com.landawn.abacus.util

Class LineIterator

java.lang.Object

com.landawn.abacus.util.LineIterator

All Implemented Interfaces:

Immutable, Closeable, AutoCloseable, Iterator<String>

public final class LineIterator
extends Object
implements Closeable

Note: it's copied from Apache Commons IO developed at The Apache Software Foundation (http://www.apache.org/), or under the Apache License 2.0. An Iterator over the lines in a Reader.

LineIterator holds a reference to an open Reader. When you have finished with the iterator you should close the reader to free internal resources. This can be done by closing the reader directly, or by calling the close() or #closeAllQuietly(LineIterator) method on the iterator.

The recommended usage pattern is:

 try(LineIterator it = FileUtils.lineIterator(file, "UTF-8")) {
   while (it.hasNext()) {
     String line = it.nextLine();
     // do something with line
   }
 }
 

Since:

1.2

Version:

$Id: LineIterator.java 1471767 2013-04-24 23:24:19Z sebb $

Constructor Summary

Constructors

Constructor and Description
LineIterator(Reader reader) Constructs an iterator of the lines for a Reader.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the underlying Reader quietly.
<E extends Exception> void	foreachIndexed(Throwables.IndexedConsumer<? super String,E> action)
<E extends Exception> void	foreachRemaining(Throwables.Consumer<? super String,E> action)
boolean	hasNext() Indicates whether the Reader has more lines.
String	next() Returns the next line in the wrapped Reader.
static LineIterator	of(File file) Returns an Iterator for the lines in a File using the default encoding for the VM.
static LineIterator	of(File file, Charset encoding) Returns an Iterator for the lines in a File.
static LineIterator	of(InputStream input)
static LineIterator	of(InputStream input, Charset encoding) Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).
static LineIterator	of(Reader reader)
void	remove() Deprecated. - UnsupportedOperationException
<C extends Collection<T>> C	toCollection(Supplier<? extends C> supplier)
ImmutableList<T>	toImmutableList()
ImmutableSet<T>	toImmutableSet()
Set<T>	toSet()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

LineIterator

public LineIterator(Reader reader)
             throws IllegalArgumentException

Constructs an iterator of the lines for a Reader.

Parameters:

reader - the Reader to read from, not null

Throws:

IllegalArgumentException - if the reader is null

Method Detail

of

public static LineIterator of(File file)

Returns an Iterator for the lines in a File using the default encoding for the VM.

This method opens an InputStream for the file. When you have finished with the iterator you should close the stream to free internal resources. This can be done by calling the close() or IOUtil#closeQuietly(LineIterator) method.

The recommended usage pattern is:

 LineIterator it = FileUtils.lineIterator(file, "UTF-8");
 try {
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   closeQuietly(iterator);
 }
 

If an exception occurs during the creation of the iterator, the underlying stream is closed. file the file to open for input, must not be null

Returns:

an Iterator of the lines in the file, never null

Throws:

UncheckedIOException - in case of an I/O error (file closed)

See Also:

#lineIterator(File, Charset)

of

public static LineIterator of(File file,
                              Charset encoding)

Returns an Iterator for the lines in a File.

This method opens an InputStream for the file. When you have finished with the iterator you should close the stream to free internal resources. This can be done by calling the close() or IOUtil#closeQuietly(LineIterator) method.

The recommended usage pattern is:

 LineIterator it = FileUtils.lineIterator(file, "UTF-8");
 try {
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   closeQuietly(iterator);
 }
 

If an exception occurs during the creation of the iterator, the underlying stream is closed. file the file to open for input, must not be null encoding the encoding to use, null means platform default

Returns:

an Iterator of the lines in the file, never null

Throws:

UncheckedIOException - in case of an I/O error (file closed)

of

public static LineIterator of(InputStream input)

Parameters:

input -

Returns:

of

public static LineIterator of(InputStream input,
                              Charset encoding)
                       throws UncheckedIOException

Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).

LineIterator holds a reference to the open InputStream specified here. When you have finished with the iterator you should close the stream to free internal resources. This can be done by closing the stream directly, or by calling close() or IOUtil#closeQuietly(LineIterator).

The recommended usage pattern is:

 try {
   LineIterator it = lineIterator(stream, charset);
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   closeQuietly(stream);
 }
 

input the InputStream to read from, not null encoding the encoding to use, null means platform default

Returns:

an Iterator of the lines in the reader, never null

Throws:

IllegalArgumentException - if the input is null

UncheckedIOException - if an I/O error occurs, such as if the encoding is invalid

of

public static LineIterator of(Reader reader)

Parameters:

reader -

Returns:

hasNext

public boolean hasNext()

Indicates whether the Reader has more lines. If there is an IOException then close() will be called on this instance.

Specified by:

hasNext in interface Iterator<String>

Returns:

true if the Reader has more lines

Throws:

IllegalStateException - if an IO exception occurs

next

public String next()

Returns the next line in the wrapped Reader.

Specified by:

next in interface Iterator<String>

Returns:

Throws:

NoSuchElementException - if there is no line to return

foreachRemaining

public <E extends Exception> void foreachRemaining(Throwables.Consumer<? super String,E> action)
                                            throws E extends Exception

Type Parameters:

E -

Parameters:

action -

Throws:

E - the e

E extends Exception

foreachIndexed

public <E extends Exception> void foreachIndexed(Throwables.IndexedConsumer<? super String,E> action)
                                          throws E extends Exception

Type Parameters:

E -

Parameters:

action -

Throws:

E - the e

E extends Exception

close

public void close()

Closes the underlying Reader quietly. This method is useful if you only want to process the first few lines of a larger file. If you do not close the iterator then the Reader remains open. This method can safely be called multiple times.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

remove

@Deprecated
public void remove()
                         throws UnsupportedOperationException

Deprecated. - UnsupportedOperationException

Specified by:

remove in interface Iterator<T>

Throws:

UnsupportedOperationException

toSet

public Set<T> toSet()

toCollection

public <C extends Collection<T>> C toCollection(Supplier<? extends C> supplier)

Type Parameters:

C -

Parameters:

supplier -

Returns:

toImmutableList

public ImmutableList<T> toImmutableList()

toImmutableSet

public ImmutableSet<T> toImmutableSet()