Package io.jawk.ext

Class AbstractExtension

java.lang.Object

io.jawk.ext.AbstractExtension

All Implemented Interfaces:

JawkExtension

Direct Known Subclasses:

GawkExtension, StdinExtension

public abstract class AbstractExtension
extends Object
implements JawkExtension

Base class of various extensions.

Provides functionality common to most extensions, such as VM and JRT variable management, and convenience methods such as checkNumArgs() and toAwkString().

Author:

Danny Daglas

Constructor Summary

Constructors

Constructor	Description
AbstractExtension()

Method Summary

Modifier and Type	Method	Description
void	beforeStart(AVM avm, JRT runtime)	Called after the runtime global variable slots have been allocated and before the first executable tuple runs.
protected static void	checkNumArgs(Object[] arr, int expectedNum)	Verifies that an exact number of arguments has been passed in by checking the length of the argument array.
Map<String,ExtensionFunction>	getExtensionFunctions()	Returns the mapping between Awk keywords and the functions implemented by this extension.
String	getExtensionName()	getExtensionName.
protected JRT	getJrt()	Getter for the field jrt.
protected AwkSettings	getSettings()	Getter for the field settings.
protected VariableManager	getVm()	Getter for the field vm.
void	init(VariableManager vmParam, JRT runtime, AwkSettings conf)	Called after the creation and before normal processing of the extension, pass in the Jawk Runtime Manager and the Variable Manager once.
protected final String	toAwkString(Object obj)	Convert a Jawk variable to a Jawk string based on the value of the CONVFMT variable.

Methods inherited from class java.lang.Object

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

Constructor Details

AbstractExtension

public AbstractExtension()

Method Details

getExtensionName

public String getExtensionName()

getExtensionName.

Specified by:

getExtensionName in interface JawkExtension

Returns:

name of the extension package.

init

public void init(VariableManager vmParam,
 JRT runtime,
 AwkSettings conf)

Called after the creation and before normal processing of the extension, pass in the Jawk Runtime Manager and the Variable Manager once.

It is guaranteed init() is called before invoke() is called.

Specified by:

init in interface JawkExtension

Parameters:

vmParam - Reference to the Variable Manager

runtime - Reference to the Runtime

conf - Reference to the settings

toAwkString

protected final String toAwkString(Object obj)

Convert a Jawk variable to a Jawk string based on the value of the CONVFMT variable.

Parameters:

obj - The Jawk variable to convert to a Jawk string.

Returns:

A string representation of obj after CONVFMT has been applied.

checkNumArgs

protected static void checkNumArgs(Object[] arr,
 int expectedNum)

Verifies that an exact number of arguments has been passed in by checking the length of the argument array.

Parameters:

arr - The arguments to check.

expectedNum - The expected number of arguments.

getJrt

protected JRT getJrt()

Getter for the field jrt.

Returns:

the Runtime

getVm

protected VariableManager getVm()

Getter for the field vm.

Returns:

the Variable Manager

getSettings

protected AwkSettings getSettings()

Getter for the field settings.

Returns:

the Settings

getExtensionFunctions

public Map<String,ExtensionFunction> getExtensionFunctions()

Returns the mapping between Awk keywords and the functions implemented by this extension. The returned map must be unmodifiable.

Specified by:

getExtensionFunctions in interface JawkExtension

Returns:

mapping from keyword to ExtensionFunction

beforeStart

public void beforeStart(AVM avm,
 JRT runtime)

Called after the runtime global variable slots have been allocated and before the first executable tuple runs.

Specified by:

beforeStart in interface JawkExtension

Parameters:

avm - interpreter instance about to execute the tuple stream

runtime - runtime services associated with avm