GroupMatchingIterator

java.lang.Object
- net.sf.saxon.expr.sort.GroupMatchingIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, GroupIterator, SequenceIterator, LookaheadIterator

Direct Known Subclasses:

GroupEndingIterator, GroupStartingIterator
```
public abstract class GroupMatchingIterator
extends java.lang.Object
implements LookaheadIterator, LastPositionFinder, GroupIterator
```
A GroupMatchingIterator contains code shared between GroupStartingIterator and GroupEndingIterator

Nested Class Summary
- Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator
  SequenceIterator.Property

Field Summary

Fields
Modifier and Type	Field and Description
`protected XPathContext`	`baseContext`
`protected Item`	`current`
`protected java.util.List<Item>`	`currentMembers`
`protected Item`	`next`
`protected Pattern`	`pattern`
`protected FocusIterator`	`population`
`protected int`	`position`
`protected XPathContext`	`runningContext`
`protected Expression`	`select`

Constructor Summary

Constructors
Constructor and Description

GroupMatchingIterator()

Constructors
Constructor and Description
`GroupMatchingIterator()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected abstract void`	`advance()`
`void`	`close()` Close the iterator.
`AtomicSequence`	`getCurrentGroupingKey()` Get the grouping key of the current group
`java.util.EnumSet<SequenceIterator.Property>`	`getProperties()` Get properties of this iterator.
`com.saxonica.ee.stream.ManualGroupIterator`	`getSnapShot(XPathContext context)` Get a sequence which is a snapshot of this sequence at the current position
`boolean`	`hasNext()` Determine whether there are more items to come.
`SequenceIterator`	`iterateCurrentGroup()` Get an iterator over the members of the current group, in population order.
`Item`	`next()` Get the next item in the sequence.

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.expr.LastPositionFinder
getLength

Methods inherited from interface net.sf.saxon.om.SequenceIterator
forEachOrFail, materialize

- Field Detail
  - select
```
protected Expression select
```
  - population
```
protected FocusIterator population
```
  - pattern
```
protected Pattern pattern
```
  - baseContext
```
protected XPathContext baseContext
```
  - runningContext
```
protected XPathContext runningContext
```
  - currentMembers
```
protected java.util.List<Item> currentMembers
```
  - next
```
protected Item next
```
  - current
```
protected Item current
```
  - position
```
protected int position
```
- Constructor Detail
  - GroupMatchingIterator
```
public GroupMatchingIterator()
```
- Method Detail
  - advance
```
protected abstract void advance()
                         throws XPathException
```
    Throws:
    
    XPathException
  - getCurrentGroupingKey
```
public AtomicSequence getCurrentGroupingKey()
```
    Description copied from interface: GroupIterator
    
    Get the grouping key of the current group
    
    Specified by:
    
    getCurrentGroupingKey in interface GroupIterator
    
    Returns:
    
    the current grouping key in the case of group-by or group-adjacent, or null in the case of group-starting-with and group-ending-with
  - iterateCurrentGroup
```
public SequenceIterator iterateCurrentGroup()
```
    Description copied from interface: GroupIterator
    
    Get an iterator over the members of the current group, in population order. This must always be a clean iterator, that is, an iterator that starts at the first item of the group.
    
    Specified by:
    
    iterateCurrentGroup in interface GroupIterator
    
    Returns:
    
    an iterator over all the members of the current group, in population order.
  - hasNext
```
public boolean hasNext()
```
    Description copied from interface: LookaheadIterator
    
    Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.
    This method must not be called unless the result of getProperties() on the iterator includes the property SequenceIterator.Property.LOOKAHEAD
    
    Specified by:
    
    hasNext in interface LookaheadIterator
    
    Returns:
    
    true if there are more items in the sequence
  - next
```
public Item next()
          throws XPathException
```
    Description copied from interface: SequenceIterator
    
    Get the next item in the sequence. This method changes the state of the iterator.
    
    Specified by:
    
    next in interface SequenceIterator
    
    Returns:
    
    the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.
    
    Throws:
    
    XPathException - if an error occurs retrieving the next item
  - close
```
public void close()
```
    Description copied from interface: SequenceIterator
    
    Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.
    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.
    
    Specified by:
    
    close in interface java.io.Closeable
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
    
    Specified by:
    
    close in interface SequenceIterator
  - getProperties
```
public java.util.EnumSet<SequenceIterator.Property> getProperties()
```
    Description copied from interface: SequenceIterator
    
    Get properties of this iterator.
    
    Specified by:
    
    getProperties in interface SequenceIterator
    
    Returns:
    
    the properties of this iterator. This will be some combination of properties such as SequenceIterator.Property.GROUNDED, SequenceIterator.Property.LAST_POSITION_FINDER, and SequenceIterator.Property.LOOKAHEAD. It is always acceptable to return the default value EnumSet.noneOf(Property.class), indicating that there are no known special properties. It is acceptable (though unusual) for the properties of the iterator to change depending on its state.
  - getSnapShot
```
public com.saxonica.ee.stream.ManualGroupIterator getSnapShot(XPathContext context)
```
    Description copied from interface: GroupIterator
    
    Get a sequence which is a snapshot of this sequence at the current position
    
    Specified by:
    
    getSnapShot in interface GroupIterator

Class GroupMatchingIterator

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface net.sf.saxon.expr.LastPositionFinder

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

Field Detail

select

population

pattern

baseContext

runningContext

currentMembers

next

current

position

Constructor Detail

GroupMatchingIterator

Method Detail

advance

getCurrentGroupingKey

iterateCurrentGroup

hasNext

next

close

getProperties

getSnapShot