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

All Implemented Interfaces:

JepComponent, ParserVisitor, java.io.Serializable

Direct Known Subclasses:

DPrintVisitor, PrintVisitor.NullPrintVisitor
```
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, 4.0 Operators can implement PrintRulesI

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

Nested Classes
Modifier and Type	Class	Description
`static class`	`PrintVisitor.NullPrintVisitor`	A do-nothing version of a PrintVisitor for reducing memory usage.
`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

Fields
Modifier and Type	Field	Description
`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.
`protected java.text.FieldPosition`	`fp`
`static int`	`FULL_BRACKET`	Enable this mode to print all brackets.
`protected java.lang.String`	`FunctionArgSep`
`protected java.lang.String`	`FunLBracket`
`protected java.lang.String`	`FunRBracket`
`protected java.lang.String`	`LBracket`
`protected int`	`mode`	The current mode for printing.
`static PrintVisitor.NullPrintVisitor`	`NULL_PRINT_VISITOR`	A do-nothing PrintVisitor, useful for reducing memory usage when printing not required.
`protected OperatorTableI`	`ot`
`protected java.lang.String`	`RBracket`
`protected java.lang.StringBuffer`	`sb`
`protected java.util.HashMap<java.lang.String,PrintVisitor.PrintRulesI>`	`specialFunRules`
`protected java.util.HashMap<Operator,PrintVisitor.PrintRulesI>`	`specialRules`
`protected java.util.HashMap<java.lang.String,java.lang.String>`	`specialVarName`

Constructor Summary

Constructors
Constructor Description

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

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`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 sb1, 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)`	Sets the number format to use.
`void`	`setRBracket(java.lang.String bracket)`	Set the string for right brackets.
`boolean`	`testLeft(Operator top, Node lhs)`	Test if brackets are necessary around left hand side.
`boolean`	`testMid(Operator top, Node mid)`	Test if brackets are needed around a middle argument `x + (y) + z`
`boolean`	`testRight(Operator top, Node rhs)`	Tests if brackets are necessary around the RHS child of a operator.
`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)`
`protected void`	`visitBinary(ASTOpNode node)`
`protected void`	`visitUnary(ASTOpNode node)`	Print a unary operator.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LBracket
```
protected java.lang.String LBracket
```
  - RBracket
```
protected java.lang.String RBracket
```
  - FunLBracket
```
protected java.lang.String FunLBracket
```
  - FunRBracket
```
protected java.lang.String FunRBracket
```
  - FunctionArgSep
```
protected java.lang.String FunctionArgSep
```
  - 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.
  - specialRules
```
protected java.util.HashMap<Operator,PrintVisitor.PrintRulesI> specialRules
```
  - specialFunRules
```
protected java.util.HashMap<java.lang.String,PrintVisitor.PrintRulesI> specialFunRules
```
  - specialVarName
```
protected java.util.HashMap<java.lang.String,java.lang.String> specialVarName
```
  - format
```
protected java.text.NumberFormat format
```
    The NumberFormat object used to print numbers.
  - fp
```
protected transient java.text.FieldPosition fp
```
  - ot
```
protected OperatorTableI ot
```
  - NULL_PRINT_VISITOR
```
public static final PrintVisitor.NullPrintVisitor NULL_PRINT_VISITOR
```
    A do-nothing PrintVisitor, useful for reducing memory usage when printing not required. This is static Singleton instance which can be safely be reused.
    
    Since:
    
    3.5
- 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 sb1,
                      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:
    
    sb1 - 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 PrintVisitor.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
  - visitUnary
```
protected void visitUnary(ASTOpNode node)
                   throws JepException
```
    Print a unary operator.
    
    Throws:
    
    JepException
  - visitBinary
```
protected void visitBinary(ASTOpNode node)
                    throws JepException
```
    Throws:
    
    JepException
  - testLeft
```
public boolean testLeft(Operator top,
                        Node lhs)
```
    Test if brackets are necessary around left hand side.
    
    Parameters:
    
    top - The current operator being printed.
    
    lhs - The node on the left hand side.
    
    Returns:
    
    True if a bracket is necessary, false otherwise.
  - testMid
```
public boolean testMid(Operator top,
                       Node mid)
```
    Test if brackets are needed around a middle argument x + (y) + z
    
    Parameters:
    
    top - The current operator being printed.
    
    mid - The node on the middle of a chain.
    
    Returns:
    
    True if a bracket is necessary, false otherwise.
  - testRight
```
public boolean testRight(Operator top,
                         Node rhs)
```
    Tests if brackets are necessary around the RHS child of a operator.
    
    Parameters:
    
    top - The operator.
    
    rhs - The right hand side node.
    
    Returns:
    
    True if brackets are necessary, false otherwise.
  - 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)
```
    Sets the number format to use. A useful format is a DecimalFormat with minimum fraction digits set to zero. This makes simple powers, like x^2, print nicely.
    DecimalFormat fmt = new DecimalFormat(); fmt.setMinimumFractionDigits(0); fmt.setMaximumFractionDigits(15); jep.getPrintVisitor().setNumberFormat(fmt);
    Parameters:
    
    format - format to use, if null just uses toString
  - 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, null 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.

Class PrintVisitor

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LBracket

RBracket

FunLBracket

FunRBracket

FunctionArgSep

FULL_BRACKET

COMPLEX_I

sb

mode

specialRules

specialFunRules

specialVarName

format

fp

ot

NULL_PRINT_VISITOR

Constructor Detail

PrintVisitor

Method Detail

init

print

printWrap

print

println

println

toString

append

addSpecialRule

addSpecialRule

addSpecialVarName

printNoBrackets

printBrackets

visitUnary

visitBinary

testLeft

testMid

testRight

visit

visit

visit

visit

formatValue

formatValue

getMode

getMode

setMode

setNumberFormat

setMaxLen

getMaxLen

getLightWeightInstance

getLBracket

setLBracket

getRBracket

setRBracket

getFunLBracket

setFunLBracket

getFunRBracket

setFunRBracket

getFunArgSep

setFunArgSep