gov.nih.nlm.umls.io
Class PushBackReader

java.lang.Object
  java.io.Reader
      java.io.BufferedReader
          gov.nih.nlm.umls.io.PushBackReader

All Implemented Interfaces:

LocalNullValueSupport, Closeable, Readable

Direct Known Subclasses:

SearchStringPushBackReader

public class PushBackReader
extends BufferedReader
implements LocalNullValueSupport

Extends BufferedReader to provide the ability to push a single line of input back onto the reader to read it again on the next readLine() call.

Author:

Brian Carlsen

Field Summary

protected String	line
protected String	null_value
protected boolean	null_value_flag
protected String	regex_null_value

Fields inherited from class java.io.Reader

lock

Constructor Summary

PushBackReader(Reader r)
Instantiates a new PushBackReader wrapped around the specified reader.

PushBackReader(Reader r, int bufSize)
Instantiates a new PushBackReader wrapped around the specified reader.

Method Summary

String	getNullValue() Returns the null value.
boolean	isEmptyValue(String token) Indicates whether or not the specified token is null or contains a null value as defined by being either zero length or a value equal to the null value.
void	push(String line) Push a line of input back onto the reader.
String	readLine() Returns the next line from the reader.
protected String	resolveNull(String line) Replaces all "null value" characters in the line.
void	setNullValue(String null_value) Sets the null value to use.

Methods inherited from class java.io.BufferedReader

close, mark, markSupported, read, read, ready, reset, skip

Methods inherited from class java.io.Reader

read, read

Methods inherited from class java.lang.Object

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

Field Detail

line

protected String line

null_value

protected String null_value

regex_null_value

protected String regex_null_value

null_value_flag

protected boolean null_value_flag

Constructor Detail

PushBackReader

public PushBackReader(Reader r)

Instantiates a new PushBackReader wrapped around the specified reader.

Parameters:

r - BufferedReader

PushBackReader

public PushBackReader(Reader r,
                      int bufSize)

Instantiates a new PushBackReader wrapped around the specified reader.

Parameters:

r - BufferedReader

Method Detail

setNullValue

public void setNullValue(String null_value)

Sets the null value to use. This is needed if release.dat specifies some non-standard null value char sequence.

Specified by:

setNullValue in interface LocalNullValueSupport

Parameters:

null_value - the new null string value

getNullValue

public String getNullValue()

Returns the null value. This is needed if release.dat specifies some non-standard null value char sequence.

Specified by:

getNullValue in interface LocalNullValueSupport

Returns:

the string value for "null"

isEmptyValue

public boolean isEmptyValue(String token)

Indicates whether or not the specified token is null or contains a null value as defined by being either zero length or a value equal to the null value.

Specified by:

isEmptyValue in interface LocalNullValueSupport

readLine

public String readLine()
                throws IOException

Returns the next line from the reader.

Overrides:

readLine in class BufferedReader

Returns:

the next line from the reader

Throws:

IOException

resolveNull

protected String resolveNull(String line)

Replaces all "null value" characters in the line.

Parameters:

line - input line

Returns:

output line

push

public void push(String line)

Push a line of input back onto the reader.

Parameters:

line - input line to be pushed back on reader