org.rhq.core.pluginapi.util

Class JavaCommandLine

java.lang.Object

org.rhq.core.pluginapi.util.JavaCommandLine

public class JavaCommandLine
extends Object

Parses a java command line and provides easy access to its parts.

A Java command line looks like this:

   Usage: java [-options] class [args...]
         (to execute a class)
      or  java [-options] -jar jarfile [args...]
         (to execute a jar file)
 

Note that this class offers the subclasses to ehance the parsing process by overriding the processClassArgument(String, String) method. To be able to achieve that, the evaluation of the commandline arguments needs to happen lazily. See the parseCommandLine() method for subclassing guidelines.

This class is NOT thread-safe.

Author:

Ian Springer, Lukas Krejci

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JavaCommandLine.OptionValueDelimiter When parsing command line options, specifies the valid option value delimiter(s).

Constructor Summary

Constructors

Constructor and Description
JavaCommandLine(String... args) Same as JavaCommandLine(args, false, OptionFormat.POSIX, OptionFormat.POSIX)
JavaCommandLine(String[] args, boolean includeSystemPropertiesFromClassArguments) Same as JavaCommandLine(args, includeSystemPropertiesFromClassArguments, OptionFormat.POSIX, OptionFormat.POSIX)
JavaCommandLine(String[] args, boolean includeSystemPropertiesFromClassArguments, Set<JavaCommandLine.OptionValueDelimiter> shortClassOptionValueDelims, Set<JavaCommandLine.OptionValueDelimiter> longClassOptionValueDelims)

Method Summary

Methods

Modifier and Type	Method and Description
List<String>	getArguments()
List<String>	getClassArguments()
String	getClassOption(CommandLineOption option)
String	getClassOption(CommandLineOption option, String defaultValue)
List<String>	getClassPath()
File	getExecutableJarFile()
File	getJavaExecutable()
List<String>	getJavaOptions()
String	getMainClassName()
Map<String,String>	getSystemProperties()
protected boolean	isArgumentsParsed()
boolean	isClassOptionPresent(CommandLineOption option)
protected void	parseCommandLine() This method can be called to process the command line from the arguments passed in the constructor.
protected void	processClassArgument(String classArg, String nextArg) Override this method to do additional processing of the class arguments.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

JavaCommandLine

public JavaCommandLine(String... args)

Same as JavaCommandLine(args, false, OptionFormat.POSIX, OptionFormat.POSIX)

JavaCommandLine

public JavaCommandLine(String[] args,
               boolean includeSystemPropertiesFromClassArguments)

Same as JavaCommandLine(args, includeSystemPropertiesFromClassArguments, OptionFormat.POSIX, OptionFormat.POSIX)

JavaCommandLine

public JavaCommandLine(String[] args,
               boolean includeSystemPropertiesFromClassArguments,
               Set<JavaCommandLine.OptionValueDelimiter> shortClassOptionValueDelims,
               Set<JavaCommandLine.OptionValueDelimiter> longClassOptionValueDelims)

Method Detail

parseCommandLine

protected void parseCommandLine()

This method can be called to process the command line from the arguments passed in the constructor. This is to support lazy evaluation of the parsed properties.

Any class overriding the processClassArgument(String, String) method should make sure to call this method if it finds that the data extracted in that method is still uninitialized.

Typically, this will happen during a getter for such data:

 
 public Data getDataExtractedFromCommandLine() {
     if (data == null) {
          parseCommandLine();
     }

     return data;
 }
 
 

The data variable would then be initialized as part of the processClassArgument(String, String) method that gets called during the execution of this method.

Alternatively to the null check on the data, the subclass can use the isArgumentsParsed() method that returns true only if this method successfully finished.

If you are overriding this method make sure to call super.parseCommandLine() before any of your other logic, otherwise you may end up with an endless loop (and eventually stack overflow) if you try to access any of the getters of the data extracted from the commandline (like getClassArguments(), getClassPath(), etc).

isArgumentsParsed

protected boolean isArgumentsParsed()

Returns:

true iff the parseCommandLine() method was called and successfully finished.

processClassArgument

protected void processClassArgument(String classArg,
                        String nextArg)

Override this method to do additional processing of the class arguments. This method is called during the parseCommandLine() call but after all other properties are processed.

It is therefore safe to call getClassArguments(), getExecutableJarFile() and all other getters defined by JavaCommandLine. At the time this method is called during parseCommandLine(), the default implementation of isArgumentsParsed() already returns true.

This method is called at a stage during the parsing of the commandline where all the properties are still writeable - you can modify the system properties and other collections.

By default this method does nothing.

Parameters:

classArg -

nextArg -

getArguments

@NotNull
public List<String> getArguments()

getJavaExecutable

@NotNull
public File getJavaExecutable()

getClassPath

@NotNull
public List<String> getClassPath()

getSystemProperties

@NotNull
public Map<String,String> getSystemProperties()

getJavaOptions

@NotNull
public List<String> getJavaOptions()

getMainClassName

@Nullable
public String getMainClassName()

getExecutableJarFile

@Nullable
public File getExecutableJarFile()

getClassArguments

@NotNull
public List<String> getClassArguments()

getClassOption

@Nullable
public String getClassOption(CommandLineOption option)

Parameters:

option - the class option to look for

Returns:

null if the class option is not on the command line, "" if it is on the command line and either has no value or expects no value, and otherwise the non-empty value.

getClassOption

@Nullable
public String getClassOption(CommandLineOption option,
                             String defaultValue)

Parameters:

option - the class option to look for

defaultValue - the value to return if the specified class option is not on the command line

Returns:

null if the class option is not on the command line, "" if it is on the command line and either has no value or expects no value, and otherwise the non-empty value.

isClassOptionPresent

public boolean isClassOptionPresent(CommandLineOption option)

toString

public String toString()

Overrides:

toString in class Object