net.sf.saxon.om

Class ZeroOrMore<T extends Item<?>>

java.lang.Object

net.sf.saxon.om.ZeroOrMore<T>

All Implemented Interfaces:

java.lang.Iterable<T>, GroundedValue<T>, Sequence<T>

public class ZeroOrMore<T extends Item<?>>
extends java.lang.Object
implements GroundedValue<T>

A value that is a sequence containing one or more items. The main use is in declarations of reflexive extension functions, where declaring an argument of type <ZeroOrMore<IntegerValue>> triggers automatic type checking in the same way as for a native XSLT/XQuery function declaring the type as xs:integer*.

Constructor Summary

Constructors

Constructor and Description
ZeroOrMore(java.util.List<T> content)
ZeroOrMore(SequenceIterator<? extends T> iter)
ZeroOrMore(T[] content) Create a sequence containing zero or one items

Method Summary

Modifier and Type	Method and Description
boolean	effectiveBooleanValue() Get the effective boolean value of this sequence
int	getLength() Get the size of the value (the number of items)
java.lang.String	getStringValue() Get the string value of this sequence.
java.lang.CharSequence	getStringValueCS() Get the string value of this sequence.
T	head() Get the first item of the sequence.
T	itemAt(int n) Get the n'th item in the value, counting from 0
UnfailingIterator<T>	iterate() Get an iterator over all the items in the sequence.
GroundedValue<T>	reduce() Reduce the sequence to its simplest form.
GroundedValue<T>	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, iterator, materialize, toShortString

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

makeRepeatable

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ZeroOrMore

public ZeroOrMore(T[] content)

Create a sequence containing zero or one items

Parameters:

content - The content of the sequence

ZeroOrMore

public ZeroOrMore(java.util.List<T> content)

ZeroOrMore

public ZeroOrMore(SequenceIterator<? extends T> iter)
           throws XPathException

Throws:

XPathException

Method Detail

head

public T head()

Description copied from interface: GroundedValue

Get the first item of the sequence. This differs from the parent interface in not allowing an exception

Specified by:

head in interface GroundedValue<T extends Item<?>>

Specified by:

head in interface Sequence<T extends Item<?>>

Returns:

the first item of the sequence, or null if the sequence is empty

iterate

public UnfailingIterator<T> iterate()

Description copied from interface: GroundedValue

Get an iterator over all the items in the sequence. This differs from the superclass method in not allowing an exception, either during this method call, or in the subsequent processing of the returned iterator.

Specified by:

iterate in interface GroundedValue<T extends Item<?>>

Specified by:

iterate in interface Sequence<T extends Item<?>>

Returns:

an iterator (meaning a Saxon SequenceIterator rather than a Java Iterator) over all the items in this Sequence.

itemAt

public T itemAt(int n)

Get the n'th item in the value, counting from 0

Specified by:

itemAt in interface GroundedValue<T extends Item<?>>

Parameters:

n - the index of the required item, with 0 representing the first item in the sequence

Returns:

the n'th item if it exists, or null otherwise

subsequence

public GroundedValue<T> subsequence(int start,
                                    int length)

Get a subsequence of the value

Specified by:

subsequence in interface GroundedValue<T extends Item<?>>

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.

getLength

public int getLength()

Get the size of the value (the number of items)

Specified by:

getLength in interface GroundedValue<T extends Item<?>>

Returns:

the number of items in the sequence

effectiveBooleanValue

public boolean effectiveBooleanValue()
                              throws XPathException

Get the effective boolean value of this sequence

Specified by:

effectiveBooleanValue in interface GroundedValue<T extends Item<?>>

Returns:

the effective boolean value

Throws:

XPathException - if the sequence has no effective boolean value (for example a sequence of two integers)

getStringValue

public java.lang.String getStringValue()
                                throws XPathException

Get the string value of this sequence. The string value of an item is the result of applying the 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

Specified by:

getStringValue in interface GroundedValue<T extends Item<?>>

Returns:

the string value of the sequence.

Throws:

XPathException - if the sequence contains items that have no string value (for example, function items)

getStringValueCS

public java.lang.CharSequence getStringValueCS()
                                        throws XPathException

Get the string value of this sequence. The string value of an item is the result of applying the 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

Specified by:

getStringValueCS in interface GroundedValue<T extends Item<?>>

Returns:

the string value of the sequence.

Throws:

XPathException - if the sequence contains items that have no string value (for example, function items)

reduce

public GroundedValue<T> 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 One. Otherwise, the result will typically be unchanged.

Specified by:

reduce in interface GroundedValue<T extends Item<?>>

Returns:

the simplified sequence