net.sf.saxon.value

Class SequenceSlice

java.lang.Object

net.sf.saxon.value.SequenceSlice

All Implemented Interfaces:

GroundedValue, Sequence

public class SequenceSlice
extends java.lang.Object
implements GroundedValue

A sequence value implemented extensionally. That is, this class represents a sequence by allocating memory to each item in the sequence.

Constructor Summary

Constructors

Constructor and Description
SequenceSlice(java.util.List<? extends Item> value, int offset, int length) Construct an sequence from a slice of a list of items.

Method Summary

Modifier and Type	Method and Description
java.lang.Iterable<? extends Item>	asIterable() Get the contents of this value in the form of a Java Iterable, so that it can be used in a for-each expression
int	getCardinality() Determine the cardinality
int	getLength() Get the number of items in the sequence
java.lang.String	getStringValue() Get the string value of this sequence.
java.lang.CharSequence	getStringValueCS() Get the string value of this sequence.
Item	head() Get the first item in the sequence.
Item	itemAt(int n) Get the n'th item in the sequence (starting with 0 as the first item)
ListIterator<? extends Item>	iterate() Return an iterator over this sequence.
java.util.Iterator<? extends Item>	iterator() Get an iterator (a Java Iterator) over the items in this sequence.
GroundedValue	reduce() Reduce the sequence to its simplest form.
GroundedValue	subsequence(int start, int length) Get a subsequence of the value
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

concatenate, containsNode, effectiveBooleanValue, materialize, toShortString

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

makeRepeatable

Constructor Detail

SequenceSlice

public SequenceSlice(java.util.List<? extends Item> value,
                     int offset,
                     int length)

Construct an sequence from a slice of a list of items. Note, the list of items is used as is, which means the caller must not subsequently change its contents.

Parameters:

value - the list of items

offset - the zero-based position of the first item to be included in the sequence

length - the number of items to be included in the sequence; if this exceeds the number of items available for inclusion, include all items up to the end of the sequence

Throws:

java.lang.IndexOutOfBoundsException - if offset < 0 or length < 0 or offset + length < value.size()

Method Detail

getStringValue

public java.lang.String getStringValue()
                                throws XPathException

Description copied from interface: GroundedValue

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

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

Description copied from interface: GroundedValue

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

Returns:

the string value of the sequence.

Throws:

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

head

public Item head()

Get the first item in the sequence.

Specified by:

head in interface GroundedValue

Specified by:

head in interface Sequence

Returns:

the first item in the sequence if there is one, or null if the sequence is empty

getLength

public int getLength()

Get the number of items in the sequence

Specified by:

getLength in interface GroundedValue

Returns:

the number of items in the sequence

getCardinality

public int getCardinality()

Determine the cardinality

Returns:

the cardinality of the sequence, using the constants defined in net.sf.saxon.value.Cardinality

See Also:

Cardinality

itemAt

public Item itemAt(int n)

Get the n'th item in the sequence (starting with 0 as the first item)

Specified by:

itemAt in interface GroundedValue

Parameters:

n - the position of the required item

Returns:

the n'th item in the sequence, or null if the position is out of range

iterate

public ListIterator<? extends Item> iterate()

Return an iterator over this sequence.

Specified by:

iterate in interface GroundedValue

Specified by:

iterate in interface Sequence

Returns:

the required SequenceIterator, positioned at the start of the sequence

subsequence

public GroundedValue 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

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

reduce

public GroundedValue 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

Returns:

the simplified sequence

asIterable

public java.lang.Iterable<? extends Item> asIterable()

Get the contents of this value in the form of a Java Iterable, so that it can be used in a for-each expression

Specified by:

asIterable in interface GroundedValue

Returns:

an Iterable containing the same sequence of items

iterator

public java.util.Iterator<? extends Item> iterator()

Get an iterator (a Java Iterator) over the items in this sequence.

Returns:

an iterator over the items in this sequence.