com.bigdata.util

Class PropertyUtil

java.lang.Object

com.bigdata.util.PropertyUtil

public class PropertyUtil
extends Object

This utility class provides helper methods designed to fuse two configurations in which at least one of the configuration is represented as a Properties object, which may have a system of inherited defaults. When a Map and a Properties object or two Properties objects must be combined in a "fused" configuration, it may be necessary to "flatten" a Properties object such that all inherited properties are placed within a simple Map. This reduces the problem to fusing two maps, which may be done using Map.putAll( Map other ).

Under some circumstances, it may be desirable to report a conflict which would otherwise be silently ignored by Map.putAll( Map other ). A helper method has been provided to report such conflicts rather than letting one Map override another.

Constructor Summary

Constructors

Constructor and Description
PropertyUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static Properties	convert(Map configParams)
static Properties	flatCopy(Properties props) Return a flatten copy of the specified Properties.
static Map	flatten(Properties properties) Return a Map that provides a flattened view of a Properties object.
static Properties	fuse(Map defaults, Map override) Fuses two configurations and ignores any conflicts.
static Properties	fuse(Map defaults, Map override, boolean ignoreConflicts) Fuses two configurations and optionally reports any conflicts.
static void	list(String msg, Properties properties, PrintStream ps) Lists all entries defined either directly by a Properties object or at any level within its defaults hierarchy.

Methods inherited from class java.lang.Object

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

Constructor Detail

PropertyUtil

public PropertyUtil()

Method Detail

flatCopy

public static Properties flatCopy(Properties props)

Return a flatten copy of the specified Properties. The returned object does not share any structure with the source object, but it does share key and value references. Since keys and values are Strings for a Properties instance this SHOULD NOT be a problem. The behavior is equivalent to:

 Properties tmp = new Properties();
 tmp.putAll(flatten(props));
 

except that it handles null values.

Parameters:

props - The properties to be flattened and copied.

Returns:

A flat copy.

flatten

public static Map flatten(Properties properties)

Return a Map that provides a flattened view of a Properties object.

For each level of the Properties object, visit all keys and then resolve each key against the top-level Properties object placing the result into the output Map. The order of visitation of the Properties levels does not matter since the value of the key is always defined against the top-level Properties object which handles any defaults correctly.

     a) Example overwrites any shared keys in p1 with the definitions for
     those keys in p2.

        Properties p1 = ...;
        Properties p2 = ...;

        p1.putAll( flatten( p2 ) );

     b) Examples in which a Map and a Properties object are fused.

        Map m1 = ...;
        Properties p1 = ....;

        // Override m1 with p1.
        m1.putAll( flatten( p1 ) );

        vs.

        // Override p1 with m1.
        p1.putAll( m1 );

        

list

public static void list(String msg,
        Properties properties,
        PrintStream ps)

Lists all entries defined either directly by a Properties object or at any level within its defaults hierarchy.

fuse

public static Properties fuse(Map defaults,
              Map override)

Fuses two configurations and ignores any conflicts.

Parameters:

defaults - The default configuration.

override - Another configuration whose values will be fused with the defaults. If this is a Properties object then it is first flattened so that any inherited property values will be fused.

Returns:

A Properties object. If defaults was a Properties object, then this is defaults and any values from override have been added to defaults. Otherwise a new Properties object is created, the entries from defaults are copied into that Properties object, and any values from override are copied onto that Properties object.

fuse

public static Properties fuse(Map defaults,
              Map override,
              boolean ignoreConflicts)

Fuses two configurations and optionally reports any conflicts.

Parameters:

defaults - The default configuration.

override - Another configuration whose values will be fused with the defaults. If this is a Properties object then it is first flattened so that any inherited property values will be fused.

ignoreConflicts - When true an exception is not reported if an entry from override would override an entry in defaults.

Returns:

A Properties object. If defaults was a Properties object, then this is defaults and any values from override have been added to defaults. Otherwise a new Properties object is created, the entries from defaults are copied into that Properties object, and any values from override are copied onto that Properties object.

convert

public static Properties convert(Map configParams)