commons-io 1.3.2 · org.apache.commons.io.LineIterator

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 closeQuietly(LineIterator) method on the iterator.

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 {
  LineIterator.closeQuietly(iterator);
}

Modifier and Type	Field and Description
private final BufferedReader	bufferedReader The reader that is being read.
private String	cachedLine The current line.
private boolean	finished A flag indicating if the iterator has been fully read.

Constructor Summary

Access	Constructor and Description
public	LineIterator(final Reader the `Reader` to read from, not null reader) Constructs an iterator of the lines for a `Reader`.

Method Summary

Modifier and Type	Method and Description
public void	close() Closes the underlying `Reader` quietly.
public static void	closeQuietly(LineIterator the iterator to close iterator) Closes the iterator, handling null and ignoring exceptions.
public boolean	Returns: `true` if the Reader has more lines hasNext() Implements java.util.Iterator.hasNext. Indicates whether the `Reader` has more lines.
protected boolean	Returns: true if valid, false to remove from the iterator isValidLine(String the line that is to be validated line) Overridable method to validate each line that is returned.
public Object	Returns: the next line from the input next() Implements java.util.Iterator.next. Returns the next line in the wrapped `Reader`.
public String	Returns: the next line from the input nextLine() Returns the next line in the wrapped `Reader`.
public void	remove() Overrides default java.util.Iterator.remove. Unsupported.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

bufferedReader	back to summary
private final BufferedReader bufferedReader The reader that is being read.

cachedLine	back to summary
private String cachedLine The current line.

finished	back to summary
private boolean finished A flag indicating if the iterator has been fully read.

Constructor Detail

LineIterator back to summary

LineIterator	back to summary
public LineIterator(final Reader reader) throws IllegalArgumentException Constructs an iterator of the lines for a `Reader`. Parameters reader:Reader the `Reader` to read from, not null Exceptions IllegalArgumentException: if the reader is null

public LineIterator(final Reader reader) throws IllegalArgumentException

Constructs an iterator of the lines for a Reader.

Parameters

reader:Reader: the Reader to read from, not null

Exceptions

IllegalArgumentException:: if the reader is null

Method Detail

close	back to summary
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.

closeQuietly	back to summary
public static void closeQuietly(LineIterator iterator) Closes the iterator, handling null and ignoring exceptions. Parameters iterator:LineIterator the iterator to close

closeQuietly

back to summary

public static void closeQuietly(LineIterator iterator)

Closes the iterator, handling null and ignoring exceptions.

Parameters

iterator:LineIterator: the iterator to close

hasNext back to summary

hasNext	back to summary
public boolean hasNext() Implements java.util.Iterator.hasNext. Indicates whether the `Reader` has more lines. If there is an `IOException` then `close()` will be called on this instance. Returns:boolean `true` if the Reader has more lines Exceptions IllegalStateException: if an IO exception occurs

public boolean hasNext()

Implements java.util.Iterator.hasNext.

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

Returns:boolean

true if the Reader has more lines

Exceptions

IllegalStateException:: if an IO exception occurs

isValidLine	back to summary
protected boolean isValidLine(String line) Overridable method to validate each line that is returned. Parameters line:String the line that is to be validated Returns:boolean true if valid, false to remove from the iterator

isValidLine

back to summary

protected boolean isValidLine(String line)

Overridable method to validate each line that is returned.

Parameters

line:String: the line that is to be validated

Returns:boolean

true if valid, false to remove from the iterator

next back to summary

next	back to summary
public Object next() Implements java.util.Iterator.next. Returns the next line in the wrapped `Reader`. Returns:Object the next line from the input Exceptions NoSuchElementException: if there is no line to return

public Object next()

Implements java.util.Iterator.next.

Returns the next line in the wrapped Reader.

Returns:Object

the next line from the input

Exceptions

NoSuchElementException:: if there is no line to return

nextLine back to summary

nextLine	back to summary
public String nextLine() Returns the next line in the wrapped `Reader`. Returns:String the next line from the input Exceptions NoSuchElementException: if there is no line to return

public String nextLine()

Returns the next line in the wrapped Reader.

Returns:String

the next line from the input

Exceptions

NoSuchElementException:: if there is no line to return

remove	back to summary
public void remove() Overrides default java.util.Iterator.remove. Unsupported. Exceptions UnsupportedOperationException: always

remove

back to summary

public void remove()

Overrides default java.util.Iterator.remove.

Unsupported.

Exceptions

UnsupportedOperationException:: always

public Class LineIterator

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail