Convert Java properties file to sed commands using ant

 HOWTO

•  https://gemini.google.com/app
•  https://ant-contrib.sourceforge.net/
• https://ant-contrib.sourceforge.net/tasks/tasks/for.html 
• Get  antcontrib.jar via Maven  https://mvnrepository.com/artifact/ant-contrib/ant-contrib/1.0b3
• https://stackoverflow.com/questions/3056395/how-can-i-iterate-over-properties-from-a-file 
• https://stackoverflow.com/questions/7102793/how-to-put-a-newline-in-ant-property 
• AntContrib propertyselector https://ant-contrib.sourceforge.net/tasks/tasks/propertyselector.html
  

GitHub

• Get antcontrib.jar https://github.com/dveselka/java-tutorial/blob/master/tools/pom.xml
  
• ant file to produce sed commands from property file https://github.com/dveselka/java-tutorial/blob/master/tools/build.xml
   

Install antcontrib 

Get via Maven  https://github.com/dveselka/java-tutorial/blob/master/tools/pom.xml

To install ant-contrib:

1. Copy ant-contrib-0.3.jar to the lib directory of your Ant installation. If you want to use one of the tasks in your own project, add the lines

   <taskdef resource="net/sf/antcontrib/antcontrib.properties"/>
   

   to your build file.
2. Keep ant-contrib-0.3.jar in a separate location. You now have to tell Ant explicitly where to find it (say in /usr/share/java/lib):

   <taskdef resource="net/sf/antcontrib/antcontrib.properties">
     <classpath>
       <pathelement location="/usr/share/java/lib/ant-contrib-0.3.jar"/>
     </classpath>
   </taskdef>

 

Get antcontrib.jar via Maven

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>dave</groupId>
    <artifactId>tools</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <parent>
        <groupId>dave</groupId>
        <artifactId>parent</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/ant-contrib/ant-contrib -->
        <dependency>
            <groupId>ant-contrib</groupId>
            <artifactId>ant-contrib</artifactId>
            <version>1.0b3</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-dependency-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${project.build.directory}/lib</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

$ mvn clean install


[INFO] --- maven-dependency-plugin:2.8:copy-dependencies (default) @ tools ---
[INFO] Copying ant-contrib-1.0b3.jar to /git/java-tutorial/tools/target/lib/ant-contrib-1.0b3.jar
[INFO] Copying ant-1.5.jar to /git/java-tutorial/tools/target/lib/ant-1.5.jar

 Properties file https://github.com/dveselka/java-tutorial/blob/master/tools/dave.properties

 a=1
jdbc.url=jdbc:oracle:thin:dave@dave:1521/DAVE_DB
url=https://dave.com/dave
date=Sun Sep 15 08:43:48 AM CEST 2024

 

Build.xml to produce sed file from properties file https://github.com/dveselka/java-tutorial/blob/master/tools/build.xml

Notice that @ gives value of for cycle variable , $ gives value of ant property

<project name="properties-to-sed">

    <taskdef resource="net/sf/antcontrib/antlib.xml">
        <classpath>
            <pathelement location="target/lib/ant-contrib-1.0b3.jar"/>
        </classpath>
    </taskdef>

    <target name="convert">
        
        <property file="dave.properties" prefix="dave."/>
        <propertyselector property="dave" match="dave\.(.*)" select="\1"/>
        
        <for param="key" list="${dave}">
            <sequential>
                <echo>@{key}=${dave.@{key}}</echo>
                <echo message="s#@{key}#${dave.@{key}}#g${line.separator}" file="replace-dave-props.sed" append="true"/>
            </sequential>
        </for>
    </target>
</project>

 

Run ant 

 

 $ ant convert
Buildfile: /git/java-tutorial/tools/build.xml

convert:
     [echo] url=https://dave.com/dave
     [echo] a=1
     [echo] date=Sun Sep 15 08:43:48 AM CEST 2024
     [echo] jdbc.url=jdbc:oracle:thin:dave@dave:1521/DAVE_DB

BUILD SUCCESSFUL
Total time: 0 seconds

Sed file produced from properties file

$ cat replace-dave-props.sed
s#url#https://dave.com/dave#g
s#a#1#g
s#date#Sun Sep 15 08:43:48 AM CEST 2024#g
s#jdbc.url#jdbc:oracle:thin:dave@dave:1521/DAVE_DB#g

 

 Asking Gemimi for hints - useful, provided idea with antcontrib for cycle, needs fixing - add antcontrib install, fix for cycle

 

Approach:

1. Create a build.xml file:

   • Write the Ant build script in a build.xml file.
   • Define a target to perform the conversion.

