org.vishia.util

Class DataAccess.DatapathElement

java.lang.Object

org.vishia.util.DataAccess.DatapathElement

Direct Known Subclasses:

DataAccess.DatapathElementClass, DataAccess.SetDatapathElement

Enclosing class:

DataAccess

public static class DataAccess.DatapathElement
extends java.lang.Object

Class holds one element for access to data. Instances of this class can be created using ZbnfJavaOutput to fill from a parse result. Therefore some methods have a special naming which matches to the semantic of the used parser script.

Meaning and using of the fnArgs and indices:
Both should be set before DataAccess#access(Object, boolean, boolean) or DataAccess#access(DatapathElement, Object, boolean, boolean, boolean, Dst) is called. The calculation of the arguments and indices should be done outside of the class before usage with adequate operations. To set the results setActualArgumentArray(Object[]) or setActualArguments(Object...) should be used.

set(String): Textual parsing of the path. Its capability was enhanced in 2019-06: Before, the usage of DataAccess was usually related to the ZBNF parser and the JZtxtcmd, which uses the derived class DataAccess.SetDatapathElement and the set_ident(String) etc. from the parse result. The other possibility, set the path immediately only from a given text, was necessary with the OutTextPreparer and it may be proper from user level. That possibility supports only simple argument names stored in #argNames, String literal arguments stored immediately in fnArgs and numeric literal indices stored in indices

Field Summary

Fields

Modifier and Type	Field and Description
private CalculatorExpr.Operand[]	args It is is a method call, contains the argument calculation rules.
protected java.lang.Object[]	fnArgs Deprecated. because it is a violation of the principle that this class stores only data of construction or set, not for current access. It is used yet (2019-08) especially in JZtxtcmdExecuter.
protected java.lang.String	ident Name of the element or method in any instance.
(package private) int[]	indices Numerical values to access elements of the given variable.
private boolean	operation_ true then an operation call, false: a variable access.
protected char	whatisit Kind of element '$': An environment variable.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DatapathElement() Creates an empty element.
	DatapathElement(java.lang.String path) Creates a datapath element.
	DatapathElement(StringPartScan path, java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables, java.lang.Class<?> reflData) Creates a datapath element. see set(String)

Method Summary

Modifier and Type	Method and Description
java.lang.String	argName(int ix) Returns the name for the argument start variable.
java.lang.String	ident()
boolean	isOperation()
int	nrArgNames()
(package private) CalculatorExpr.Operand[]	parseArgumentExpr(StringPartScan sArgs, java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables, java.lang.Class<?> reflData) Parses an argument String with expressions
void	set_ident(java.lang.String text)
void	set_operation() Invoked from ZbnfJavaOutput or other via reflection.
void	set_operation(boolean val) Invoked from ZbnfJavaOutput or other via reflection.
void	set_whatisit(java.lang.String text)
void	set(java.lang.String path) Creates a datapath element, for general purpose.
void	set(StringPartScan path, java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables, java.lang.Class<?> reflData) Creates a datapath element, for general purpose.
void	setActualArgumentArray(java.lang.Object[] args) Adds any argument with its value.
void	setActualArguments(java.lang.Object... args) Adds any argument with its value.
void	setIdent(java.lang.String ident)
java.lang.String	toString() For debugging.
void	writeStruct(java.lang.Appendable out)

Methods inherited from class java.lang.Object

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

Field Detail

ident

protected java.lang.String ident

Name of the element or method in any instance. From Zbnf <$?ident>

whatisit

protected char whatisit

Kind of element

• '$': An environment variable.
• '@': A variable from the additional data pool.
• '.': a field with ident as name.
• '+': new ident, creation of instance maybe with or without arguments in fnArgs
• '%'; call of a static routine maybe with or without arguments in fnArgs
• '(': subroutine maybe with or without arguments in fnArgs.
• 'A': A new Appendable variable
• 'C': A new Class variable
• 'E': A new environment variable
• 'K': A new Value variable
• 'L': A new list container.
• 'O': A new Object variable
• 'P': A new pipe variable.
• 'Q': A new Boolean variable
• 'S': A new String variable
• 'X': A new Codeblock variable (eXecute, Subtextvar, Subroutinevar)

A new Variable should be stored newly as DataAccess.Variable with that given type using DataAccess#storeValue(List, Map, Object, boolean).

fnArgs

@Deprecated
protected java.lang.Object[] fnArgs

Deprecated. because it is a violation of the principle that this class stores only data of construction or set, not for current access. It is used yet (2019-08) especially in JZtxtcmdExecuter.

List of actual arguments of a method. If null, it is not a method or the method has not arguments or the arguments should be prepared in DataAccess.invokeMethod(DatapathElement, Class, Object, boolean, Object[], boolean).

args

private CalculatorExpr.Operand[] args

It is is a method call, contains the argument calculation rules. The CalculatorExpr.Operand.textOrVar contains the name of the start variable if given.

indices

int[] indices

Numerical values to access elements of the given variable. More as one for multi-dimensional element. TODO replace it by using args maybe with const values.

operation_

private boolean operation_

true then an operation call, false: a variable access. @since 2018-08

Constructor Detail

DatapathElement

protected DatapathElement()

Creates an empty element.

DatapathElement

public DatapathElement(java.lang.String path)
                throws java.text.ParseException

Creates a datapath element.

Parameters:

name - see set(String)

Throws:

java.text.ParseException

DatapathElement

public DatapathElement(StringPartScan path,
                       java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables,
                       java.lang.Class<?> reflData)
                throws java.text.ParseException

Creates a datapath element. see set(String)

Parameters:

path -

nameVariables - see DataAccess.DataAccess(StringPartScan, Map, Class, char)

reflData - see DataAccess.DataAccess(StringPartScan, Map, Class, char)

Throws:

java.text.ParseException

Method Detail

set_operation

public void set_operation(boolean val)

Invoked from ZbnfJavaOutput or other via reflection.

set_operation

public void set_operation()

Invoked from ZbnfJavaOutput or other via reflection.

isOperation

public boolean isOperation()

nrArgNames

public int nrArgNames()

argName

public java.lang.String argName(int ix)

Returns the name for the argument start variable. It helps to fill the set the varValues on call of DataAccess.invokeMethod(DatapathElement, Class, Object, boolean, Object[], boolean)

set

public void set(java.lang.String path)
         throws java.text.ParseException

Creates a datapath element, for general purpose. If the name starts with the following special chars "$@%+", it is an element with that whatisit. If the name contains a '(' it is a method call. Elsewhere it is the name of a field. If it is a method call, the following rules are taken for evaluating parameters:

• Argument in "": a constant string
• Argument able to convert to a numeric value: The numeric value
• Argument starts with '*': A data path
• Elsewhere use CalculatorExpr.setExpr(String).

Parameters:

path -

Throws:

java.text.ParseException

set

public void set(StringPartScan path,
                java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables,
                java.lang.Class<?> reflData)
         throws java.text.ParseException

Creates a datapath element, for general purpose.

• If the sp starts with the following special chars "$@%+", it is an element with that whatisit.
• if the sp contains a operation(arg, ...) then it is marked as Operation call. The args are yet only names, TODO it should be expression (including constants etc.).
• If the sp contains array[indices] the index values are parsed with CalculatorExpr#setExpr(StringPartScan). Usual they are only integer literal constants, then the value is stored immediately.

Parameters:

path -

nameVariables - see DataAccess.DataAccess(StringPartScan, Map, Class, char)

reflData - see DataAccess.DataAccess(StringPartScan, Map, Class, char)

Throws:

java.text.ParseException

parseArgumentExpr

CalculatorExpr.Operand[] parseArgumentExpr(StringPartScan sArgs,
                                           java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables,
                                           java.lang.Class<?> reflData)
                                    throws java.text.ParseException

Parses an argument String with expressions

Parameters:

sArgs - The starting "(" is parsed already, by previous check. A following ")" is not read. It means the sArgs can contain the argument String without (). After parsing the sArgs is set before ")" if exist, after the args. The Syntax of any arg is determined by functionality of CalculatorExpr#CalculatorExpr(StringPartScan, Map, Class).

nameVariables - Map of variables

reflData -

Returns:

Throws:

java.text.ParseException

set_ident

public void set_ident(java.lang.String text)

set_whatisit

public void set_whatisit(java.lang.String text)

ident

public java.lang.String ident()

setIdent

public void setIdent(java.lang.String ident)

setActualArguments

public void setActualArguments(java.lang.Object... args)

Adds any argument with its value.

setActualArgumentArray

public void setActualArgumentArray(java.lang.Object[] args)

Adds any argument with its value.

writeStruct

public void writeStruct(java.lang.Appendable out)
                 throws java.io.IOException

Throws:

java.io.IOException

toString

public java.lang.String toString()

For debugging.

Overrides:

toString in class java.lang.Object