Package org.apache.tools.ant.util

Class LayoutPreservingProperties

java.lang.Object

java.util.Dictionary<Object,Object>

java.util.Hashtable<Object,Object>

java.util.Properties

org.apache.tools.ant.util.LayoutPreservingProperties

All Implemented Interfaces:

Serializable, Cloneable, Map<Object,Object>

public class LayoutPreservingProperties
extends 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

Constructors

Constructor	Description
LayoutPreservingProperties()	Create a new, empty, Properties collection, with no defaults.
LayoutPreservingProperties(Properties defaults)	Create a new, empty, Properties collection, with the specified defaults.

Method Summary

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

Methods inherited from class java.util.Properties

compute, computeIfAbsent, computeIfPresent, contains, containsKey, containsValue, elements, entrySet, equals, forEach, get, getOrDefault, getProperty, getProperty, hashCode, isEmpty, keys, keySet, list, list, load, loadFromXML, merge, propertyNames, putAll, putIfAbsent, rehash, remove, replace, replace, replaceAll, save, size, store, storeToXML, storeToXML, storeToXML, stringPropertyNames, toString, values

Methods inherited from class java.lang.Object

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

Constructor Details

LayoutPreservingProperties

public LayoutPreservingProperties()

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

LayoutPreservingProperties

public LayoutPreservingProperties(Properties defaults)

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

Parameters:

defaults - the default property values

Method Details

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(InputStream inStream)
          throws IOException

Overrides:

load in class Properties

Throws:

IOException

put

public Object put(Object key,
 Object value)
           throws NullPointerException

Specified by:

put in interface Map<Object,Object>

Overrides:

put in class Properties

Throws:

NullPointerException

setProperty

public Object setProperty(String key,
 String value)
                   throws NullPointerException

Overrides:

setProperty in class Properties

Throws:

NullPointerException

clear

public void clear()

Specified by:

clear in interface Map<Object,Object>

Overrides:

clear in class Properties

remove

public Object remove(Object key)

Specified by:

remove in interface Map<Object,Object>

Overrides:

remove in class Properties

clone

public Object clone()

Overrides:

clone in class Properties

listLines

public void listLines(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(File dest)
            throws IOException

Save the properties to a file.

Parameters:

dest - the file to write to

Throws:

IOException - if save fails

store

public void store(OutputStream out,
 String header)
           throws IOException

Overrides:

store in class Properties

Throws:

IOException