Class AttrImpl
- All Implemented Interfaces:
Serializable
,Cloneable
,Attr
,EventTarget
,Node
,NodeList
,TypeInfo
- Direct Known Subclasses:
AttrNSImpl
,DeferredAttrImpl
If the attribute has not been explicitly assigned a value, but has been declared in the DTD, it will exist and have that default. Only if neither the document nor the DTD specifies a value will the Attribute really be considered absent and have no value; in that case, querying the attribute will return null.
Attributes may have multiple children that contain their data. (XML allows attributes to contain entity references, and tokenized attribute types such as NMTOKENS may have a child for each token.) For convenience, the Attribute object's getValue() method returns the string version of the attribute's value.
Attributes are not children of the Elements they belong to, in the usual sense, and have no valid Parent reference. However, the spec says they _do_ belong to a specific Element, and an INUSE exception is to be thrown if the user attempts to explicitly share them between elements.
Note that Elements do not permit attributes to appear to be shared (see the INUSE exception), so this object's mutability is officially not an issue.
Note: The ownerNode attribute is used to store the Element the Attr node is associated with. Attr nodes do not have parent nodes. Besides, the getOwnerElement() method can be used to get the element node this attribute is associated with.
AttrImpl does not support Namespaces. AttrNSImpl, which inherits from it, does.
AttrImpl used to inherit from ParentNode. It now directly inherits from NodeImpl and provide its own implementation of the ParentNode's behavior. The reason is that we now try and avoid to always create a Text node to hold the value of an attribute. The DOM spec requires it, so we still have to do it in case getFirstChild() is called for instance. The reason attribute values are stored as a list of nodes is so that they can carry more than a simple string. They can also contain EntityReference nodes. However, most of the times people only have a single string that they only set and get through Element.set/getAttribute or Attr.set/getValue. In this new version, the Attr node has a value pointer which can either be the String directly or a pointer to the first ChildNode. A flag tells which one it currently is. Note that while we try to stick with the direct String as much as possible once we've switched to a node there is no going back. This is because we have no way to know whether the application keeps referring to the node we once returned.
The gain in memory varies on the density of attributes in the document. But in the tests I've run I've seen up to 12% of memory gain. And the good thing is that it also leads to a slight gain in speed because we allocate fewer objects! I mean, that's until we have to actually create the node...
To avoid too much duplicated code, I got rid of ParentNode and renamed ChildAndParentNode, which I never really liked, to ParentNode for simplicity, this doesn't make much of a difference in memory usage because there are only very few objects that are only a Parent. This is only true now because AttrImpl now inherits directly from NodeImpl and has its own implementation of the ParentNode's node behavior. So there is still some duplicated code there.
This class doesn't directly support mutation events, however, it notifies the document when mutations are performed so that the document class do so.
WARNING: Some of the code here is partially duplicated in ParentNode, be careful to keep these two classes in sync!
INTERNAL:
- Usage of this class is not supported. It may be altered or removed at any time.
- Since:
- PR-DOM-Level-1-19980818.
