org.sape.carbon.core.config.type
Class TokenReplacer

java.lang.Object
  |
  +--org.sape.carbon.core.config.type.TokenReplacer

class TokenReplacer

extends Object

This class provides tokenization and value linking for configuration values in order to minimize the duplication of data. It supports two types of value replacement, document property and deployment property.

The Document Property has a form of {document-name$attribute-name}. This would search for a document named document-name and then look for an attribute named attribute-name.

The Deployment Property lookup has a form of {deployment-property}. This would retrieve the Deployment Property deployment-property from the BootStrapper. This mechanism should not be used for normal configurations and is specially provided for instances where deployment values can not or do not want to be known ahead of time (such as the base file-system directory of config or a database password).

Since:

carbon 1.0

Version:

$Revision: 1.19 $($Author: dvoet $ / $Date: 2003/05/05 21:21:20 $)

Author:

Douglas Voet, April 2002

See Also:

Copyright 2002 Sapient

Field Summary

private static String	ALL_DELIMETERS Delimiters to tokenize on.
private static String	ATTRIBUTE_DELIMETER The delimeter used for seperating a config document name from the value that is required from it.
private static String	BEGIN_DELIMETER The delimiter that begins a replaceable config value
private String	data The data to be tokenized, mapped and replaced necessary.
private static String	END_DELIMETER The end delimter that declares the end of a replaceable config value
private static String	ESCAPE_DELIMETER The character set used to escape other delimeters so that they can be used as real values.
private org.apache.commons.logging.Log	log Provides a handle to Apache-commons logger
private String	replacedValue The replaced value of the data.

Constructor Summary

TokenReplacer(String data)
Creates a new token replacer for the specified configuration value.

Method Summary

boolean	containsTokens() Tests if the data contains tokens.
private String	lookupConfigurationValue(String configName, String attributeName) Looks up a Configuration value from the Config using token replacement.
String	replaceTokens() Replaces tokens within configuration attributes with values from other configurations.

Methods inherited from class java.lang.Object

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

Field Detail

log

private org.apache.commons.logging.Log log

Provides a handle to Apache-commons logger

BEGIN_DELIMETER

private static final String BEGIN_DELIMETER

The delimiter that begins a replaceable config value

See Also:

Constant Field Values

END_DELIMETER

private static final String END_DELIMETER

The end delimter that declares the end of a replaceable config value

See Also:

Constant Field Values

ATTRIBUTE_DELIMETER

private static final String ATTRIBUTE_DELIMETER

The delimeter used for seperating a config document name from the value that is required from it.

See Also:

Constant Field Values

ESCAPE_DELIMETER

private static final String ESCAPE_DELIMETER

The character set used to escape other delimeters so that they can be used as real values.

See Also:

Constant Field Values

ALL_DELIMETERS

private static final String ALL_DELIMETERS

Delimiters to tokenize on.

See Also:

Constant Field Values

data

private String data

The data to be tokenized, mapped and replaced necessary.

replacedValue

private String replacedValue

The replaced value of the data.

Constructor Detail

TokenReplacer

public TokenReplacer(String data)

Creates a new token replacer for the specified configuration value.

Parameters:

data - the data to run the replacer on

Method Detail

containsTokens

public boolean containsTokens()

Tests if the data contains tokens.

Returns:

if the data contains tokens

replaceTokens

public String replaceTokens()
                     throws ConfigurationTypeException

Replaces tokens within configuration attributes with values from other configurations. Tokens are in the form of {configuration name$attribute name}. If either '{', '}' or '$' are required in the actual value, escape them with a '\'.

Returns:

String the String to tokenize and replace

Throws:

ConfigurationTypeException - thrown when unable to retrieve a referenced value or in case there is a failure parse the reference.

lookupConfigurationValue

private String lookupConfigurationValue(String configName,
                                        String attributeName)
                                 throws TokenReplacementException

Looks up a Configuration value from the Config using token replacement.

Parameters:

configName - name of the configuration to lookup

attributeName - name of the attribute to retreive from config

Returns:

the String value of the configuration

Throws:

TokenReplacementException - indicates an error retreiving the value from the configuration