net.sf.saxon.tree.iter

Class TextLinesIterator

java.lang.Object

net.sf.saxon.tree.iter.TextLinesIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, SequenceIterator

Direct Known Subclasses:

UnparsedTextIterator

public abstract class TextLinesIterator
extends java.lang.Object
implements SequenceIterator

An iterator that iterates over a file line by line, returning each line as a StringValue

Field Summary

Fields

Modifier and Type	Field and Description
protected IntPredicateProxy	checker
protected Location	location
protected java.io.LineNumberReader	reader
protected java.net.URI	uri

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TextLinesIterator()
	TextLinesIterator(java.io.LineNumberReader reader, Location location, java.net.URI uri, IntPredicateProxy checker) Create a TextLinesIterator over a given reader

Method Summary

Modifier and Type	Method and Description
void	close() Close the iterator.
void	discharge() Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence.
protected XPathException	handleIOError(java.net.URI uri, java.io.IOException err)
StringValue	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

Field Detail

reader

protected java.io.LineNumberReader reader

checker

protected IntPredicateProxy checker

location

protected Location location

uri

protected java.net.URI uri

Constructor Detail

TextLinesIterator

protected TextLinesIterator()

TextLinesIterator

public TextLinesIterator(java.io.LineNumberReader reader,
                         Location location,
                         java.net.URI uri,
                         IntPredicateProxy checker)
                  throws XPathException

Create a TextLinesIterator over a given reader

Parameters:

reader - the reader that reads the file

checker - checks that the characters in the file are legal XML characters

location - the location of the instruction being executed, for diagnostics. May be null.

uri - the URI of the file being read, for diagnostics

Throws:

XPathException - if a dynamic error occurs

Method Detail

next

public StringValue next()

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.

handleIOError

protected XPathException handleIOError(java.net.URI uri,
                                       java.io.IOException err)

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.

Closing an iterator is not necessary if the iterator is read to completion: if a call on SequenceIterator.next() returns null, the iterator will be closed automatically. An explicit call on SequenceIterator.close() is needed only when iteration is abandoned prematurely.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface SequenceIterator

discharge

public void discharge()

Description copied from interface: SequenceIterator

Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence. This may require the iterator to calculate the rest of the sequence eagerly. The method is called by a client if it anticipates that it might not read the iterator to completion, but it cannot guarantee that SequenceIterator.close() will be called when no more items are needed.

Specified by:

discharge in interface SequenceIterator