EmptyAtomicSequence

java.lang.Object
- net.sf.saxon.om.EmptyAtomicSequence

All Implemented Interfaces:

java.lang.Iterable<AtomicValue>, AtomicSequence, GroundedValue, Sequence
```
public class EmptyAtomicSequence
extends java.lang.Object
implements AtomicSequence
```
An implementation of AtomicSequence that contains no items.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`effectiveBooleanValue()` Get the effective boolean value of this sequence
`UnicodeString`	`getCanonicalLexicalRepresentation()` Get the canonical lexical representation as defined in XML Schema.
`static EmptyAtomicSequence`	`getInstance()`
`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 a string representation of the sequence.
`AtomicValue`	`head()` Get the first item in the sequence
`AtomicValue`	`itemAt(int n)` Get the Nth item in the sequence, zero-based
`AtomicIterator`	`iterate()` Make an iterator over the items in the sequence
`java.util.Iterator<AtomicValue>`	`iterator()` Return a Java iterator over the atomic sequence.
`EmptyAtomicSequence`	`reduce()` Reduce the sequence to its simplest form.
`EmptyAtomicSequence`	`subsequence(int start, int length)` Get a subsequence of the value

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.GroundedValue
asIterable, concatenate, containsNode, materialize, toShortString

Methods inherited from interface net.sf.saxon.om.Sequence
makeRepeatable

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Method Detail
  - getInstance
```
public static EmptyAtomicSequence getInstance()
```
  - head
```
public AtomicValue head()
```
    Description copied from interface: AtomicSequence
    
    Get the first item in the sequence
    
    Specified by:
    
    head in interface AtomicSequence
    
    Specified by:
    
    head in interface GroundedValue
    
    Specified by:
    
    head in interface Sequence
    
    Returns:
    
    the first item in the sequence, or null if the sequence is empty
  - iterate
```
public AtomicIterator iterate()
```
    Description copied from interface: AtomicSequence
    
    Make an iterator over the items in the sequence
    
    Specified by:
    
    iterate in interface AtomicSequence
    
    Specified by:
    
    iterate in interface GroundedValue
    
    Specified by:
    
    iterate in interface Sequence
    
    Returns:
    
    an iterator over the items in the sequence
  - itemAt
```
public AtomicValue itemAt(int n)
```
    Description copied from interface: AtomicSequence
    
    Get the Nth item in the sequence, zero-based
    
    Specified by:
    
    itemAt in interface AtomicSequence
    
    Specified by:
    
    itemAt in interface GroundedValue
    
    Parameters:
    
    n - the index of the required item, with 0 representing the first item in the sequence
    
    Returns:
    
    the Nth item in the sequence, or null if the index is out of range
  - getLength
```
public int getLength()
```
    Description copied from interface: AtomicSequence
    
    Get the length of the sequence
    
    Specified by:
    
    getLength in interface AtomicSequence
    
    Specified by:
    
    getLength in interface GroundedValue
    
    Returns:
    
    the number of items in the sequence
  - getCanonicalLexicalRepresentation
```
public UnicodeString getCanonicalLexicalRepresentation()
```
    Get the canonical lexical representation as defined in XML Schema. This is not always the same as the result of casting to a string according to the XPath rules.
    
    Specified by:
    
    getCanonicalLexicalRepresentation in interface AtomicSequence
    
    Returns:
    
    the canonical lexical representation if defined in XML Schema; otherwise, the result of casting to string according to the XPath 2.0 rules
  - getUnicodeStringValue
```
public UnicodeString getUnicodeStringValue()
```
    Description copied from interface: AtomicSequence
    
    Get a string representation of the sequence. The is the space-separated concatenation of the result of casting each of the items in the sequence to xs:string
    
    Specified by:
    
    getUnicodeStringValue in interface AtomicSequence
    
    Specified by:
    
    getUnicodeStringValue in interface GroundedValue
    
    Returns:
    
    a whitespace-separated concatenation of the string values of the items making up the sequence, as a String.
  - getStringValue
```
public java.lang.String getStringValue()
```
    Description copied from interface: GroundedValue
    
    Get the string value of this sequence, as an instance of 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.
    
    Specified by:
    
    getStringValue in interface GroundedValue
    
    Returns:
    
    the string value of the sequence.
  - subsequence
```
public EmptyAtomicSequence subsequence(int start,
                                       int length)
```
    Get a subsequence of the value
    
    Specified by:
    
    subsequence in interface GroundedValue
    
    Parameters:
    
    start - 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 returned
    
    length - 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 sequence
    
    Returns:
    
    the required subsequence. If min is
  - effectiveBooleanValue
```
public boolean effectiveBooleanValue()
```
    Description copied from interface: GroundedValue
    
    Get the effective boolean value of this sequence
    
    Specified by:
    
    effectiveBooleanValue in interface GroundedValue
    
    Returns:
    
    the effective boolean value
  - reduce
```
public EmptyAtomicSequence reduce()
```
    Reduce the sequence to its simplest form. If the value is an empty sequence, the result will be EmptySequence.getInstance(). If the value is a single atomic value, the result will be an instance of AtomicValue. If the value is a single item of any other kind, the result will be an instance of SingletonItem. Otherwise, the result will typically be unchanged.
    
    Specified by:
    
    reduce in interface GroundedValue
    
    Returns:
    
    the simplified sequence
  - iterator
```
public java.util.Iterator<AtomicValue> iterator()
```
    Return a Java iterator over the atomic sequence.
    
    Specified by:
    
    iterator in interface java.lang.Iterable<AtomicValue>
    
    Returns:
    
    an Iterator.

Class EmptyAtomicSequence

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface net.sf.saxon.om.GroundedValue

Methods inherited from interface net.sf.saxon.om.Sequence

Methods inherited from interface java.lang.Iterable

Method Detail

getInstance

head

iterate

itemAt

getLength

getCanonicalLexicalRepresentation

getUnicodeStringValue

getStringValue

subsequence

effectiveBooleanValue

reduce

iterator