org.apache.tools.ant.filters

## Class ClassConstants

- java.lang.Object
- - java.io.Reader
  - - java.io.FilterReader
    - - org.apache.tools.ant.filters.BaseFilterReader
      - - org.apache.tools.ant.filters.ClassConstants

All Implemented Interfaces:
  java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable, ChainableReader

    public final class ClassConstants
    extends BaseFilterReader
    implements ChainableReader

Assembles the constants declared in a Java class in `key1=value1(line separator)key2=value2` format.

Notes:

1. This filter uses the BCEL external toolkit.
2. This assembles only those constants that are not created using the syntax `new whatever()`
3. This assembles constants declared using the basic datatypes and String only.
4. The access modifiers of the declared constants do not matter.

Example:

    <classconstants/>

Or:

    <filterreader
        classname="org.apache.tools.ant.filters.ClassConstants"/>

### Field Summary

### Fields inherited from class java.io.FilterReader

`in`

### Fields inherited from class java.io.Reader

`lock`

### Constructor Summary

Constructors
Constructor and Description
`ClassConstants()` Constructor for "dummy" instances.
`ClassConstants(java.io.Reader in)` Creates a new filtered reader.

### Method Summary

All Methods Instance Methods Concrete Methods
`java.io.Reader` `chain(java.io.Reader rdr)` Creates a new ClassConstants using the passed in Reader for instantiation.
`int` `read()` Reads and assembles the constants declared in a class file.

### Methods inherited from class org.apache.tools.ant.filters.BaseFilterReader

`getInitialized, getProject, read, readFully, readLine, setInitialized, setProject, skip`

### 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`

### Constructor Detail

#### ClassConstants

    public ClassConstants()

Constructor for "dummy" instances.

See Also:
  `BaseFilterReader.BaseFilterReader()`

#### ClassConstants

    public ClassConstants(java.io.Reader in)

Creates a new filtered reader. The contents of the passed-in reader are expected to be the name of the class from which to produce a list of constants.

Parameters:
  `in` - A Reader object providing the underlying stream. Must not be `null`.

### Method Detail

#### read

    public int read()
             throws java.io.IOException

Reads and assembles the constants declared in a class file.

Overrides:
  `read` in class `java.io.FilterReader`
Returns:
  the next character in the list of constants, 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, or if the constants for the specified class cannot be read (for example due to the class not being found).

#### chain

    public java.io.Reader chain(java.io.Reader rdr)

Creates a new ClassConstants using the passed in Reader for instantiation.

Specified by:
  `chain` in interface `ChainableReader`
Parameters:
  `rdr` - A Reader object providing the underlying stream. Must not be `null`.
Returns:
  a new filter based on this configuration, but filtering the specified reader