Class PropertiesConfiguration

  • All Implemented Interfaces:
    java.lang.Cloneable, Configuration, EventSource, FileBasedConfiguration, ImmutableConfiguration, FileBased, FileLocatorAware, SynchronizerSupport

    public class PropertiesConfiguration
    extends BaseConfiguration
    implements FileBasedConfiguration, FileLocatorAware
    This is the "classic" Properties loader which loads the values from a single or multiple files (which can be chained with "include =". All given path references are either absolute or relative to the file name supplied in the constructor.

    In this class, empty PropertyConfigurations can be built, properties added and later saved. include statements are (obviously) not supported if you don't construct a PropertyConfiguration from a file.

    The properties file syntax is explained here, basically it follows the syntax of the stream parsed by Properties.load(java.io.Reader) and adds several useful extensions:

    • Each property has the syntax key <separator> value. The separators accepted are '=', ':' and any white space character. Examples:
        key1 = value1
        key2 : value2
        key3   value3
    • The key may use any character, separators must be escaped:
        key\:foo = bar
    • value may be separated on different lines if a backslash is placed at the end of the line that continues below.
    • The list delimiter facilities provided by AbstractConfiguration are supported, too. If an appropriate ListDelimiterHandler is set (for instance a D efaultListDelimiterHandler object configured with a comma as delimiter character), value can contain value delimiters and will then be interpreted as a list of tokens. So the following property definition
        key = This property, has multiple, values
       
      will result in a property with three values. You can change the handling of delimiters using the AbstractConfiguration.setListDelimiterHandler(ListDelimiterHandler) method. Per default, list splitting is disabled.
    • Commas in each token are escaped placing a backslash right before the comma.
    • If a key is used more than once, the values are appended like if they were on the same line separated with commas. Note: When the configuration file is written back to disk the associated PropertiesConfigurationLayout object (see below) will try to preserve as much of the original format as possible, i.e. properties with multiple values defined on a single line will also be written back on a single line, and multiple occurrences of a single key will be written on multiple lines. If the addProperty() method was called multiple times for adding multiple values to a property, these properties will per default be written on multiple lines in the output file, too. Some options of the PropertiesConfigurationLayout class have influence on that behavior.
    • Blank lines and lines starting with character '#' or '!' are skipped.
    • If a property is named "include" (or whatever is defined by setInclude() and getInclude() and the value of that property is the full path to a file on disk, that file will be included into the configuration. You can also pull in files relative to the parent configuration file. So if you have something like the following: include = additional.properties Then "additional.properties" is expected to be in the same directory as the parent configuration file. The properties in the included file are added to the parent configuration, they do not replace existing properties with the same key.
    • You can define custom error handling for the special key "include" by using setIncludeListener(ConfigurationConsumer).

    Here is an example of a valid extended properties file:

          # lines starting with # are comments
    
          # This is the simplest property
          key = value
    
          # A long property may be separated on multiple lines
          longvalue = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
                      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    
          # This is a property with many tokens
          tokens_on_a_line = first token, second token
    
          # This sequence generates exactly the same result
          tokens_on_multiple_lines = first token
          tokens_on_multiple_lines = second token
    
          # commas may be escaped in tokens
          commas.escaped = Hi\, what'up?
    
          # properties can reference other properties
          base.prop = /base
          first.prop = ${base.prop}/first
          second.prop = ${first.prop}/second
     

    A PropertiesConfiguration object is associated with an instance of the PropertiesConfigurationLayout class, which is responsible for storing the layout of the parsed properties file (i.e. empty lines, comments, and such things). The getLayout() method can be used to obtain this layout object. With setLayout() a new layout object can be set. This should be done before a properties file was loaded.

    Like other Configuration implementations, this class uses a Synchronizer object to control concurrent access. By choosing a suitable implementation of the Synchronizer interface, an instance can be made thread-safe or not. Note that access to most of the properties typically set through a builder is not protected by the Synchronizer. The intended usage is that these properties are set once at construction time through the builder and after that remain constant. If you wish to change such properties during life time of an instance, you have to use the lock() and unlock() methods manually to ensure that other threads see your changes.

    As this class extends AbstractConfiguration, all basic features like variable interpolation, list handling, or data type conversions are available as well. This is described in the chapter Basic features and AbstractConfiguration of the user's guide. There is also a separate chapter dealing with Properties files in special.

    See Also:
    Properties.load(java.io.Reader)
    • Field Detail

      • DEFAULT_INCLUDE_LISTENER

        public static final ConfigurationConsumer<ConfigurationException> DEFAULT_INCLUDE_LISTENER
        Defines default error handling for the special "include" key by throwing the given exception.
        Since:
        2.6
      • DEFAULT_ENCODING

        public static final java.lang.String DEFAULT_ENCODING
        The default encoding (ISO-8859-1 as specified by http://java.sun.com/j2se/1.5.0/docs/api/java/util/Properties.html)
        See Also:
        Constant Field Values
    • Constructor Detail

      • PropertiesConfiguration

        public PropertiesConfiguration()
        Creates an empty PropertyConfiguration object which can be used to synthesize a new Properties file by adding values and then saving().
    • Method Detail

      • getInclude

        public static java.lang.String getInclude()
        Gets the property value for including other properties files. By default it is "include".
        Returns:
        A String.
      • getIncludeOptional

        public static java.lang.String getIncludeOptional()
        Gets the property value for including other properties files. By default it is "includeoptional".

        If the file is absent, processing continues normally.

        Returns:
        A String.
        Since:
        2.5
      • setInclude

        public static void setInclude​(java.lang.String inc)
        Sets the property value for including other properties files. By default it is "include".
        Parameters:
        inc - A String.
      • setIncludeOptional

        public static void setIncludeOptional​(java.lang.String inc)
        Sets the property value for including other properties files. By default it is "include".

