Class 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

      Constructors 
      Constructor Description
      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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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

        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 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.Properties
        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.Properties
      • 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.Properties
      • clone

        public java.lang.Object clone()
        Overrides:
        clone in class java.util.Properties
      • 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 - if save fails
      • 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