Package bm.target

Class FileTarget

java.lang.Object

bm.target.FileTarget

All Implemented Interfaces:

StateProvider, Target

public final class FileTarget
extends Object
implements Target

A target representing the state of a file or all files found in a directory, based on a checksum taken over the file/all files.

Example: to compile a bunch of files in a directory, say src/main/java, the compile target needs a dependency which is, of course, a target too. It is the target which keeps track of whether the source files where changed or not:

 Target javaSource = FileState.ofContent("src/main/java").toFileTarget();
 

This target has no builder since the source files need not be created, we only keep track of whether they were changed by the developer. Now to compile the files into build/classes we define

 Target javaClasses = FileState.ofContent("build/classes")
     .toFileTarget()
     .dependsOn(javaSource)
     .buildWith(target -> compileJava(target, javaSources);
 

Here compileJava is a method you have to write which executes javac to run the compilation.

See also: FileState.toFileTarget(List, ConsumeOrThrow).

Constructor Summary

Constructors

Constructor	Description
FileTarget(FileState state, List<? extends Target> dependencies, ConsumeOrThrow<FileTarget> builder)	Creates an instance.

Method Summary

Modifier and Type	Method	Description
void	addState(Consumer<byte[]> sink)	Given a sink for byte[] this method should provide bytes representing a target's value.
FileTarget	buildWith(ConsumeOrThrow<FileTarget> newBuilder)
FileTarget	dependsOn(Target... newDependencies)
FileTarget	dependsOn(List<? extends Target> newDependencies)
static FileTarget	directoryCreateTarget(Path dir)	Creates a target with a builder to create a directory if it does not exist.
List<Target>	getDependencies()	Return the list of targets this one depends on when being build.
List<Path>	getFiles()	Provides all files in the target's directory or just the file.
List<Path>	getFilesRelative()	Provides all files in the target's directory or just the file.
String	getName()	A file target's name is the name of the target path.
Path	getPath()	Provides the target's path
void	recreate()	Recreate this target.
String	toString()
FileTarget	withName(String newName)	Creates a new instance having the new name.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

FileTarget

public FileTarget(FileState state,
 List<? extends Target> dependencies,
 ConsumeOrThrow<FileTarget> builder)

Creates an instance. The name is taken from the target path of the state provided.

Rather than this constructor consider using FileContentState.fromContent(Path) or FileContentState.fromLastModified(String) and the convert to the target with FileState.toFileTarget().

Parameters:

state - representing this object's path

dependencies - it depends on

builder - to run to re-create the target

Method Details

directoryCreateTarget

public static FileTarget directoryCreateTarget(Path dir)

Creates a target with a builder to create a directory if it does not exist.

Parameters:

dir - to create.

Returns:

the target

dependsOn

public FileTarget dependsOn(Target... newDependencies)

dependsOn

public FileTarget dependsOn(List<? extends Target> newDependencies)

buildWith

public FileTarget buildWith(ConsumeOrThrow<FileTarget> newBuilder)

withName

public FileTarget withName(String newName)

Creates a new instance having the new name.

Parameters:

newName - the new name

Returns:

an instance with the new name and otherwise with the same parameters as this.

getPath

public Path getPath()

Provides the target's path

Returns:

file or directory path as provided in the constructor

getFiles

public List<Path> getFiles()

Provides all files in the target's directory or just the file.

Returns:

file paths

getFilesRelative

public List<Path> getFilesRelative()

Provides all files in the target's directory or just the file.

Returns:

file paths relative to what getPath() returns

getName

public String getName()

A file target's name is the name of the target path.

Specified by:

getName in interface Target

Returns:

the name

getDependencies

public List<Target> getDependencies()

Description copied from interface: Target

Return the list of targets this one depends on when being build. This should list all targets whose change should trigger a rebuild of this target.

Specified by:

getDependencies in interface Target

Returns:

the dependencies of this target

addState

public void addState(Consumer<byte[]> sink)
              throws BuildProblemException

Description copied from interface: StateProvider

Given a sink for byte[] this method should provide bytes representing a target's value. If the value changes, the bytes provided must change too. But the bytes may also change if the value was not actually changed, though this will result in unnecessary builts of a target.

This should not mingle in any dependency data.

As examples consider the full byte content of a file or only its last modified time. The latter changes even if a file is overwritten by itself, but for some cases, i.e. huge files, the time stamp may be preferable.

Specified by:

addState in interface StateProvider

Parameters:

sink - into which to fill the state representing bytes

Throws:

BuildProblemException - as needed

recreate

public void recreate()
              throws BuildProblemException

Description copied from interface: Target

Recreate this target.

Specified by:

recreate in interface Target

Throws:

BuildProblemException - as needed

toString

public String toString()

Overrides:

toString in class Object