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.
(package private) int	ixData Idf >=0 then the data should be accessed simple from a given List or array with this index.
private boolean	operation_ true then an operation call, false: a variable access.
(package private) java.lang.reflect.Member	reflAccess If set the source class is already .
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)
	DatapathElement(StringPartScan path, java.util.Map<java.lang.String,DataAccess.IntegerIx> nameVariables, java.lang.Class<?> reflData, boolean bFirst) Creates a datapath element. see set(String) also for details of the arguments.

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, boolean bFirst) Creates the first datapath element, which can also access to the variable pool and a reflData class or create further elements but supports the first element for operations arguments.
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	writeAccessString(java.lang.Appendable wr) Writes a String which should show the originally text given access.
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
• '&'; indirect path
• '(': 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.

reflAccess

java.lang.reflect.Member reflAccess

If set the source class is already . To access the value use it.

ixData

int ixData

Idf >=0 then the data should be accessed simple from a given List or array with this index. Not using reflection.

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:

descr - 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,
                       boolean bFirst)
                throws java.text.ParseException

Creates a datapath element. see set(String) also for details of the arguments.

Parameters:

path -

nameVariables - association between name and index. This will be enhanced with not stored variables on the fly.

reflData -

bFirst -

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) The nameVariables will be completed by unknown but necessary variables. On execution then all variables are known.

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,
                boolean bFirst)
         throws java.text.ParseException

Creates the first datapath element, which can also access to the variable pool and a reflData class or create further elements but supports the first element for operations arguments.
The path is parsed and some parts are recognized:

• If bFirst then some start character are recognized, stored in whatisit.
• The identifier is parsed, an identifier should be given. Stored in ident
• If (...) follows, then then whatisit is marked as '(' for an non static operation or remains '% for a static operation. operation_ = true. The arguemnts are parsed, stored in args.
• If [...] follows, indices are parsed as constant values, stored in indices

With this information the access can be done.
For the first element (bFirst argument is set), the following is done:

• If the sp starts with the following special chars "$@%+", it is an element with that whatisit.
• If the sp starts with an identifier, is not an operation, then it is checked, wether the identfier is found in the nameVariables. If true, then ixData is set and whatisit = '@'. ident() = the parsed indetifier.
  indices may be set, as access to array elements in the variable. All other elements are null and false. This is a simple access to a variable.
• If the identifier is not found in the variables, but the argument reflData == null, then the identifier is added to the nameVariables as new variable on demand. This is sensible because without reflData it is an variable. If the variable name is faulty in the application, later a faulty value (variable was not set) will be resulting, so that the error will be found.
• If the identifier is not found, it is not an operation(...), but reflData are given as argument, then the identifier is searched as Field in the reflData. If found, reflAccess is set to use on access.
• If the sp contains a operation(arg, ...) then it is marked as Operation call. If the operation name is found unique in the given reflData, then reflAccess is set with this operation, so the access can use it. If the operation is not found or it is not unique (overridden arguments), then the reflAccess is not set, the operation should be searched on access with the current data.
• 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 - It is used to parse this one element from the whole datapath. After this operation the current position is the position after. It means either a '.' for a next element of the following stuff after the path.

nameVariables - If bFirst is set, it is primary checked whether the path element will be found there. Then ixData is set to access the correct element in varValues, last argument of DataAccess.access(Object, boolean, boolean, Map, Object[]) see DataAccess.DataAccess(StringPartScan, Map, Class, char)

reflData - If bFirst is set, it is secondary checked whether the path element will be found there.

bFirst - ==true for the first element. It can be start with a member of nameVariables or in reflData. if bFirst== false, nameVariables and refldata are not used for this element, but they are necessary for arguments of an operation call.

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 The nameVariables will be completed by unknown but necessary variables. On execution then all variables are known.

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

writeAccessString

public void writeAccessString(java.lang.Appendable wr)
                       throws java.io.IOException

Writes a String which should show the originally text given access. It uses only CalculatorExpr.Operand.textOrVar for the textual representation of the arguments, because this field should store the originally used textual input.

Parameters:

wr - to output

Throws:

java.io.IOException

toString

public java.lang.String toString()

For debugging.

Overrides:

toString in class java.lang.Object