JEP (onecode-common-client 1.1.1 API)

java.lang.Object
- com.ds.common.expression.JEP

所有已实现的接口:

ExpressionParser
```
public class JEP
extends Object
implements ExpressionParser
```
Title: 常用代码打包

Description: 表达式解析器

The JEP class is the main interface with which the user should interact. It contains all necessary methods to parse and evaluate expressions.

The most important methods are parseExpression(String), for parsing the mathematical or other expression, and getValue() or getValueAsObject for obtaining the value of the expression.

Copyright: Copyright spk (c) 2003

Company: spk

版本:

1.0

作者:

chenjie

字段概要

字段
限定符和类型	字段和说明
`protected boolean`	`allowUndeclared` Allow undeclared variables option
`protected Vector`	`errorList` Error List
`protected FunctionTable`	`funTab` Function Table
`protected boolean`	`implicitMul` Implicit multiplication option
`protected static Log`	`log`
`protected SymbolTable`	`symTab` Symbol Table

构造器概要

构造器
构造器和说明
`JEP()` Creates a new JEP instance with the default settings.
`JEP(boolean traverse_in, boolean allowUndeclared_in, boolean implicitMul_in, NumberFactory numberFactory_in)` Creates a new JEP instance with custom settings.

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`void`	`addFunction(String functionName, Function function)` 加入函数
`void`	`addFunction(String functionName, FunctionI function)` Adds a new function to the parser.
`void`	`addFuntionTable(FunctionTable functionTable)` 加入函数表
`void`	`addStandardConstants()` Adds the constants pi and e to the parser.
`void`	`addStandardFunctions()` Adds the standard functions to the parser.
`Double`	`addVariable(String name, double value)` Adds a new variable to the parser, or updates the value of an existing variable.
`void`	`addVariableAsObject(String name, Object object)` Adds a new variable to the parser as an object, or updates the value of an existing variable.
`void`	`addVariableNames(String[] names)` 加入变量名，用于解析表达式用。
`String`	`getErrorInfo()` Reports information on the errors that occured during the most recent action.
`String`	`getExpression()` 取得Parser中当前的表达式
`Hashtable`	`getFunctionTable()` Returns the function table (the list of all functions that the parser recognizes).
`NumberFactory`	`getNumberFactory()` Returns the number factory.
`HashMap`	`getSymbolTable()` Returns the symbol table (the list of all variables that the parser recognises).
`Node`	`getTopNode()` Returns the top node of the expression tree.
`double`	`getValue()` Evaluates and returns the value of the expression.
`Object`	`getValueAsObject()` Evaluates and returns the value of the expression as an object.
`boolean`	`hasError()` Returns true if an error occured during the most recent action (parsing or evaluation).
`void`	`initFunTab()` Creates a new FunctionTable object as funTab.
`void`	`initSymTab()` Creates a new SymbolTable object as symTab.
`boolean`	`parseExpression(String expression_in)` Parses the expression.
`Object`	`removeFunction(String name)` Removes a function from the parser.
`Object`	`removeVariable(String name)` Removes a variable from the parser.
`void`	`setAllowUndeclared(boolean value)` Sets the value for the undeclared variables option.
`void`	`setImplicitMul(boolean value)` Sets the value of the implicit multiplication option.
`void`	`setTraverse(boolean value)` Sets the value of the traverse option. setTraverse is useful for debugging purposes.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - log
```
protected static Log log
```
  - allowUndeclared
```
protected boolean allowUndeclared
```
    Allow undeclared variables option
  - implicitMul
```
protected boolean implicitMul
```
    Implicit multiplication option
  - symTab
```
protected SymbolTable symTab
```
    Symbol Table
  - funTab
```
protected FunctionTable funTab
```
    Function Table
  - errorList
```
protected Vector errorList
```
    Error List
- 构造器详细资料
  - JEP
```
public JEP()
```
    Creates a new JEP instance with the default settings.
    Traverse = false
    Allow undeclared variables = false
    Implicit multiplication = false
    Number Factory = DoubleNumberFactory
  - JEP
```
public JEP(boolean traverse_in,
           boolean allowUndeclared_in,
           boolean implicitMul_in,
           NumberFactory numberFactory_in)
```
    Creates a new JEP instance with custom settings. If the numberFactory_in is null, the default number factory is used.
    