        If the file is absent, processing continues normally.

        Parameters:
        inc - A String.
        Since:
        2.5
      • setIncludesAllowed

        public void setIncludesAllowed​(boolean includesAllowed)
        Controls whether additional files can be loaded by the include = <xxx> statement or not. This is true per default.
        Parameters:
        includesAllowed - True if Includes are allowed.
      • isIncludesAllowed

        public boolean isIncludesAllowed()
        Reports the status of file inclusion.
        Returns:
        True if include files are loaded.
      • getHeader

        public java.lang.String getHeader()
        Return the comment header.
        Returns:
        the comment header
        Since:
        1.1
      • setHeader

        public void setHeader​(java.lang.String header)
        Set the comment header.
        Parameters:
        header - the header to use
        Since:
        1.1
      • getFooter

        public java.lang.String getFooter()
        Returns the footer comment. This is a comment at the very end of the file.
        Returns:
        the footer comment
        Since:
        2.0
      • setFooter

        public void setFooter​(java.lang.String footer)
        Sets the footer comment. If set, this comment is written after all properties at the end of the file.
        Parameters:
        footer - the footer comment
        Since:
        2.0
      • getLayout

        public PropertiesConfigurationLayout getLayout()
        Returns the associated layout object.
        Returns:
        the associated layout object
        Since:
        1.3
      • setLayout

        public void setLayout​(PropertiesConfigurationLayout layout)
        Sets the associated layout object.
        Parameters:
        layout - the new layout object; can be null, then a new layout object will be created
        Since:
        1.3
      • getIOFactory

        public PropertiesConfiguration.IOFactory getIOFactory()
        Returns the IOFactory to be used for creating readers and writers when loading or saving this configuration.
        Returns:
        the IOFactory
        Since:
        1.7
      • setIncludeListener

        public void setIncludeListener​(ConfigurationConsumer<ConfigurationException> includeListener)
        Sets the current include listener, may not be null.
        Parameters:
        includeListener - the current include listener, may not be null.
        Throws:
        java.lang.IllegalArgumentException - if the includeListener is null.
        Since:
        2.6
      • setIOFactory

        public void setIOFactory​(PropertiesConfiguration.IOFactory ioFactory)
        Sets the IOFactory to be used for creating readers and writers when loading or saving this configuration. Using this method a client can customize the reader and writer classes used by the load and save operations. Note that this method must be called before invoking one of the load() and save() methods. Especially, if you want to use a custom IOFactory for changing the PropertiesReader, you cannot load the configuration data in the constructor.
        Parameters:
        ioFactory - the new IOFactory (must not be null)
        Throws:
        java.lang.IllegalArgumentException - if the IOFactory is null
        Since:
        1.7
      • initFileLocator

        public void initFileLocator​(FileLocator locator)
        Stores the current FileLocator for a following IO operation. The FileLocator is needed to resolve include files with relative file names.
        Specified by:
        initFileLocator in interface FileLocatorAware
        Parameters:
        locator - the current FileLocator
        Since:
        2.0
      • read

        public void read​(java.io.Reader in)
                  throws ConfigurationException,
                         java.io.IOException
        Reads the content of this object from the given reader. Client code should not call this method directly, but use a FileHandler for reading data. This implementation delegates to the associated layout object which does the actual loading. Note that this method does not do any synchronization. This lies in the responsibility of the caller. (Typically, the caller is a FileHandler object which takes care for proper synchronization.)
        Specified by:
        read in interface FileBased
        Parameters:
        in - the reader
        Throws:
        ConfigurationException - if a non-I/O related problem occurs, e.g. the data read does not have the expected format
        java.io.IOException - if an I/O error occurs
        Since:
        2.0
      • write

        public void write​(java.io.Writer out)
                   throws ConfigurationException,
                          java.io.IOException
        Writes the content of this object to the given writer. Client code should not call this method directly, but use a FileHandler for writing data. This implementation delegates to the associated layout object which does the actual saving. Note that, analogous to read(Reader), this method does not do any synchronization.
        Specified by:
        write in interface FileBased
        Parameters:
        out - the writer
        Throws:
        ConfigurationException - if a non-I/O related problem occurs, e.g. the data read does not have the expected format
        java.io.IOException - if an I/O error occurs
        Since:
        2.0
      • clone

        public java.lang.Object clone()
        Creates a copy of this object.
        Overrides:
        clone in class BaseConfiguration
        Returns:
        the copy
      • unescapeJava

        protected static java.lang.String unescapeJava​(java.lang.String str)

        Unescapes any Java literals found in the String to a Writer.

        This is a slightly modified version of the StringEscapeUtils.unescapeJava() function in commons-lang that doesn't drop escaped separators (i.e '\,').
        Parameters:
        str - the String to unescape, may be null
        Returns:
        the processed string
        Throws:
        java.lang.IllegalArgumentException - if the Writer is null
      • unescapeJava

        protected static java.lang.String unescapeJava​(java.lang.String str,
                                                       boolean jupCompatible)
        Unescapes Java literals found in the String to a Writer.

        When the parameter jupCompatible is false, the classic behavior is used (see unescapeJava(String)). When it's true a slightly different behavior that's compatible with Properties is used (see PropertiesConfiguration.JupIOFactory).

        Parameters:
        str - the String to unescape, may be null
        jupCompatible - whether unescaping is compatible with Properties; otherwise the classic behavior is used
        Returns:
        the processed string
        Throws:
        java.lang.IllegalArgumentException - if the Writer is null