Package org.simpleframework.xml.core
Class EmptyExpression
java.lang.Object
org.simpleframework.xml.core.EmptyExpression
- All Implemented Interfaces:
Iterable<String>
,Expression
The
EmptyExpression
object is used to represent a path
that represents the current context. This is a much more lightweight
alternative to parsing "." with the PathParser
object
as it does not require the allocation of collections or buffers.- See Also:
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiongetAttribute
(String name) This is used to acquire the attribute path using this XPath expression.getElement
(String name) This is used to acquire the element path using this XPath expression.getFirst()
This can be used to acquire the first path segment within the expression.int
getIndex()
If the first path segment contains an index it is provided by this method.getLast()
This can be used to acquire the last path segment within the expression.getPath()
This location contains the full path expression with all of the indexes explicitly shown for each path segment.getPath
(int from) This allows an expression to be extracted from the current context.getPath
(int from, int trim) This allows an expression to be extracted from the current context.This is used to extract a namespace prefix from the path expression.boolean
This is used to determine if the expression points to an attribute value.boolean
isEmpty()
This method is used to determine if this expression is an empty path.boolean
isPath()
This is used to determine if the expression is a path.iterator()
This is used to iterate over the path segments that have been extracted from the source XPath expression.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.simpleframework.xml.core.Expression
toString
Methods inherited from interface java.lang.Iterable
forEach, spliterator
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Field Details
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list
This is a list that is used to create an empty iterator. -
style
This is the style that is used to style any paths created.
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Constructor Details
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EmptyExpression
Constructor forEmptyExpression
object. This is used to create an expression for an empty path. An empty path is basically the root element ".".- Parameters:
format
- the format used to style the paths created
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Method Details
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iterator
This is used to iterate over the path segments that have been extracted from the source XPath expression. Iteration over the segments is done in the order they were parsed from the source path. -
getIndex
public int getIndex()If the first path segment contains an index it is provided by this method. There may be several indexes within a path, however only the index at the first segment is issued by this method. If there is no index this will return 1.- Specified by:
getIndex
in interfaceExpression
- Returns:
- this returns the index of this path expression
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getPrefix
This is used to extract a namespace prefix from the path expression. A prefix is used to qualify the XML element name and does not form part of the actual path structure. This can be used to add the namespace in addition to the name.- Specified by:
getPrefix
in interfaceExpression
- Returns:
- this returns the prefix for the path expression
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getFirst
This can be used to acquire the first path segment within the expression. The first segment represents the parent XML element of the path. All segments returned do not contain any slashes and so represents the real element name.- Specified by:
getFirst
in interfaceExpression
- Returns:
- this returns the parent element for the path
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getLast
This can be used to acquire the last path segment within the expression. The last segment represents the leaf XML element of the path. All segments returned do not contain any slashes and so represents the real element name.- Specified by:
getLast
in interfaceExpression
- Returns:
- this returns the leaf element for the path
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getPath
This location contains the full path expression with all of the indexes explicitly shown for each path segment. This is used to create a uniform representation that can be used for comparisons of different path expressions.- Specified by:
getPath
in interfaceExpression
- Returns:
- this returns an expanded version of the path
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getElement
This is used to acquire the element path using this XPath expression. The element path is simply the fully qualified path for this expression with the provided name appended. If this is an empty path, the provided name is returned.- Specified by:
getElement
in interfaceExpression
- Parameters:
name
- this is the name of the element to be used- Returns:
- a fully qualified path for the specified name
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getAttribute
This is used to acquire the attribute path using this XPath expression. The attribute path is simply the fully qualified path for this expression with the provided name appended. If this is an empty path, the provided name is returned.- Specified by:
getAttribute
in interfaceExpression
- Parameters:
name
- this is the name of the attribute to be used- Returns:
- a fully qualified path for the specified name
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getPath
This allows an expression to be extracted from the current context. Extracting expressions in this manner makes it more convenient for navigating structures representing the XML document. If an expression can not be extracted with the given criteria an exception will be thrown.- Specified by:
getPath
in interfaceExpression
- Parameters:
from
- this is the number of segments to skip to- Returns:
- this returns an expression from this one
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getPath
This allows an expression to be extracted from the current context. Extracting expressions in this manner makes it more convenient for navigating structures representing the XML document. If an expression can not be extracted with the given criteria an exception will be thrown.- Specified by:
getPath
in interfaceExpression
- Parameters:
from
- this is the number of segments to skip totrim
- the number of segments to trim from the end- Returns:
- this returns an expression from this one
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isAttribute
public boolean isAttribute()This is used to determine if the expression points to an attribute value. An attribute value contains an '@' character before the last segment name. Such expressions distinguish element references from attribute references.- Specified by:
isAttribute
in interfaceExpression
- Returns:
- this returns true if the path has an attribute
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isPath
public boolean isPath()This is used to determine if the expression is a path. An expression represents a path if it contains more than one segment. If only one segment exists it is an element name.- Specified by:
isPath
in interfaceExpression
- Returns:
- true if this contains more than one segment
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isEmpty
public boolean isEmpty()This method is used to determine if this expression is an empty path. An empty path can be represented by a single period, '.'. It identifies the current path.- Specified by:
isEmpty
in interfaceExpression
- Returns:
- returns true if this represents an empty path
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