- Version:
- $Id: AttrImpl.java 924245 2010-03-17 11:58:14Z mrglavas $
- Author:
- Arnaud Le Hors, IBM, Joe Kesselman, IBM, Andy Clark, IBM
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected String
Attribute name.protected Object
This can either be a String or the first child node.Fields inherited from class org.apache.xerces.dom.NodeImpl
DOCUMENT_POSITION_CONTAINS, DOCUMENT_POSITION_DISCONNECTED, DOCUMENT_POSITION_FOLLOWING, DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC, DOCUMENT_POSITION_IS_CONTAINED, DOCUMENT_POSITION_PRECEDING, ELEMENT_DEFINITION_NODE, FIRSTCHILD, flags, HASSTRING, ID, IGNORABLEWS, NORMALIZED, OWNED, ownerNode, READONLY, SPECIFIED, SYNCCHILDREN, SYNCDATA, TREE_POSITION_ANCESTOR, TREE_POSITION_DESCENDANT, TREE_POSITION_DISCONNECTED, TREE_POSITION_EQUIVALENT, TREE_POSITION_FOLLOWING, TREE_POSITION_PRECEDING, TREE_POSITION_SAME_NODE
Fields inherited from interface org.w3c.dom.Node
ATTRIBUTE_NODE, CDATA_SECTION_NODE, COMMENT_NODE, DOCUMENT_FRAGMENT_NODE, DOCUMENT_NODE, DOCUMENT_POSITION_CONTAINED_BY, DOCUMENT_POSITION_CONTAINS, DOCUMENT_POSITION_DISCONNECTED, DOCUMENT_POSITION_FOLLOWING, DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC, DOCUMENT_POSITION_PRECEDING, DOCUMENT_TYPE_NODE, ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, NOTATION_NODE, PROCESSING_INSTRUCTION_NODE, TEXT_NODE
Fields inherited from interface org.w3c.dom.TypeInfo
DERIVATION_EXTENSION, DERIVATION_LIST, DERIVATION_RESTRICTION, DERIVATION_UNION
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
AttrImpl()
protected
AttrImpl
(CoreDocumentImpl ownerDocument, String name) Attribute has no public constructor. -
Method Summary
Modifier and TypeMethodDescriptioncloneNode
(boolean deep) Returns a duplicate of a given node.Obtain a NodeList enumerating all children of this node.Deprecated.Previous working draft of DOM Level 2.The first child of this Node, or null if none.The last child of this Node, or null if none.int
NodeList method: Count the immediate children of this nodegetName()
In Attributes, NodeName is considered a synonym for the attribute's NameReturns the attribute nameshort
A short integer indicating what type of node this is.In Attribute objects, NodeValue is considered a synonym for Value.Returns the element node that this attribute is associated with, or null if the attribute has not been added to an element.Method getSchemaTypeInfo.boolean
The "specified" flag is true if and only if this attribute's value was explicitly specified in the original document.getValue()
The "string value" of an Attribute is its text representation, which in turn is a concatenation of the string values of its children.boolean
Test whether this node has any children.insertBefore
(Node newChild, Node refChild) Move one or more node(s) to our list of children.boolean
isDerivedFrom
(String typeNamespaceArg, String typeNameArg, int derivationMethod) Introduced in DOM Level 3.boolean
isEqualNode
(Node arg) DOM Level 3 WD- Experimental.boolean
isId()
DOM Level 3: isIditem
(int index) NodeList method: Return the Nth immediate child of this node, or null if the index is out of bounds.protected void
void
Puts allText
nodes in the full depth of the sub-tree underneath thisNode
, including attribute nodes, into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separatesText
nodes, i.e., there are no adjacentText
nodes.removeChild
(Node oldChild) Remove a child from this Node.replaceChild
(Node newChild, Node oldChild) Make newChild occupy the location that oldChild used to have.void
setIdAttribute
(boolean id) NON-DOM: set the type of this attribute to be ID type.void
setNodeValue
(String value) Implicit in the rerouting of getNodeValue to getValue is the need to redefine setNodeValue, for symmetry's sake.protected void
NON-DOM set the ownerDocument of this node and its childrenvoid
setReadOnly
(boolean readOnly, boolean deep) Override default behavior so that if deep is true, children are also toggled.void
setSpecified
(boolean arg) NON-DOM, for use by parservoid
NON-DOM: used by the parservoid
The DOM doesn't clearly define what setValue(null) means.protected void
Override this method in subclass to hook in efficient internal data structure.toString()
NON-DOM method for debugging convenienceMethods inherited from class org.apache.xerces.dom.NodeImpl
addEventListener, appendChild, changed, changes, compareDocumentPosition, compareTreePosition, dispatchEvent, getAttributes, getBaseURI, getContainer, getFeature, getLocalName, getNamespaceURI, getNextSibling, getNodeNumber, getOwnerDocument, getParentNode, getPrefix, getPreviousSibling, getReadOnly, getTextContent, getUserData, getUserData, getUserDataRecord, hasAttributes, isDefaultNamespace, isSameNode, isSupported, lookupNamespaceURI, lookupPrefix, needsSyncChildren, removeEventListener, setPrefix, setTextContent, setUserData, setUserData, synchronizeData
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.w3c.dom.Node
appendChild, compareDocumentPosition, getAttributes, getBaseURI, getFeature, getLocalName, getNamespaceURI, getNextSibling, getOwnerDocument, getParentNode, getPrefix, getPreviousSibling, getTextContent, getUserData, hasAttributes, isDefaultNamespace, isSameNode, isSupported, lookupNamespaceURI, lookupPrefix, setPrefix, setTextContent, setUserData
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Field Details
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value
This can either be a String or the first child node. -
name
Attribute name.
