org.jmxtrans.agent.util

Class PropertyPlaceholderResolver

java.lang.Object

org.jmxtrans.agent.util.PropertyPlaceholderResolver

All Implemented Interfaces:

Serializable

public class PropertyPlaceholderResolver
extends Object
implements Serializable

Inspired by Spring Property placeholder mechanism.

Placeholders are delimited by '{' and '}' and support default value with ':'. Sample : '{graphite.host}' or '{graphite.port:2003}'.

If the placeholder is not found in the system properties, it is searched in the environment variables and then converted to underscore delimited upper case and searched in environment variables.

Sample for '{graphite.port:2003}':

1. System.getProperty("graphite.port")
2. System.getenv("graphite.port")
3. System.getenv("GRAPHITE_PORT")
4. default to 2003

Author:

Cyrille Le Clerc

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
PropertyPlaceholderResolver()

Method Summary

Methods

Modifier and Type	Method and Description
protected String	resolvePlaceholder(String property, String defaultValue) Search for the given placeholder in system properties then in environment variables.
String	resolveString(String string) Parse the given string resolving property placeholders (${my-property[:default-value]})

Methods inherited from class java.lang.Object

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

Constructor Detail

PropertyPlaceholderResolver

public PropertyPlaceholderResolver()

Method Detail

resolveString

public String resolveString(String string)
                     throws IllegalStateException

Parse the given string resolving property placeholders (${my-property[:default-value]})

Parameters:

string - the string to parse.

Returns:

the parsed string. Non null.

Throws:

IllegalStateException - a property placeholder could not be resolved and no default value has been defined.

resolvePlaceholder

protected String resolvePlaceholder(String property,
                        String defaultValue)
                             throws IllegalStateException

Search for the given placeholder in system properties then in environment variables.

Parameters:

property - property to resolve

defaultValue - Default value if the placeholder is not found. null means not default value is defined and the placeholder must exist

Returns:

the resolved property or the default value if the placeholder is not found and the default value is defined. Non null.

Throws:

IllegalStateException - if the placeholder is not found and the given defaultValue is not defined (null)