org.codehaus.plexus.util

Class InterpolationFilterReader

java.lang.Object

java.io.Reader

java.io.FilterReader

org.codehaus.plexus.util.InterpolationFilterReader

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable

public class InterpolationFilterReader
extends java.io.FilterReader

A FilterReader which interpolates keyword values into a character stream. Keywords are recognized when enclosed between starting and ending delimiter strings. The keywords themselves, and their values, are fetched from a Map supplied to the constructor.

When a possible keyword token is recognized (by detecting the starting and ending token delimiters):

• if the enclosed string is found in the keyword Map, the delimiters and the keyword are effectively replaced by the keyword's value;
• if the enclosed string is found in the keyword Map, but its value has zero length, then the token (delimiters and keyword) is effectively removed from the character stream;
• if the enclosed string is not found in the keyword Map, then no substitution is made; the token text is passed through unaltered.

See Also:

s

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	beginToken Character marking the beginning of a token.
private int	beginTokenLength Length of begin token.
private static java.lang.String	DEFAULT_BEGIN_TOKEN Default begin token.
private static java.lang.String	DEFAULT_END_TOKEN Default end token.
private java.lang.String	endToken Character marking the end of a token.
private int	endTokenLength Length of end token.
private int	previousIndex Index into previous data
private java.lang.String	replaceData replacement text from a token
private int	replaceIndex Index into replacement data
private java.util.Map<?,java.lang.Object>	variables Hashtable to hold the replacee-replacer pairs (String to String).

Fields inherited from class java.io.FilterReader

in

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
InterpolationFilterReader(java.io.Reader in, java.util.Map<?,java.lang.Object> variables, java.lang.String beginToken, java.lang.String endToken) Construct a Reader to interpolate values enclosed between the given delimiter tokens.
InterpolationFilterReader(java.io.Reader in, java.util.Map<java.lang.String,java.lang.Object> variables) Construct a Reader using the default interpolation delimiter tokens "${" and "}".

Method Summary

Modifier and Type	Method and Description
int	read() Returns the next character in the filtered stream, replacing tokens from the original stream.
int	read(char[] cbuf, int off, int len) Reads characters into a portion of an array.
long	skip(long n) Skips characters.

Methods inherited from class java.io.FilterReader

close, mark, markSupported, ready, reset

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

replaceData

private java.lang.String replaceData

replacement text from a token

replaceIndex

private int replaceIndex

Index into replacement data

previousIndex

private int previousIndex

Index into previous data

variables

private java.util.Map<?,java.lang.Object> variables

Hashtable to hold the replacee-replacer pairs (String to String).

beginToken

private java.lang.String beginToken

Character marking the beginning of a token.

endToken

private java.lang.String endToken

Character marking the end of a token.

beginTokenLength

private int beginTokenLength

Length of begin token.

endTokenLength

private int endTokenLength

Length of end token.

DEFAULT_BEGIN_TOKEN

private static final java.lang.String DEFAULT_BEGIN_TOKEN

Default begin token.

See Also:

Constant Field Values

DEFAULT_END_TOKEN

private static final java.lang.String DEFAULT_END_TOKEN

Default end token.

See Also:

Constant Field Values

Constructor Detail

InterpolationFilterReader

public InterpolationFilterReader(java.io.Reader in,
                                 java.util.Map<?,java.lang.Object> variables,
                                 java.lang.String beginToken,
                                 java.lang.String endToken)

Construct a Reader to interpolate values enclosed between the given delimiter tokens.

Parameters:

in - a Reader to be wrapped for interpolation.

variables - name/value pairs to be interpolated into the character stream.

beginToken - an interpolation target begins with this.

endToken - an interpolation target ends with this.

InterpolationFilterReader

public InterpolationFilterReader(java.io.Reader in,
                                 java.util.Map<java.lang.String,java.lang.Object> variables)

Construct a Reader using the default interpolation delimiter tokens "${" and "}".

Parameters:

in - a Reader to be wrapped for interpolation.

variables - name/value pairs to be interpolated into the character stream.

Method Detail

skip

public long skip(long n)
          throws java.io.IOException

Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

Overrides:

skip in class java.io.FilterReader

Parameters:

n - The number of characters to skip

Returns:

the number of characters actually skipped

Throws:

java.lang.IllegalArgumentException - If n is negative.

java.io.IOException - If an I/O error occurs

read

public int read(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException

Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Overrides:

read in class java.io.FilterReader

Parameters:

cbuf - Destination buffer to write characters to. Must not be null.

off - Offset at which to start storing characters.

len - Maximum number of characters to read.

Returns:

the number of characters read, or -1 if the end of the stream has been reached

Throws:

java.io.IOException - If an I/O error occurs

read

public int read()
         throws java.io.IOException

Returns the next character in the filtered stream, replacing tokens from the original stream.

Overrides:

read in class java.io.FilterReader

Returns:

the next character in the resulting stream, or -1 if the end of the resulting stream has been reached

Throws:

java.io.IOException - if the underlying stream throws an IOException during reading