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Constructor Details
-
AttrImpl
Attribute has no public constructor. Please use the factory method in the Document class. -
AttrImpl
protected AttrImpl()
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Method Details
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makeChildNode
protected void makeChildNode() -
setOwnerDocument
NON-DOM set the ownerDocument of this node and its children- Overrides:
setOwnerDocument
in classNodeImpl
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setIdAttribute
public void setIdAttribute(boolean id) NON-DOM: set the type of this attribute to be ID type.- Parameters:
id
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isId
public boolean isId()DOM Level 3: isId -
cloneNode
Description copied from class:NodeImpl
Returns a duplicate of a given node. You can consider this a generic "copy constructor" for nodes. The newly returned object should be completely independent of the source object's subtree, so changes in one after the clone has been made will not affect the other.Note: since we never have any children deep is meaningless here, ParentNode overrides this behavior.
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getNodeType
public short getNodeType()A short integer indicating what type of node this is. The named constants for this value are defined in the org.w3c.dom.Node interface.- Specified by:
getNodeType
in interfaceNode
- Specified by:
getNodeType
in classNodeImpl
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getNodeName
Returns the attribute name- Specified by:
getNodeName
in interfaceNode
- Specified by:
getNodeName
in classNodeImpl
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setNodeValue
Implicit in the rerouting of getNodeValue to getValue is the need to redefine setNodeValue, for symmetry's sake. Note that since we're explicitly providing a value, Specified should be set true.... even if that value equals the default.- Specified by:
setNodeValue
in interfaceNode
- Overrides:
setNodeValue
in classNodeImpl
- Throws:
DOMException
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getTypeName
- Specified by:
getTypeName
in interfaceTypeInfo
- See Also:
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getTypeNamespace
- Specified by:
getTypeNamespace
in interfaceTypeInfo
- See Also:
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getSchemaTypeInfo
Method getSchemaTypeInfo.- Specified by:
getSchemaTypeInfo
in interfaceAttr
- Returns:
- TypeInfo
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getNodeValue
In Attribute objects, NodeValue is considered a synonym for Value.- Specified by:
getNodeValue
in interfaceNode
- Overrides:
getNodeValue
in classNodeImpl
- See Also:
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getName
In Attributes, NodeName is considered a synonym for the attribute's Name -
setValue
The DOM doesn't clearly define what setValue(null) means. I've taken it as "remove all children", which from outside should appear similar to setting it to the empty string. -
getValue
The "string value" of an Attribute is its text representation, which in turn is a concatenation of the string values of its children. -
getSpecified
public boolean getSpecified()The "specified" flag is true if and only if this attribute's value was explicitly specified in the original document. Note that the implementation, not the user, is in charge of this property. If the user asserts an Attribute value (even if it ends up having the same value as the default), it is considered a specified attribute. If you really want to revert to the default, delete the attribute from the Element, and the Implementation will re-assert the default (if any) in its place, with the appropriate specified=false setting.- Specified by:
getSpecified
in interfaceAttr
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getElement
Deprecated.Previous working draft of DOM Level 2. New method is getOwnerElement().Returns the element node that this attribute is associated with, or null if the attribute has not been added to an element.- See Also:
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getOwnerElement
Returns the element node that this attribute is associated with, or null if the attribute has not been added to an element.- Specified by:
getOwnerElement
in interfaceAttr
- Since:
- WD-DOM-Level-2-19990719
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normalize
public void normalize()Description copied from class:NodeImpl
Puts allText
nodes in the full depth of the sub-tree underneath thisNode
, including attribute nodes, into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separatesText
nodes, i.e., there are no adjacentText
nodes. This can be used to ensure that the DOM view of a document is the same as if it were saved and re-loaded, and is useful when operations (such as XPointer lookups) that depend on a particular document tree structure are to be used.In cases where the document containsCDATASections
, the normalize operation alone may not be sufficient, since XPointers do not differentiate betweenText
nodes andCDATASection
nodes.Note that this implementation simply calls normalize() on this Node's children. It is up to implementors or Node to override normalize() to take action.
