PropertyFile Task

# PropertyFile

by

- Thomas Christen (chr@active.ch)
- Jeremy Mawson (jem@loftinspace.com/au)

## Table of Contents

- Introduction
- PropertyFile Task
- Entry Task

## Introduction

Ant provides an optional task for editing property files. This is very useful when wanting to make unattended modifications to configuration files for application servers and applications. Currently, the task maintains a working property file with the ability to add properties or make changes to existing ones. However, any comments are lost.

## PropertyFile Task

### Parameters

Attribute | Description | Required
file | Location of the property file to be edited | Yes
comment | Header for the file itself | no

### Parameters specified as nested elements

#### Entry

Use nested `<entry>` elements to specify actual modifications to the property file itself.

Attribute | Description | Required
key | Name of the property name/value pair | Yes
value | Value to set (=), to add (+) or subtract (-) | At least one must be specified
default | Initial value to set for a property if it is not already defined in the property file. For type date, an additional keyword is allowed: "now"
type | Regard the value as : int, date or string (default) | No
operation | "+" or "=" (default) for all datatypes "-" (for date and int only). | No
pattern | For int and date type only. If present, Values will be parsed and formatted accordingly. | No
unit | The unit of the value to be applied to date +/- operations. Valid Values are: millisecond second minute hour day (default) week month year This only applies to date types using a +/- operation. | No

The rules used when setting a property value are shown below. The operation occurs after these rules are considered.

- If only value is specified, the property is set to it regardless of its previous value.
- If only default is specified and the property previously existed in the property file, it is unchanged.
- If only default is specified and the property did not exist in the property file, the property is set to default.
- If value and default are both specified and the property previously existed in the property file, the property is set to value.
- If value and default are both specified and the property did not exist in the property file, the property is set to default.

### Examples

The following changes the my.properties file. Assume my.properties look like:

    # A comment
    akey=novalue

After running, the file would now look like

    #Thu Nov 02 23:41:47 EST 2000
    akey=avalue
    adate=2000/11/02 23\:41
    anint=1
    formated.int=0014
    formated.date=028 17\:34

The slashes conform to the expectations of the Properties class. The file will be stored in a manner so that each character is examined and escaped if necessary. Note that the original comment is now lost. Please keep this in mind when running this task against heavily commented properties files. It may be best to have a commented version in the source tree, copy it to a deployment area, and then run the modifications on the copy. Future versions of PropertyFile will hopefully eliminate this shortcoming.

>     <propertyfile
>         file="my.properties"
>         comment="My properties">
>       <entry  key="akey" value="avalue"/>
>       <entry  key="adate" type="date" value="now"/>
>       <entry  key="anint" type="int" operation="+"/>
>       <entry  key="formated.int" type="int" default="0013" operation="+" pattern="0000"/>
>       <entry  key="formated.date" type="date" value="now" pattern="DDD HH:mm"/>
>     </propertyfile>

To produce dates relative from today :

>     <propertyfile
>         file="my.properties"
>         comment="My properties">
>       <entry  key="formated.date-1"
>           type="date" default="now" pattern="DDD"
>           operation="-" value="1"/>
>       <entry  key="formated.tomorrow"
>           type="date" default="now" pattern="DDD"
>           operation="+" value="1"/>
>     </propertyfile>

Concatenation of strings :

>     <propertyfile
>         file="my.properties"
>         comment="My properties">
>       <entry  key="progress" default="" operation="+" value="."/>
>     </propertyfile>

Each time called, a "." will be appended to "progress"

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