com.singularsys.jep
Class PrintVisitor

java.lang.Object
  com.singularsys.jep.PrintVisitor

All Implemented Interfaces:

JepComponent, ParserVisitor, java.io.Serializable

public class PrintVisitor
extends java.lang.Object
implements ParserVisitor, JepComponent

Prints an expression with configuration options.

By default, expressions are printed with only necessary bracketing. For example, if an expression "a+(b+c)" is parsed and printed, it will be printed as a+b+c since the bracketing does not affect the evaluation.

Enabling the FULL_BRACKET mode prints the expression with many brackets as ((-1.0)/sqrt((1.0-(x^2.0)))).

To use the PrintVisitor, you can invoke it through the Jep class as follows:

 Jep j = ...; Node in = ...;
 j.print(in, "x");
 

You can also print expressions independently from the Jep class by using this class and calling the various print methods.

Since:

Dec 04 and NumberFormat object can be supplied to modify printing of numbers., Dec 04 PrintVisitor can now cope with 3 or more arguments to + and *., 3.3 greater customisation now possible

Author:

Rich Morris Created on 20-Jun-2003

See Also:

Jep.print(Node), Jep.print(Node, PrintStream), Jep.println(Node), Jep.println(Node, PrintStream), Jep.toString(Node), Serialized Form

Nested Class Summary

static interface	PrintVisitor.PrintRulesI This interface specifies the method needed to implement a special print rule.
static class	PrintVisitor.StdElePrintRule Prints an list access in form a[3] or for multidimensional access use the list syntax.
static class	PrintVisitor.StdListPrintRule Prints a list of elements using '[' and ']' as delimiters and ',' as a separators.

Field Summary

static int	COMPLEX_I Enable this mode to print complex numbers as 3+2 i
protected java.text.NumberFormat	format The NumberFormat object used to print numbers.
static int	FULL_BRACKET Enable this mode to print all brackets.
protected int	mode The current mode for printing.
protected java.lang.StringBuffer	sb

Constructor Summary

PrintVisitor()
Creates a visitor to create and print string representations of an expression tree.

Method Summary

void	addSpecialRule(Operator op, PrintVisitor.PrintRulesI rule) Adds a special print rule to be added for a given operator.
void	addSpecialRule(java.lang.String funName, PrintVisitor.PrintRulesI rule) Adds a special print rule to be added for a given function.
java.lang.String	addSpecialVarName(java.lang.String oldName, java.lang.String newName) Allows a replacement for a specific variable name
void	append(java.lang.String s) Add a string to buffer.
java.lang.String	formatValue(java.lang.Object val) Returns a formatted version of the value.
void	formatValue(java.lang.Object val, java.lang.StringBuffer sb1) Appends a formatted versions of val to the string buffer.
java.lang.String	getFunArgSep() Get the string separating function arguments.
java.lang.String	getFunLBracket() Get the string for left bracket around function arguments.
java.lang.String	getFunRBracket() Get the string for right bracket around function arguments.
java.lang.String	getLBracket() Get the string for left brackets.
JepComponent	getLightWeightInstance() Gets a light-weight instance suitable for using in multiple threads.
int	getMaxLen()
int	getMode() Return the current print mode.
boolean	getMode(int testmode) Returns true if the specified testmode is active.
java.lang.String	getRBracket() Get the string for right brackets.
void	init(Jep jep) Initialize the component.
void	print(Node node) Prints on System.out.
void	print(Node node, java.io.PrintStream out) Prints the tree descending from node with lots of brackets or specified stream.
void	printBrackets(Node node) Print a node surrounded by brackets.
void	println(Node node) Prints on System.out.
void	println(Node node, java.io.PrintStream out) Prints the tree descending from node with a newline at end.
void	printNoBrackets(Node node) Print the node with no brackets.
void	printWrap(java.lang.StringBuffer sb, java.io.PrintStream out) Utility method to print a wrapped version of the output.
void	setFunArgSep(java.lang.String functionArgSep) Set the string separating function arguments.
void	setFunLBracket(java.lang.String funLBracket) Set the string for left bracket around function arguments.
void	setFunRBracket(java.lang.String funRBracket) Set the string for right bracket around function arguments.
void	setLBracket(java.lang.String bracket) Set the string for left brackets.
void	setMaxLen(int i) Sets the maximum length printed per line.
void	setMode(int mode, boolean flag) Set printing mode.
void	setNumberFormat(java.text.NumberFormat format)
void	setRBracket(java.lang.String bracket) Set the string for right brackets.
java.lang.String	toString(Node node) Returns a String representation of the equation.
java.lang.Object	visit(ASTConstant node, java.lang.Object data)
java.lang.Object	visit(ASTFunNode node, java.lang.Object data) Prints a standard function: fun(arg, arg)
java.lang.Object	visit(ASTOpNode node, java.lang.Object data)
java.lang.Object	visit(ASTVarNode node, java.lang.Object data)

Methods inherited from class java.lang.Object

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

Field Detail

FULL_BRACKET

public static final int FULL_BRACKET

Enable this mode to print all brackets. Removes all ambiguity.

See Also:

Constant Field Values

COMPLEX_I

public static final int COMPLEX_I

Enable this mode to print complex numbers as 3+2 i

See Also:

Constant Field Values

sb

protected transient java.lang.StringBuffer sb

mode

protected int mode

The current mode for printing. Stores multiple flags as a bit field.

format

protected java.text.NumberFormat format

The NumberFormat object used to print numbers.

