Package de.xima.fc.common.io

Class SubstitutingWriter

java.lang.Object

java.io.Writer

de.xima.fc.common.io.SubstitutingWriter

All Implemented Interfaces:

Closeable, Flushable, Appendable, AutoCloseable

public final class SubstitutingWriter
extends Writer

Wraps a writer and applies substitutions "source -> target" to the content.

Tokens are searched for and replaced in the order they are given. Usually, it is recommended to provide tokens in order of decreasing length, to ensure that longer tokens are replaced before shorter tokens that are contained in the longer tokens. For example, if you want to replace "abc" with "x" and "ab" with "y", you should provide the source tokens in the order "abc", "ab"; and the target tokens in the order "x", "y". If you provide the source tokens in the order "ab", "abc"; and the target tokens in the order "y", "x", the result will be that "abc" is replaced with "yc" instead of "x".

The implementation implements a lookahead equal to the largest source token, then inspects each character and checks if it is the start of any source token. If yes, writes the previous content to the writer, then skips the source token and writes the replacement target token instead.

Note: Flushing this writer does not flush characters that are still in the lookahead buffer, as they have not yet been processed for substitutions.

This writer is not thread-safe and must be synchronized externally if used by multiple threads.

Since:

8.5.4

Field Summary

Fields inherited from class java.io.Writer

lock

Constructor Summary

Constructors

Constructor	Description
SubstitutingWriter(Writer writer, char[][] sourceTokens, char[][] targetTokens)	Creates a new substituting writer that applies the given substitutions to the content written to the given writer.
SubstitutingWriter(Writer writer, String[] sourceTokens, String[] targetTokens)	Creates a new substituting writer that applies the given substitutions to the content written to the given writer.

Method Summary

Modifier and Type	Method	Description
void	close()
void	flush()
void	write(char[] chars, int off, int len)

Methods inherited from class java.io.Writer

append, append, append, nullWriter, write, write, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

SubstitutingWriter

public SubstitutingWriter(Writer writer,
                          char[][] sourceTokens,
                          char[][] targetTokens)

Creates a new substituting writer that applies the given substitutions to the content written to the given writer. The target tokens array should not contain more tokens than the source tokens array. Extra tokens are ignored. If there are fewer target tokens than source tokens, the last target token is used as replacement.

Parameters:

writer - The writer to wrap. Must not be null.

sourceTokens - The source tokens to replace. Must not be null or empty, and every token must have a length greater than 0.

targetTokens - The target tokens to replace with. Must not be null or empty.

SubstitutingWriter

public SubstitutingWriter(Writer writer,
                          String[] sourceTokens,
                          String[] targetTokens)

Creates a new substituting writer that applies the given substitutions to the content written to the given writer. The target tokens array should not contain more tokens than the source tokens array. Extra tokens are ignored. If there are fewer target tokens than source tokens, the last target token is used as replacement.

Parameters:

writer - The writer to wrap. Must not be null.

sourceTokens - The source tokens to replace. Must not be null or empty.

targetTokens - The target tokens to replace with. Must not be null or empty.

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Writer

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Specified by:

flush in class Writer

Throws:

IOException

write

public void write(char[] chars,
                  int off,
                  int len)
           throws IOException

Specified by:

write in class Writer

Throws:

IOException