public class FilterIterator<T extends Item<?>> extends java.lang.Object implements SequenceIterator<T>
Modifier and Type | Class and Description |
---|---|
static class |
FilterIterator.NonNumeric<T extends Item<?>>
Subclass to handle the common special case where it is statically known
that the filter cannot return a numeric value
|
Modifier and Type | Field and Description |
---|---|
protected FocusIterator<T> |
base |
protected Expression |
filter |
protected XPathContext |
filterContext |
ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
Constructor and Description |
---|
FilterIterator(SequenceIterator<T> base,
Expression filter,
XPathContext context)
Constructor
|
Modifier and Type | Method and Description |
---|---|
void |
close()
Close the iterator.
|
protected T |
getNextMatchingItem()
Get the next item in the base sequence that matches the filter predicate
if there is such an item, or null if not.
|
int |
getProperties()
Get properties of this iterator, as a bit-significant integer.
|
protected boolean |
matches()
Determine whether the context item matches the filter predicate
|
T |
next()
Get the next item if there is one
|
void |
setSequence(SequenceIterator<?> base,
XPathContext context)
Set the base iterator
|
static boolean |
testPredicateValue(SequenceIterator iterator,
long position,
Expression filter) |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
forEachOrFail, materialize
protected FocusIterator<T extends Item<?>> base
protected Expression filter
protected XPathContext filterContext
public FilterIterator(SequenceIterator<T> base, Expression filter, XPathContext context)
base
- An iteration of the items to be filteredfilter
- The expression defining the filter predicatecontext
- The context in which the expression is being evaluatedpublic void setSequence(SequenceIterator<?> base, XPathContext context)
base
- the iterator over the sequence to be filteredcontext
- the context in which the (outer) filter expression is evaluatedpublic T next() throws XPathException
next
in interface SequenceIterator<T extends Item<?>>
XPathException
- if an error occurs retrieving the next itemprotected T getNextMatchingItem() throws XPathException
XPathException
- if a dynamic error occursprotected boolean matches() throws XPathException
XPathException
- if an error occurs evaluating the matchpublic static boolean testPredicateValue(SequenceIterator iterator, long position, Expression filter) throws XPathException
XPathException
public void close()
SequenceIterator
For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.
Closing an iterator is important when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.
close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in interface SequenceIterator<T extends Item<?>>
public int getProperties()
getProperties
in interface SequenceIterator<T extends Item<?>>
SequenceIterator.GROUNDED
, SequenceIterator.LAST_POSITION_FINDER
,
and SequenceIterator.LOOKAHEAD
. It is always
acceptable to return the value zero, indicating that there are no known special properties.
It is acceptable for the properties of the iterator to change depending on its state.Copyright (c) 2004-2020 Saxonica Limited. All rights reserved.