Package org.apache.tools.ant.filters

# Class ExpandProperties

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

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`, `Readable`, `ChainableReader`

public final class ExpandProperties extends BaseFilterReader implements ChainableReader
Expands Ant properties, if any, in the data.

Example:

    <expandproperties/>

Or:

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

## Field Summary

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

`in`

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

`lock`

## Constructor Summary

Constructors
Constructor
Description
`ExpandProperties()`
Constructor for "dummy" instances.
`ExpandProperties(Reader in)`
Creates a new filtered reader.

## Method Summary

Modifier and Type
Method
Description
`void`
`add(PropertySet propertySet)`
Restrict the expanded properties using a PropertySet.
`Reader`
`chain(Reader rdr)`
Creates a new ExpandProperties filter using the passed in Reader for instantiation.
`int`
`read()`
Returns the next character in the filtered stream.

### 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

`nullReader, read, read, transferTo`

### Methods inherited from class java.lang.Object

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

## Constructor Details

### ExpandProperties

public ExpandProperties()
Constructor for "dummy" instances.

See Also:
  - `BaseFilterReader()`

### ExpandProperties

public ExpandProperties(Reader in)
Creates a new filtered reader.

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

## Method Details

### add

public void add(PropertySet propertySet)
Restrict the expanded properties using a PropertySet.

Parameters:
  `propertySet` - replacement lookup

### read

public int read() throws IOException
Returns the next character in the filtered stream. The original stream is first read in fully, and the Ant properties are expanded. The results of this expansion are then queued so they can be read character-by-character.

Overrides:
  `read` in class `FilterReader`
Returns:
  the next character in the resulting stream, or -1 if the end of the resulting stream has been reached
Throws:
  `IOException` - if the underlying stream throws an IOException during reading

### chain

public Reader chain(Reader rdr)
Creates a new ExpandProperties filter 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