I am reading a file in ant and loading the properties through loadproperties. I am interested in using the value of a specific property, whose name is not known. I know that it follows a pattern because that is how I load the property.
I can echoproperties and see that it is being loaded.
But I dont know how to access its value, given that its name is actually a pattern rather that hardcoded.
How can I access this property's value to do some processing.
I hope this is clear. Please ask if I need to clarify some more.
Take a look at ant-contrib package. Its propertycopy task will do what you need. If you need to resolve an arbitrary number of properties following an established pattern, you would use ant-contrib's propertycopy in conjunction with ant-contribs "for" task.
http://ant-contrib.sourceforge.net/tasks/tasks/index.html
You should use Ant's script task.
I suggest using the beanshell script since it is pure java.
For example, to print all properties for your project, use the following:
<target name="echoprops">
<script language="beanshell">
System.out.println("All Properties: " + project.getProperties().keySet());
</script>
</target>
It should be easy to modify the above script to get the property you want.
To use this task, you will need to run the following in $ANT_HOME first:
ant -f fetch.xml script -Ddest=user
That will download all required optional jars to ~/.ant/lib .
Related
I have an Ant buildfile (build.xml) which is called by some application. I would like to know exactly what kind of properties are used to invoke Ant. Therefore I would like to modify the build.xml file to display all properties specified in the call, e.g.:
ant aTarget -Dxslt.parser=SAXON -Dbasedir=aFolder
would display list as below
- target: aTarget
- xslt.parser = SAXON
- basedir=aFolder
Please note that I do not know exactly what is being using to invoke Ant. Therefore, I need to use some sort of a loop get all properties, options.
The simplest thing that comes to mind is to place a line like:
<echo message="Ant invocation is '${sun.java.command}'" />
In the buildfile outside of any target. It'll look something like:
% ant aTarget -Dx=y
[echo] ant invocation is: 'org.apache.tools.ant.launch.Launcher -cp . aTarget -Dx=y'
It shows you what was passed to the Ant Launcher, which might will likely be a little more than what was passed to the ant wrapper script, but should do.
I would avoid trying to parse the line, as you say, you don't know what might be there, and it could quickly get complicated.
Take a look at the <echoproperties> task:
<property name="in.file.prop" value="value2"/>
<echoproperties/>
in.file.prop and its value will be printed. However, over 60 other properties will be printed as well including properties built into Ant.
You can save the results of <echoproperties> to a file and then filter that file with something like a <linecontains> filter.
I have an ant script which has a taskdef and the task creates an https internet connection and somethin with that SSL stuff is wrong. Thus I want to set the system property javax.net.debug=all to get some more information.
In java I would do this using the -D option, but in ant this is used for ant properties which is not the same as a system property.
If this wouldn't be a taskdef but instead a java task, I could use the sysproperty property, but it is no java-task.
Googling for this is frustratingly complicated because ant properties and system properties in ant are so similar that most search results are about the other (or about the java-task).
Obviously I am not the only one with the problem, but other people's questions that I have found (like here) are unanswered or went for hack (like here).
One way to set such a property is the ANT_OPTS system variable. You have to be very carefully to not simply skim over answers on google that state that options can be set that way, because it sounds so much like not what it does:
The documentation says:
ANT_OPTS - command-line arguments that should be passed to the JVM.
For example, you can define system properties or set the maximum Java
heap size here.
Who what have expected that? ANT_OPTS are options for the JVM and not for ant like the name suggests. The var which is used for ant options is called ANT_ARGS.
Now I can launch ant like this: ANT_OPTS="-Djavax.net.debug=all" ant myTarget and can see tons of log output.
(However this leaves the question open whether such a variable can be set using XML).
You can declare system properties in the xml with <sysproperty key="key" value="value"/>.
http://www.java2s.com/Code/Java/Ant/SetsystempropertiesinAntbuildscript.htm
You can use scripting:
<script language="javascript">
java.lang.System.setProperty('myKey', 'myValue');
</script>
I want to know if it is possible to get an ant script to reference 2 different .properties files at once, and if so, how to accomplish this.
Assume that the properties contained within the two .properties files are mutually exclusive, i.e. the same property will not appear twice.
Thanks!
In addition to Ash answer.
You can use a different prefix attribute of property task, e.g
<property file="file1.properties" prefix="file1"/>
<property file="file2.properties" prefix="file2"/>
This way you can find out if both files have same properties and differentiate between them in your build script. For example if both files have property test, then after they are loaded with the above commands you will end up with properties named file1.test and file2.test.
You should be able to import any number of properties files with multiple <property file="..."> entries in your ant script (unless there's some subtlety to your question that I've missed?). Duplicate properties are OK, since in ant properties are immutable and whoever sets the property first "wins".
See http://ant.apache.org/manual/Tasks/property.html for more details.
I need to modify a (xml-)file from Apache Ant. "loadfile" task allows to load the file's content in a property. But how to store the property's value back to a file after its (property) modification?
Of course I could write custom task to perform this operation but I would like to know if there's some existing implementation.
You can use the echo task.
<echo file="${fileName}" message="${xmlProperty}"/>
The echoxml task might be of interest to you as well.
Use propertyfile task. An example taken from ant manual:
<propertyfile file="my.properties">
<entry key="abc" value="${abc}"/>
</propertyfile>
This may be better than echo as it updates the properties file with a given value, while echo appends to or overwrites the whole file.
What's the difference between #{property} and ${property} in accessing Ant properties?
Didn't see any obvious note about it in the Ant manual.
${property} is the normal way to access properties. #{property} is used inside macro definitions to access arguments passed to this macro. See the Ant manual on macrodef.
${property} is used to reference Properties.
#{attribute} is used to reference Attributes in <macrodef> Tasks.