org.apache.tools.ant.util
Class LayoutPreservingProperties

java.lang.Object
  java.util.Dictionary<K,V>
      java.util.Hashtable<java.lang.Object,java.lang.Object>
          java.util.Properties
              org.apache.tools.ant.util.LayoutPreservingProperties

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map<java.lang.Object,java.lang.Object>

public class LayoutPreservingProperties
extends java.util.Properties

A Properties collection which preserves comments and whitespace present in the input stream from which it was loaded.

The class defers the usual work of the java.util.Properties class to there, but it also keeps track of the contents of the input stream from which it was loaded (if applicable), so that it can write out the properties in as close a form as possible to the input.

If no changes occur to property values, the output should be the same as the input, except for the leading date stamp, as normal for a properties file. Properties added are appended to the file. Properties whose values are changed are changed in place. Properties that are removed are excised. If the removeComments flag is set, then the comments immediately preceding the property are also removed.

If a second set of properties is loaded into an existing set, the lines of the second set are added to the end. Note however, that if a property already stored is present in a stream subsequently loaded, then that property is removed before the new value is set. For example, consider the file

 # the first line
 alpha=one

 # the second line
 beta=two

This file is loaded, and then the following is also loaded into the same LayoutPreservingProperties object

 # association
 beta=band

 # and finally
 gamma=rays

The resulting collection sequence of logical lines depends on whether or not removeComments was set at the time the second stream is loaded. If it is set, then the resulting list of lines is

 # the first line
 alpha=one

 # association
 beta=band

 # and finally
 gamma=rays

If the flag is not set, then the comment "the second line" is retained, although the key-value pair beta=two is removed.

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.Properties

defaults

Constructor Summary

LayoutPreservingProperties()
Create a new, empty, Properties collection, with no defaults.

LayoutPreservingProperties(java.util.Properties defaults)
Create a new, empty, Properties collection, with the specified defaults.

Method Summary

void	clear()
java.lang.Object	clone()
boolean	isRemoveComments() Returns true if comments are removed along with properties, or false otherwise.
void	listLines(java.io.PrintStream out) Echo the lines of the properties (including blanks and comments) to the stream.
void	load(java.io.InputStream inStream)
java.lang.Object	put(java.lang.Object key, java.lang.Object value)
java.lang.Object	remove(java.lang.Object key)
void	saveAs(java.io.File dest) Save the properties to a file.
java.lang.Object	setProperty(java.lang.String key, java.lang.String value)
void	setRemoveComments(boolean val) Sets the behaviour for comments accompanying properties that are being removed.
void	store(java.io.OutputStream out, java.lang.String header)

Methods inherited from class java.util.Properties

getProperty, getProperty, list, list, loadFromXML, propertyNames, save, storeToXML, storeToXML

Methods inherited from class java.util.Hashtable

contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keys, keySet, putAll, rehash, size, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

LayoutPreservingProperties

public LayoutPreservingProperties()

Create a new, empty, Properties collection, with no defaults.

LayoutPreservingProperties

public LayoutPreservingProperties(java.util.Properties defaults)

Create a new, empty, Properties collection, with the specified defaults.

Parameters:

defaults - the default property values

Method Detail

isRemoveComments

public boolean isRemoveComments()

Returns true if comments are removed along with properties, or false otherwise. If true, then when a property is removed, the comment preceding it in the original file is removed also.

Returns:

true if leading comments are removed when a property is removed; false otherwise

setRemoveComments

public void setRemoveComments(boolean val)

Sets the behaviour for comments accompanying properties that are being removed. If true, then when a property is removed, the comment preceding it in the original file is removed also.

Parameters:

val - true if leading comments are to be removed when a property is removed; false otherwise

load

public void load(java.io.InputStream inStream)
          throws java.io.IOException

Overrides:

load in class java.util.Properties

Throws:

java.io.IOException

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)
                     throws java.lang.NullPointerException

Specified by:

put in interface java.util.Map<java.lang.Object,java.lang.Object>

Overrides:

put in class java.util.Hashtable<java.lang.Object,java.lang.Object>

Throws:

java.lang.NullPointerException

setProperty

public java.lang.Object setProperty(java.lang.String key,
                                    java.lang.String value)
                             throws java.lang.NullPointerException

Overrides:

setProperty in class java.util.Properties

Throws:

java.lang.NullPointerException

clear

public void clear()

Specified by:

clear in interface java.util.Map<java.lang.Object,java.lang.Object>

Overrides:

clear in class java.util.Hashtable<java.lang.Object,java.lang.Object>

remove

public java.lang.Object remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<java.lang.Object,java.lang.Object>

Overrides:

remove in class java.util.Hashtable<java.lang.Object,java.lang.Object>

clone

public java.lang.Object clone()

Overrides:

clone in class java.util.Hashtable<java.lang.Object,java.lang.Object>

listLines

public void listLines(java.io.PrintStream out)

Echo the lines of the properties (including blanks and comments) to the stream.

Parameters:

out - the stream to write to

saveAs

public void saveAs(java.io.File dest)
            throws java.io.IOException

Save the properties to a file.

Parameters:

dest - the file to write to

Throws:

java.io.IOException

store

public void store(java.io.OutputStream out,
                  java.lang.String header)
           throws java.io.IOException

Overrides:

store in class java.util.Properties

Throws:

java.io.IOException