    参数:
    
    traverse_in - The traverse option.
    
    allowUndeclared_in - The "allow undeclared variables" option.
    
    implicitMul_in - The implicit multiplication option.
    
    numberFactory_in - The number factory to be used.
- 方法详细资料
  - getExpression
```
public String getExpression()
```
    从接口复制的说明: ExpressionParser
    
    取得Parser中当前的表达式
    
    指定者:
    
    getExpression 在接口中 ExpressionParser
    
    返回:
    
    Parser中当前的表达式
  - initSymTab
```
public void initSymTab()
```
    Creates a new SymbolTable object as symTab.
  - initFunTab
```
public void initFunTab()
```
    Creates a new FunctionTable object as funTab.
  - addStandardFunctions
```
public void addStandardFunctions()
```
    Adds the standard functions to the parser. If this function is not called before parsing an expression, functions such as sin() or cos() would produce an "Unrecognized function..." error. In most cases, this method should be called immediately after the JEP object is created.
    
    指定者:
    
    addStandardFunctions 在接口中 ExpressionParser
  - addStandardConstants
```
public void addStandardConstants()
```
    Adds the constants pi and e to the parser. As addStandardFunctions(), this method should be called immediatly after the JEP object is created.
    
    指定者:
    
    addStandardConstants 在接口中 ExpressionParser
  - addFunction
```
public void addFunction(String functionName,
                        FunctionI function)
```
    Adds a new function to the parser. This must be done before parsing an expression so the parser is aware that the new function may be contained in the expression.
    
    参数:
    
    functionName - The name of the function
    
    function - The function object that is used for evaluating the function
  - addFunction
```
public void addFunction(String functionName,
                        Function function)
```
    从接口复制的说明: ExpressionParser
    
    加入函数
    
    指定者:
    
    addFunction 在接口中 ExpressionParser
    
    参数:
    
    functionName - 函数的名称
    
    function - 要加入的函数
  - addFuntionTable
```
public void addFuntionTable(FunctionTable functionTable)
```
    加入函数表
    
    指定者:
    
    addFuntionTable 在接口中 ExpressionParser
  - addVariable
```
public Double addVariable(String name,
                          double value)
```
    Adds a new variable to the parser, or updates the value of an existing variable. This must be done before parsing an expression so the parser is aware that the new variable may be contained in the expression.
    
    参数:
    
    name - Name of the variable to be added
    
    value - Initial value or new value for the variable
    
    返回:
    
    Double object of the variable
  - addVariableAsObject
```
public void addVariableAsObject(String name,
                                Object object)
```
    Adds a new variable to the parser as an object, or updates the value of an existing variable. This must be done before parsing an expression so the parser is aware that the new variable may be contained in the expression.
    
    指定者:
    
    addVariableAsObject 在接口中 ExpressionParser
    
    参数:
    
    name - Name of the variable to be added
    
    object - Initial value or new value for the variable
  - removeVariable
```
public Object removeVariable(String name)
```
    Removes a variable from the parser. For example after calling addStandardConstants(), removeVariable("e") might be called to remove the euler constant from the set of variables.
    
    指定者:
    
    removeVariable 在接口中 ExpressionParser
    
    参数:
    
    name - 变量的名称
    
    返回:
    
    The value of the variable if it was added earlier. If the variable is not in the table of variables, null is returned.
  - removeFunction
```
public Object removeFunction(String name)
```
    Removes a function from the parser.
    
    指定者:
    
    removeFunction 在接口中 ExpressionParser
    
    参数:
    
    name - 函数的名称
    
    返回:
    
    If the function was added earlier, the function class instance is returned. If the function was not present, null is returned.
  - setTraverse
```
public void setTraverse(boolean value)
```
    Sets the value of the traverse option. setTraverse is useful for debugging purposes. When traverse is set to true, the parse-tree will be dumped to the standard ouput device.
    The default value is false.
    
