java.lang.Object
- java.io.Reader
- - java.io.FilterReader
  - - org.apache.sling.scripting.javascript.io.EspReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable
```
public class EspReader
extends FilterReader
```
The EspReader is a FilterReader which takes JSP like input and produces plain ECMA script output. The filtering modifications done on the input comprise the following :
- Template text (HTML) is wrapped by out.write(). At most one line of text is wrapped into a single write() call. Double quote characters in the template text (e.g. for HTML tag attribute values) are escaped.
- ECMA code is written to the output as is.
- ECMA slash star (/*) comments are also written as is.
- ECMA slash slash (//) comments are written as is.
- JSP style template comments (<%-- -->) are also removed from the stream. Lineendings (LFs and CRLFs) are written, though.
- HTML comments () are not treated specially. Rather they are handled as plain template text written to the output wrapped in out.write(). The consequence of this behaviour is, that as in JSP ECMA expressions may be included within the comments.
The nice thing about this reader is, that the line numbers of the resulting stream match the line numbers of the matching contents of the input stream. Due to the insertion of write() calls, column numbers will not necessarily match, though. This is especially true if you mix ECMA code tags (<% %>) with template text on the same line.
For maximum performance it is advisable to not create the EspReader with a plain FileReader or InputStreamReader but rather with a BufferedReader based on one of the simpler Readers. The reasons for this is, that we call the base reader character by character. This in turn is not too performing if the base reader does not buffer its input.

Field Summary

Fields
Modifier and Type Field Description

static String DEFAULT_OUT_INIT_STATEMENT
Javascript statement that sets the "out" variable that's used to output data.
- Fields inherited from class java.io.FilterReader
  in
- Fields inherited from class java.io.Reader
  lock

Constructor Summary

Constructors
Constructor Description

EspReader(Reader baseReader)
Create an EspReader on top of the given baseReader.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`	Close the EspReader.
`void`	`mark(int readAheadLimit)`	Mark the present position in the stream.
`boolean`	`markSupported()`	Tell whether this stream supports the mark() operation, which it does not.
`int`	`read()`	Return the next filtered character.
`int`	`read(char[] cbuf)`	Fill the given buffer with filtered or injected characters.
`int`	`read(char[] cbuf, int off, int len)`	Fill the buffer from the offset with the number of characters given.
`boolean`	`ready()`	Check whether we may block at the next read() operation.
`void`	`reset()`	Reset the stream.
`void`	`setOutInitStatement(String statement)`	Set the code fragment used to initialize the "out" variable
`long`	`skip(long n)`	Skip the number of filtered characters.

Methods inherited from class java.io.Reader
nullReader, read, transferTo

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DEFAULT_OUT_INIT_STATEMENT
```
public static final String DEFAULT_OUT_INIT_STATEMENT
```
    Javascript statement that sets the "out" variable that's used to output data. Automatically inserted by the reader in code, where needed.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - EspReader
```
public EspReader(Reader baseReader)
```
    Create an EspReader on top of the given baseReader. The constructor wraps the input reader with a PushbackReader, so that input stream modifications may be handled transparently by our doRead() method.
    
    Parameters:
    
    baseReader - the wrapped reader
- Method Detail
  - setOutInitStatement
```
public void setOutInitStatement(String statement)
```
    Set the code fragment used to initialize the "out" variable
    
    Parameters:
    
    statement - the statement used for initialization
  - ready
```
public boolean ready()
              throws IOException
```
    Check whether we may block at the next read() operation. We may be ready if and only if our input reader is ready. But this does not guarantee that we won't block, as due to filtering there may be more than one character needed from the input to return one.
    
    Overrides:
    
    ready in class FilterReader
    
    Returns:
    
    true if a character is available on the PushbackReader.
    
    Throws:
    
    IOException - if the reader is not open
  - read
```
public int read()
         throws IOException
```
    Return the next filtered character. This need not be the next character of the input stream. It may be a character from the input reader, after having skipped filtered characters or it may be a character injected due to translation of template text to ECMA code.
    
    Overrides:
    
    read in class FilterReader
    
    Returns:
    
    the next character after filtering or -1 at the end of the input reader
    
    Throws:
    
    IOException - if the reader is not open
  - read
```
public int read(char[] cbuf)
         throws IOException
```
    Fill the given buffer with filtered or injected characters. This need not be the next characters of the input stream. It may be characters from the input reader, after having skipped filtered characters or it may be a characters injected due to translation of template text to ECMA code. This method is exactly the same as read(cbuf, 0, cbuf.length).
    
    Overrides:
    
    read in class Reader
    
    Parameters:
    
    cbuf - The character buffer to fill with (filtered) characters
    
    Returns:
    
    the number of characters filled in the buffer or -1 at the end of the input reader.
    
    Throws:
    
    IOException - if the reader is not open
  - read
```
public int read(char[] cbuf,
                int off,
                int len)
         throws IOException
```
    Fill the buffer from the offset with the number of characters given. This need not be the next characters of the input stream. It may be characters from the input reader, after having skipped filtered characters or it may be a characters injected due to translation of template text to ECMA code.
    
    Overrides:
    
    read in class FilterReader
    
    Parameters:
    
    cbuf - The character buffer to fill with (filtered) characters
    
    off - Offset from where to start in the buffer
    
    len - The number of characters to fill into the buffer
    
    Returns:
    
    the number of characters filled in the buffer or -1 at the end of the input reader.
    
    Throws:
    
    IOException - if the reader is not open
    
    IndexOutOfBoundsException - if len is negative, off is negative or higher than the buffer length or off+len is negative or beyond the buffer size.
  - skip
```
public long skip(long n)
          throws IOException
```
    Skip the number of filtered characters. The skip method is the same as calling read() repeatedly for the given number of characters and throwing away the result. If the end of input reader is reached before having skipped the number of characters, the method returns the number characters skipped so far.
    
    Overrides:
    
    skip in class FilterReader
    
    Parameters:
    
    n - the number of (filtered) characters to skip
    
    Returns:
    
    the number of (filtered) characters actually skipped
    
    Throws:
    
    IllegalArgumentException - if n is negative
    
    IOException - if the reading the characters throws
  - close
```
public void close()
           throws IOException
```
    Close the EspReader.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface Closeable
    
    Overrides:
    
    close in class FilterReader
    
    Throws:
    
    IOException
  - mark
```
public void mark(int readAheadLimit)
          throws IOException
```
    Mark the present position in the stream. The mark for class EspReader always throws an throwable.
    
    Overrides:
    
    mark in class FilterReader
    
    Parameters:
    
    readAheadLimit - The number of characters to read ahead
    
    Throws:
    
    IOException - Always, since mark is not supported
  - markSupported
```
public boolean markSupported()
```
    Tell whether this stream supports the mark() operation, which it does not.
    
    Overrides:
    
    markSupported in class FilterReader
    
    Returns:
    
    false Always, since mark is not supported
  - reset
```
public void reset()
           throws IOException
```
    Reset the stream. The reset method of EspReader always throws an throwable.
    
    Overrides:
    
    reset in class FilterReader
    
    Throws:
    
    IOException - Always, since reset is not supported

Class EspReader

Field Summary

Fields inherited from class java.io.FilterReader

Fields inherited from class java.io.Reader

Constructor Summary

Method Summary

Methods inherited from class java.io.Reader

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_OUT_INIT_STATEMENT

Constructor Detail

EspReader

Method Detail

setOutInitStatement

ready

read

read

read

skip

close

mark

markSupported

reset