net.sf.saxon.value

Class SequenceSlice<T extends Item<?>>

java.lang.Object

net.sf.saxon.value.SequenceSlice<T>

All Implemented Interfaces:

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

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

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<T> 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<T>	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.
T	head() Get the first item in the sequence.
T	itemAt(int n) Get the n'th item in the sequence (starting with 0 as the first item)
ListIterator<T>	iterate() Return an iterator over this sequence.
java.util.Iterator<T>	iterator() Get an iterator (a Java Iterator) over the items in this sequence.
GroundedValue<T>	reduce() Reduce the sequence to its simplest form.
GroundedValue<T>	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

effectiveBooleanValue, materialize, toShortString

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

makeRepeatable

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

SequenceSlice

public SequenceSlice(java.util.List<T> 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<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

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<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)

head

public T head()

Get the first item in the sequence.

Specified by:

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

Specified by:

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

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<T extends Item<?>>

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 T itemAt(int n)

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

Specified by:

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

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<T> iterate()

Return an iterator over this sequence.

Specified by:

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

Specified by:

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

Returns:

the required SequenceIterator, positioned at the start of the sequence

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. If min is

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

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

asIterable

public java.lang.Iterable<T> 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<T extends Item<?>>

Specified by:

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

Returns:

an Iterable containing the same sequence of items

iterator

public java.util.Iterator<T> iterator()

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

Specified by:

iterator in interface java.lang.Iterable<T extends Item<?>>

Specified by:

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

Returns:

an iterator over the items in this sequence.