Let *download-licenses store the name of the downloaded file in licenses.xml

[ppalaga]

We create an HTML report out of licenses.xml where we are adding a link to the downloaded license file. It is currently impossible to reliably figure what the downloaded file name is. Thus I am proposing the following:

1. There will be a new <file> element under <license> in licenses.xml.

2. <file> would be written into licenses.xml by the AbstractDownloadLicensesMojo.

Any reason why I should not send a patch?

[ppalaga]

Patch available in #157

[k-wall]

Testing on master. I think I am seeing a regression caused by this change. If the license.xml exists but includes a reference to a license that previously failed to download (a 404 in my case), a second Maven invocation reports the following NPE.

I attach a license.xml.

licenses.xml.zip

I can see the failing case is from https://glassfish.java.net/public/CDDL+GPL_1_1.html (which gives a 404).

The XML stored for it lacks a <file> element.

 <license>
          <name>CDDL/GPLv2+CE</name>
          <url>https://glassfish.java.net/public/CDDL+GPL_1_1.html</url>
          <distribution>repo</distribution>
          <comments>CDDL or GPL version 2 plus the Classpath Exception</comments>
</license>

[ERROR] Failed to execute goal org.codehaus.mojo:license-maven-plugin:1.17-SNAPSHOT:download-licenses (download-thirdparty-licenses) on project keycloak-controller: Unable to parse license summary output file: /Users/keith/src/enmasse/keycloak-controller/target/classes/licenses/licenses.xml: NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:license-maven-plugin:1.17-SNAPSHOT:download-licenses (download-thirdparty-licenses) on project keycloak-controller: Unable to parse license summary output file: /Users/keith/src/enmasse/keycloak-controller/target/classes/licenses/licenses.xml
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:213)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:993)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:345)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:191)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Unable to parse license summary output file: /Users/keith/src/enmasse/keycloak-controller/target/classes/licenses/licenses.xml
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.loadLicenseInfo(AbstractDownloadLicensesMojo.java:597)
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.execute(AbstractDownloadLicensesMojo.java:334)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
	... 20 more
Caused by: java.lang.NullPointerException
	at java.io.File.<init>(File.java:360)
	at org.codehaus.mojo.license.AbstractDownloadLicensesMojo.loadLicenseInfo(AbstractDownloadLicensesMojo.java:590)
	... 23 more
[ERROR]
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException