Class IncrementalBuildHelper


  • public class IncrementalBuildHelper
    extends java.lang.Object
    Various helper methods to support incremental builds
    • Field Detail

      • MAVEN_STATUS_ROOT

        private static final java.lang.String MAVEN_STATUS_ROOT
        the root directory to store status information about Maven executions in.
        See Also:
        Constant Field Values
      • CREATED_FILES_LST_FILENAME

        public static final java.lang.String CREATED_FILES_LST_FILENAME
        See Also:
        Constant Field Values
      • INPUT_FILES_LST_FILENAME

        private static final java.lang.String INPUT_FILES_LST_FILENAME
        See Also:
        Constant Field Values
      • EMPTY_ARRAY

        private static final java.lang.String[] EMPTY_ARRAY
      • mojoExecution

        private org.apache.maven.plugin.MojoExecution mojoExecution
        Needed for storing the status for the incremental build support.
      • mavenProject

        private org.apache.maven.project.MavenProject mavenProject
        Needed for storing the status for the incremental build support.
      • directoryScanner

        private org.apache.maven.shared.utils.io.DirectoryScanner directoryScanner
        Used for detecting changes between the Mojo execution.
    • Constructor Detail

      • IncrementalBuildHelper

        public IncrementalBuildHelper​(org.apache.maven.plugin.MojoExecution mojoExecution,
                                      org.apache.maven.execution.MavenSession mavenSession)
      • IncrementalBuildHelper

        public IncrementalBuildHelper​(org.apache.maven.plugin.MojoExecution mojoExecution,
                                      org.apache.maven.project.MavenProject mavenProject)
    • Method Detail

      • getMavenProject

        private static org.apache.maven.project.MavenProject getMavenProject​(org.apache.maven.execution.MavenSession mavenSession)
        small helper method to allow for the nullcheck in the ct invocation
      • getDirectoryScanner

        public org.apache.maven.shared.utils.io.DirectoryScanner getDirectoryScanner()
        Get the existing DirectoryScanner used by this helper, or create new a DirectoryScanner if none is yet set. The DirectoryScanner is used for detecting changes in a directory
      • setDirectoryScanner

        public void setDirectoryScanner​(org.apache.maven.shared.utils.io.DirectoryScanner directoryScanner)
        Set the DirectoryScanner which shall get used by this build helper.
        Parameters:
        directoryScanner -
      • getMojoStatusDirectory

        public java.io.File getMojoStatusDirectory()
                                            throws org.apache.maven.plugin.MojoExecutionException
        We use a specific status directory for each Mojo execution to store state which is needed during the next build invocation run.
        Returns:
        the directory for storing status information of the current Mojo execution.
        Throws:
        org.apache.maven.plugin.MojoExecutionException
      • inputFileTreeChanged

        public boolean inputFileTreeChanged​(IncrementalBuildHelperRequest incrementalBuildHelperRequest)
                                     throws org.apache.maven.plugin.MojoExecutionException
        Detect whether the list of detected files has changed since the last build. We simply load the list of files for the previous build from a status file and compare it with the new list. Afterwards we store the new list in the status file.
        Parameters:
        incrementalBuildHelperRequest -
        Returns:
        true if the set of inputFiles got changed since the last build.
        Throws:
        org.apache.maven.plugin.MojoExecutionException
      • inputFileTreeChanged

        public boolean inputFileTreeChanged​(org.apache.maven.shared.utils.io.DirectoryScanner dirScanner)
                                     throws org.apache.maven.plugin.MojoExecutionException
        Detect whether the list of detected files picked up by the DirectoryScanner has changed since the last build. We simply load the list of files for the previous build from a status file and compare it with the result of the new DirectoryScanner#scan(). Afterwards we store the new list in the status file.
        Parameters:
        dirScanner -
        Returns:
        true if the set of inputFiles got changed since the last build.
        Throws:
        org.apache.maven.plugin.MojoExecutionException
      • beforeRebuildExecution

        public java.lang.String[] beforeRebuildExecution​(IncrementalBuildHelperRequest incrementalBuildHelperRequest)
                                                  throws org.apache.maven.plugin.MojoExecutionException

        This method shall get invoked before the actual Mojo task gets triggered, e.g. the actual compile in maven-compiler-plugin.

        Attention: This method shall only get invoked if the plugin re-creates all the output.

        It first picks up the list of files created in the previous build and delete them. This step is necessary to prevent left-overs. After that we take a 'directory snapshot' (list of all files which exist in the outputDirectory after the clean).

        After the actual Mojo task got executed you should invoke the method afterRebuildExecution(org.apache.maven.shared.incremental.IncrementalBuildHelperRequest) to collect the list of files which got changed by this task.

        Parameters:
        incrementalBuildHelperRequest -
        Returns:
        all files which got created in the previous build and have been deleted now.
        Throws:
        org.apache.maven.plugin.MojoExecutionException
      • afterRebuildExecution

        public void afterRebuildExecution​(IncrementalBuildHelperRequest incrementalBuildHelperRequest)
                                   throws org.apache.maven.plugin.MojoExecutionException

        This method collects and stores all information about files changed since the call to beforeRebuildExecution(org.apache.maven.shared.incremental.IncrementalBuildHelperRequest).

        Attention: This method shall only get invoked if the plugin re-creates all the output.

        Parameters:
        incrementalBuildHelperRequest - will contains file sources to store if create files are not yet stored
        Throws:
        org.apache.maven.plugin.MojoExecutionException
      • toArrayOfPath

        private java.lang.String[] toArrayOfPath​(java.util.Set<java.io.File> files)