if the mapping conflicts
with an existing element, attribute,
or additional namespace declarationpublic void removeNamespaceDeclaration(String prefix)
Removes the mapping of the specified prefix. This method only
removes additional namespaces added with
addNamespaceDeclaration
.
It has no effect on namespaces of elements and attributes.
If the prefix is not used on this element, this method
does nothing.
prefix
- the prefix whose declaration should be removedpublic final int getNamespaceDeclarationCount()
Returns the number of namespace declarations on this
element. This counts the namespace of the element
itself (which may be the empty string), the namespace
of each attribute, and each namespace added
by addNamespaceDeclaration
.
However, prefixes used multiple times are only counted
once; and the xml
prefix used for
xml:base
, xml:lang
, and
xml:space
is not counted even if one of these
attributes is present on the element.
The return value is almost always positive. It can be zero
if and only if the element itself has the prefix
xml
; e.g. <xml:space />
.
This is not endorsed by the XML specification. The prefix
xml
is reserved for use by the W3C, which has only
used it for attributes to date. You really shouldn't do this.
Nonetheless, this is not malformed so XOM allows it.
public final String getNamespacePrefix(int index)
Returns the indexth namespace prefix declared on
this element. Namespaces inherited from ancestors are not included.
The index is purely for convenience, and has no
meaning in itself. This includes the namespaces of the element
name and of all attributes' names (except for those with the
prefix xml
such as xml:space
) as well
as additional declarations made for attribute values and element
content. However, prefixes used multiple times (e.g. on several
attribute values) are only reported once. The default
namespace is reported with an empty string prefix if present.
Like most lists in Java, the first prefix is at index 0.
If the namespaces on the element change for any reason (adding or removing an attribute in a namespace, adding or removing a namespace declaration, changing the prefix of an element, etc.) then this method may skip or repeat prefixes. Don't change the prefixes of an element while iterating across them.
index
- the prefix to returnIndexOutOfBoundsException
- if index
is
negative or greater than or equal to the number of
namespaces declared by this element.public void setBaseURI(String URI)
Sets the URI from which this element was loaded,
and against which relative URLs in this element will be
resolved, unless an xml:base
attribute overrides
this. Setting the base URI to null or the empty string removes
any existing base URI.
setBaseURI
in class ParentNode
URI
- the new base URI for this elementMalformedURIException
- if URI
is
not a legal RFC 3986 absolute URIpublic String getBaseURI()
Returns the absolute base URI against which relative URIs in
this element should be resolved. xml:base
attributes in the same entity take precedence over the
actual base URI of the document where the element was found
or which was set by setBaseURI
.
This URI is made absolute before it is returned by resolving the information in this element against the information in its parent element and document entity. However, it is not always possible to fully absolutize the URI in all circumstances. In this case, this method returns the empty string to indicate the base URI of the current entity.
If the element's xml:base
attribute contains a
value that is a syntactically illegal URI (e.g. %GF.html"),
then the base URI is application dependent. XOM's choice is
to behave as if the element did not have an xml:base
attribute.
getBaseURI
in class Node
public final String toXML()
Returns a string containing the XML serialization of this element. This includes the element and all its attributes and descendants. However, it does not contain namespace declarations for namespaces inherited from ancestor elements.
public final String getValue()
Returns the value of the element as defined by XPath 1.0. This is the complete PCDATA content of the element, without any tags, comments, or processing instructions after all entity and character references have been resolved.
public Element copy()
Creates a deep copy of this element with no parent, that can be added to this document or a different one.
Subclassers should be wary. Implementing this method is trickier
than it might seem, especially if you wish to avoid potential
stack overflows in deep documents. In particular, you should not
rely on the obvious recursive algorithm. Most subclasses should
override the shallowCopy
method instead.
protected Element shallowCopy()
Creates a very shallow copy of the element with the same name
and namespace URI, but no children, attributes, base URI, or
namespace declaration. This method is invoked as necessary
by the copy
method
and the copy constructor
.
Subclasses should override this method so that it returns an instance of the subclass so that types are preserved when copying. This method should not add any attributes, namespace declarations, or children to the shallow copy. Any such items will be overwritten.
public String toString()
Returns a string representation of this element suitable for debugging and diagnosis. This is not the XML representation of the element.
toString
in class Object
Copyright 2002-2023 Elliotte Rusty Harold
elharo@ibiblio.org