Package org.codehaus.plexus.util

Class 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 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 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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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

        nullReader, read, read, transferTo

      • 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