Constructor Detail

PrintVisitor

public PrintVisitor()

Creates a visitor to create and print string representations of an expression tree.

Method Detail

init

public void init(Jep jep)

Description copied from interface: JepComponent

Initialize the component. This methods is called whenever a component is added to Jep. Hence it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

jep - the current Jep instance

print

public void print(Node node,
                  java.io.PrintStream out)

Prints the tree descending from node with lots of brackets or specified stream.

See Also:

Jep.println(Node, PrintStream)

printWrap

public void printWrap(java.lang.StringBuffer sb,
                      java.io.PrintStream out)

Utility method to print a wrapped version of the output. Each line will be a maximum of maxLen characters wide with lines broken on

Parameters:

sb - the StringBuffer to print

out - the output stream

print

public void print(Node node)

Prints on System.out.

println

public void println(Node node,
                    java.io.PrintStream out)

Prints the tree descending from node with a newline at end.

println

public void println(Node node)

Prints on System.out.

toString

public java.lang.String toString(Node node)

Returns a String representation of the equation.

append

public void append(java.lang.String s)

Add a string to buffer. Classes implementing PrintRulesI should call this method.

Parameters:

s - the string to append

Since:

3.4.0

addSpecialRule

public void addSpecialRule(Operator op,
                           PrintVisitor.PrintRulesI rule)

Adds a special print rule to be added for a given operator.

Parameters:

op - the operator the rule applies to

rule - the print rule to use

addSpecialRule

public void addSpecialRule(java.lang.String funName,
                           PrintVisitor.PrintRulesI rule)

Adds a special print rule to be added for a given function.

Parameters:

funName - name of function

rule - the print rule to use

addSpecialVarName

public java.lang.String addSpecialVarName(java.lang.String oldName,
                                          java.lang.String newName)

Allows a replacement for a specific variable name

Parameters:

oldName - name of variable to replace

newName - string to print as replacement

printNoBrackets

public void printNoBrackets(Node node)
                     throws JepException

Print the node with no brackets.

Throws:

JepException

printBrackets

public void printBrackets(Node node)
                   throws JepException

Print a node surrounded by brackets.

Throws:

JepException

visit

public java.lang.Object visit(ASTFunNode node,
                              java.lang.Object data)
                       throws JepException

Prints a standard function: fun(arg, arg)

Specified by:

visit in interface ParserVisitor

Throws:

JepException

visit

public java.lang.Object visit(ASTOpNode node,
                              java.lang.Object data)
                       throws JepException

Specified by:

visit in interface ParserVisitor

Throws:

JepException

visit

public java.lang.Object visit(ASTVarNode node,
                              java.lang.Object data)
                       throws JepException

Specified by:

visit in interface ParserVisitor

Throws:

JepException

visit

public java.lang.Object visit(ASTConstant node,
                              java.lang.Object data)
                       throws JepException

Specified by:

visit in interface ParserVisitor

Throws:

JepException

formatValue

public void formatValue(java.lang.Object val,
                        java.lang.StringBuffer sb1)

Appends a formatted versions of val to the string buffer.

Parameters:

val - The value to format

sb1 - The StringBuffer to append to

formatValue

public java.lang.String formatValue(java.lang.Object val)

Returns a formatted version of the value.

getMode

public int getMode()

Return the current print mode. Note that the mode is a bit field.

getMode

public boolean getMode(int testmode)

Returns true if the specified testmode is active.

Parameters:

testmode - The mode to check.

Returns:

True if the specified mode is active.

setMode

public void setMode(int mode,
                    boolean flag)

Set printing mode. In full bracket mode the brackets each element in the tree will be surrounded by brackets to indicate the tree structure. In the default mode, (full bracket off) the number of brackets is minimized so (x+y)+z will be printed as x+y+z.

Parameters:

mode - which flags to change, typically FULL_BRACKET

flag - whether to switch this mode on or off

setNumberFormat

public void setNumberFormat(java.text.NumberFormat format)

setMaxLen

public void setMaxLen(int i)

Sets the maximum length printed per line. If the value is not -1 then the string will be broken into chunks each of which is less than the max length.

Parameters:

i - the maximum length

getMaxLen

public int getMaxLen()

Returns:

the maximum length printed per line

getLightWeightInstance

public JepComponent getLightWeightInstance()

Description copied from interface: JepComponent

Gets a light-weight instance suitable for using in multiple threads.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

either an new instance, or 'this'.

getLBracket

public java.lang.String getLBracket()

Get the string for left brackets.

setLBracket

public void setLBracket(java.lang.String bracket)

Set the string for left brackets.

getRBracket

public java.lang.String getRBracket()

Get the string for right brackets.

setRBracket

public void setRBracket(java.lang.String bracket)

Set the string for right brackets.

getFunLBracket

public java.lang.String getFunLBracket()

Get the string for left bracket around function arguments.

setFunLBracket

public void setFunLBracket(java.lang.String funLBracket)

Set the string for left bracket around function arguments.

getFunRBracket

public java.lang.String getFunRBracket()

Get the string for right bracket around function arguments.

setFunRBracket

public void setFunRBracket(java.lang.String funRBracket)

Set the string for right bracket around function arguments.

getFunArgSep

public java.lang.String getFunArgSep()

Get the string separating function arguments.

setFunArgSep

public void setFunArgSep(java.lang.String functionArgSep)

Set the string separating function arguments.