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setSpecified
public void setSpecified(boolean arg) NON-DOM, for use by parser -
setType
NON-DOM: used by the parser- Parameters:
type
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toString
NON-DOM method for debugging convenience -
hasChildNodes
public boolean hasChildNodes()Test whether this node has any children. Convenience shorthand for (Node.getFirstChild()!=null)- Specified by:
hasChildNodes
in interfaceNode
- Overrides:
hasChildNodes
in classNodeImpl
- See Also:
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getChildNodes
Obtain a NodeList enumerating all children of this node. If there are none, an (initially) empty NodeList is returned.NodeLists are "live"; as children are added/removed the NodeList will immediately reflect those changes. Also, the NodeList refers to the actual nodes, so changes to those nodes made via the DOM tree will be reflected in the NodeList and vice versa.
In this implementation, Nodes implement the NodeList interface and provide their own getChildNodes() support. Other DOMs may solve this differently.
- Specified by:
getChildNodes
in interfaceNode
- Overrides:
getChildNodes
in classNodeImpl
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getFirstChild
The first child of this Node, or null if none.- Specified by:
getFirstChild
in interfaceNode
- Overrides:
getFirstChild
in classNodeImpl
- See Also:
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getLastChild
The last child of this Node, or null if none.- Specified by:
getLastChild
in interfaceNode
- Overrides:
getLastChild
in classNodeImpl
- See Also:
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insertBefore
Move one or more node(s) to our list of children. Note that this implicitly removes them from their previous parent.- Specified by:
insertBefore
in interfaceNode
- Overrides:
insertBefore
in classNodeImpl
- Parameters:
newChild
- The Node to be moved to our subtree. As a convenience feature, inserting a DocumentNode will instead insert all its children.refChild
- Current child which newChild should be placed immediately before. If refChild is null, the insertion occurs after all existing Nodes, like appendChild().- Returns:
- newChild, in its new state (relocated, or emptied in the case of DocumentNode.)
- Throws:
DOMException
- See Also:
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removeChild
Remove a child from this Node. The removed child's subtree remains intact so it may be re-inserted elsewhere.- Specified by:
removeChild
in interfaceNode
- Overrides:
removeChild
in classNodeImpl
- Returns:
- oldChild, in its new state (removed).
- Throws:
DOMException
- See Also:
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replaceChild
Make newChild occupy the location that oldChild used to have. Note that newChild will first be removed from its previous parent, if any. Equivalent to inserting newChild before oldChild, then removing oldChild.- Specified by:
replaceChild
in interfaceNode
- Overrides:
replaceChild
in classNodeImpl
- Returns:
- oldChild, in its new state (removed).
- Throws:
DOMException
- See Also:
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getLength
public int getLength()NodeList method: Count the immediate children of this node -
item
NodeList method: Return the Nth immediate child of this node, or null if the index is out of bounds. -
isEqualNode
DOM Level 3 WD- Experimental. Override inherited behavior from ParentNode to support deep equal. isEqualNode is always deep on Attr nodes.- Specified by:
isEqualNode
in interfaceNode
- Overrides:
isEqualNode
in classNodeImpl
- Parameters:
arg
- The node to compare equality with.- Returns:
- If the nodes, and possibly subtrees are equal,
true
otherwisefalse
.
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isDerivedFrom
Introduced in DOM Level 3.Checks if a type is derived from another by restriction. See: http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-isDerivedFrom
- Specified by:
isDerivedFrom
in interfaceTypeInfo
- Parameters:
typeNamespaceArg
- The namspace of the ancestor type declarationtypeNameArg
- The name of the ancestor type declarationderivationMethod
- The derivation method- Returns:
- boolean True if the type is derived by restriciton for the reference type
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setReadOnly
public void setReadOnly(boolean readOnly, boolean deep) Override default behavior so that if deep is true, children are also toggled.- Overrides:
setReadOnly
in classNodeImpl
- Parameters:
readOnly
- True or false as desired.deep
- If true, children are also toggled. Note that this will not change the state of an EntityReference or its children, which are always read-only.- See Also:
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synchronizeChildren
protected void synchronizeChildren()Override this method in subclass to hook in efficient internal data structure.
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