public final class EmptySequence extends java.lang.Object implements GroundedValue
Modifier and Type | Method and Description |
---|---|
boolean |
effectiveBooleanValue()
Get the effective boolean value - always false
|
boolean |
equals(java.lang.Object other)
Is this expression the same as another expression?
|
static EmptySequence |
getInstance()
Get the implicit instance of this class
|
int |
getLength()
Get the length of the sequence
|
java.lang.String |
getStringValue()
Get the string value of this sequence, as an instance of
String . |
UnicodeString |
getUnicodeStringValue()
Get the string value of this sequence, as an instance of
UnicodeString . |
int |
hashCode() |
Item |
head()
Get the first item in the sequence.
|
Item |
itemAt(int n)
Get the n'th item in the sequence (starting from 0).
|
SequenceIterator |
iterate()
Return an iteration over the sequence
|
GroundedValue |
reduce()
Reduce the sequence to its simplest form.
|
GroundedValue |
subsequence(int min,
int length)
Get a subsequence of the value
|
java.lang.String |
toString()
Returns a string representation of the object.
|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
asIterable, concatenate, containsNode, materialize, toShortString
makeRepeatable
public static EmptySequence getInstance()
public UnicodeString getUnicodeStringValue()
GroundedValue
UnicodeString
.
The string value of an item is the result of applying the XPath string()
function. The string value of a sequence is the space-separated result of applying the string-join() function
using a single space as the separator
The result of this method is always equivalent to the result of the GroundedValue.getStringValue()
method.
Use this method in preference either (a) if you need to use the value in a context where a UnicodeString
is required, or (b) if the underlying value is held as a UnicodeString
, or in a form that is readily
converted to a UnicodeString
. This is typically the case (i) when the value is a text or element node
in a TinyTree, and (ii) when the value is a StringItem
: that is, an atomic value of type
xs:string
.
getUnicodeStringValue
in interface GroundedValue
public java.lang.String getStringValue()
GroundedValue
String
.
The string value of an item is the result of applying the XPath string()
function. The string value of a sequence is the space-separated result of applying the string-join() function
using a single space as the separator.
The result of this method is always equivalent to the result of the GroundedValue.getUnicodeStringValue()
method.
Use this method in preference either (a) if you need to use the value in a context where a String
is required, or (b) if the underlying value is held as a String
, or in a form that is readily
converted to a String
. This is typically the case (i) when the value is an attribute node
in a TinyTree, or (ii) any kind of node in a third-party tree model such as DOM.
getStringValue
in interface GroundedValue
public Item head()
head
in interface GroundedValue
head
in interface Sequence
public SequenceIterator iterate()
iterate
in interface GroundedValue
iterate
in interface Sequence
public final int getLength()
getLength
in interface GroundedValue
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
java.lang.ClassCastException
- if the values are not comparablepublic int hashCode()
hashCode
in class java.lang.Object
public boolean effectiveBooleanValue()
effectiveBooleanValue
in interface GroundedValue
public Item itemAt(int n)
itemAt
in interface GroundedValue
n
- position of the required item, counting from zero.public GroundedValue subsequence(int min, int length)
subsequence
in interface GroundedValue
min
- the index of the first item to be included in the result, counting from zero.
A negative value is taken as zero. If the value is beyond the end of the sequence, an empty
sequence is returnedlength
- the number of items to be included in the result. Specify Integer.MAX_VALUE to
get the subsequence up to the end of the base sequence. If the value is negative, an empty sequence
is returned. If the value goes off the end of the sequence, the result returns items up to the end
of the sequencepublic java.lang.String toString()
toString
in class java.lang.Object
public GroundedValue reduce()
reduce
in interface GroundedValue
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