2. Load properties file:

   • Use the property task to load the properties file.

3. Generate sed commands:

   • Use the for task to iterate over the properties entries.
   • For each entry, create a sed command using the echo task.

4. Write sed commands to file:

   • Use the echo task to write the generated sed commands to a file.

build.xml example:

XML

<project name="properties-to-sed">
    <target name="convert">
        <property file="replacements.properties"/>

        <for param="key" elements="${replacements.keys()}">
            <sequential>
                <echo message="s/${replacements.${key}}/${replacements.${key}}/g" file="sed_script.sed" append="true"/>
            </sequential>
        </for>
    </target>
</project>

Use code with caution.

Explanation:

• The replacements.properties file should contain key-value pairs where the key is the search pattern and the value is the replacement string. For example:

search1=replacement1
search2=replacement2

• The build.xml file defines a convert target.
• The property task loads the properties file.
• The for task iterates over the keys in the properties file.
• For each key, an echo task creates a sed command using the key and value as the search pattern and replacement string.
• The echo task writes the sed command to the sed_script.sed file, appending it to the end of the file.

Additional considerations:

• You can customize the sed command format based on your specific requirements.
• If you need to escape special characters in the search patterns or replacement strings, use appropriate escape sequences.
• For more complex scenarios or performance optimization, consider using a dedicated scripting language like Python or Perl.

 Asking ChatGPT for comparison

Daniel Veselka

convert properties file to sed commands using antcontrib for cycle

ChatGPT

To convert a properties file to sed commands using ant-contrib's for loop functionality, you'll need to follow a similar approach as previously mentioned, with some adjustments to implement the loop correctly. Below, I’ll provide a complete and detailed example, including how to set up your environment to use ant-contrib for iterating through properties.

Example Properties File

Assuming you have a properties file named config.properties:

properties

# config.properties
app.name=MyApp
app.version=1.0.0
app.author=John Doe

Ant Build File

<project name="PropertiesToSed" default="convert" basedir=".">
    
    <property file="config.properties"/>
    
    <target name="convert">
        <echo message="Converting properties to sed commands..." />

        <!-- Loop through the properties defined in config.properties -->
        <property name="properties.list" value="app.name,app.version,app.author"/>

        <foreach list="${properties.list}" param="property">
            <sequential>
                <echo message="sed -i 's/${property}=.*/${property}=${property}:${property}/g' target_file.txt" />
            </sequential>
        </foreach>
        
    </target>
    
</project>

Explanation of the Ant Build File

1. Task Definition for Ant-Contrib: The line <taskdef resource="antcontrib.properties" /> defines the ant-contrib functions so you can use them in your Ant script. Make sure you have the ant-contrib.jar in your Ant classpath.

2. Loading Properties: The properties file is loaded into the project with <property file="config.properties"/>.

3. Defining Properties List: A property properties.list is defined, listing all the keys in the properties file that you want to generate sed commands for.

4. Using <for> Loop: The <for> loop is used to iterate over the properties list. Each property will be accessible via the variable ${property} in the loop.

5. Generating sed Commands:

   • The echo command inside the loop outputs the sed command that will perform the desired replacement in target_file.txt.
   • If you want to replace the value of each property in the file, you can use ${property} to get the key and ${property.value} to retrieve the corresponding value.

Step to Execute the Ant Script

1. Ensure you have ant-contrib: Download the ant-contrib.jar and place it in the lib directory of your Ant installation or add it to your classpath.

2. Run the Ant command:

bash

ant convert

Final Notes

• The generated sed command will replace the line in target_file.txt that matches the pattern property=, updating it with the value from config.properties.
• Adjust the target_file.txt with your actual target file; this is the file where the properties should be replaced.
• Remember that you can customize the sed command based on how you want to implement the replacements based on your specific requirements.