    参数:
    
    value - The boolean traversal option.
  - setImplicitMul
```
public void setImplicitMul(boolean value)
```
    Sets the value of the implicit multiplication option. If this option is set to true before parsing, implicit multiplication will be allowed. That means that an expression such as
```
 "1 2"
 
```
    is valid and is interpreted as
```
 "1*2"
 
```
    .
    The default value is false.
    参数:
    
    value - The boolean implicit multiplication option.
  - setAllowUndeclared
```
public void setAllowUndeclared(boolean value)
```
    Sets the value for the undeclared variables option. If this option is set to true, expressions containing variables that were not previously added to JEP will not produce an "Unrecognized Symbol" error. The new variables will automatically be added while parsing, and initialized to 0.
    If this option is set to false, variables that were not previously added to JEP will produce an error while parsing.
    The default value is false.
    
    指定者:
    
    setAllowUndeclared 在接口中 ExpressionParser
    
    参数:
    
    value - The boolean option for allowing undeclared variables.
  - parseExpression
```
public boolean parseExpression(String expression_in)
```
    Parses the expression. If there are errors in the expression, they are added to the errorList member.
    
    指定者:
    
    parseExpression 在接口中 ExpressionParser
    
    参数:
    
    expression_in - The input expression string
    
    返回:
    
    true-解析成功, false-解析失败
  - getValue
```
public double getValue()
                throws Exception
```
    Evaluates and returns the value of the expression. If the value is complex, the real component of the complex number is returned. To get the complex value, use getComplexValue().
    
    返回:
    
    The calculated value of the expression. If the value is complex, the real component is returned. If an error occurs during evaluation, 0 is returned.
    
    抛出:
    
    Exception
  - getValueAsObject
```
public Object getValueAsObject()
```
    Evaluates and returns the value of the expression as an object. The EvaluatorVisitor member ev is used to do the evaluation procedure. This method is useful when the type of the value is unknown, or not important.
    
    指定者:
    
    getValueAsObject 在接口中 ExpressionParser
    
    返回:
    
    The calculated value of the expression if no errors occur. Returns null otherwise.
  - hasError
```
public boolean hasError()
```
    Returns true if an error occured during the most recent action (parsing or evaluation).
    
    指定者:
    
    hasError 在接口中 ExpressionParser
    
    返回:
    
    Returns true if an error occured during the most recent action (parsing or evaluation).
  - getErrorInfo
```
public String getErrorInfo()
```
    Reports information on the errors that occured during the most recent action.
    
    指定者:
    
    getErrorInfo 在接口中 ExpressionParser
    
    返回:
    
    A string containing information on the errors, each separated by a newline character; null if no error has occured
  - getTopNode
```
public Node getTopNode()
```
    Returns the top node of the expression tree. Because all nodes are pointed to either directly or indirectly, the entire expression tree can be accessed through this node. It may be used to manipulate the expression, and subsequently evaluate it manually.
    
    返回:
    
    The top node of the expression tree
  - getSymbolTable
```
public HashMap getSymbolTable()
```
    Returns the symbol table (the list of all variables that the parser recognises).
    
    指定者:
    
    getSymbolTable 在接口中 ExpressionParser
    
    返回:
    
    The symbol table
  - getFunctionTable
```
public Hashtable getFunctionTable()
```
    Returns the function table (the list of all functions that the parser recognizes).
    
    指定者:
    
    getFunctionTable 在接口中 ExpressionParser
    
    返回:
    
    The function table
  - getNumberFactory
```
public NumberFactory getNumberFactory()
```
    Returns the number factory.
  - addVariableNames
```
public void addVariableNames(String[] names)
```
    从接口复制的说明: ExpressionParser
    
    加入变量名，用于解析表达式用。
    
    指定者:
    
    addVariableNames 在接口中 ExpressionParser

类 JEP

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

log

allowUndeclared

implicitMul

symTab

funTab

errorList

构造器详细资料

JEP

JEP

方法详细资料

getExpression

initSymTab

initFunTab

addStandardFunctions

addStandardConstants

addFunction

addFunction

addFuntionTable

addVariable

addVariableAsObject

removeVariable

removeFunction

setTraverse

setImplicitMul

setAllowUndeclared

parseExpression

getValue

getValueAsObject

hasError

getErrorInfo

getTopNode

getSymbolTable

getFunctionTable

getNumberFactory

addVariableNames