Term (SNAP Engine API)

java.lang.Object
- org.esa.snap.core.jexp.Term

Direct Known Subclasses:

Term.Call, Term.Const, Term.Op, Term.Ref
```
public abstract class Term
extends Object
```
The abstract Term class is an in-memory representation of an element within an arbitrary expression tree. The class defines a number of concrete Term implementations each representing either an an atomic leave (number constant, symbol reference) or a node (e.g. binary operator, function call) within an expression tree.
Instances of this class are normally created using an expression parser which implements the Parser interface. The ParserImpl class provides a default implementation of such a parser.

Version:

$Revision$ $Date$

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Term.Add` The numerical ADD operation: n-term `+` n-term
`static class`	`Term.AndB` The logical AND operation: b-term `&&` b-term
`static class`	`Term.AndI` The bitwise AND operation: i-term `&` i-term
`static class`	`Term.Assign` The assignment operation variable-ref-term `=` term
`static class`	`Term.Binary`
`static class`	`Term.BinaryB` An abstract binary (= 2 operands) operation.
`static class`	`Term.BinaryI` An abstract binary (= 2 operands) operation with a return type of `int`.
`static class`	`Term.BinaryN` An abstract binary (= 2 operands) operation with a numeric return type.
`static class`	`Term.Call` A call of a (or reference to a) `Function`.
`static class`	`Term.Cond` The conditional operation b-term `?` term `:` term
`static class`	`Term.Const` A boolean constant, e.g.
`static class`	`Term.ConstB` A boolean constant, e.g.
`static class`	`Term.ConstD` A floating point constant, e.g.
`static class`	`Term.ConstI` An integer constant, e.g.
`static class`	`Term.ConstS`
`static class`	`Term.Div` The numerical DIV operation: n-term `/` n-term
`static class`	`Term.EqB` The boolean EQ operation: b-term `==` b-term
`static class`	`Term.EqD` The double EQ operation: d-term `==` d-term
`static class`	`Term.EqI` The integer EQ operation: i-term `==` i-term
`static class`	`Term.GeD` The double GE operation: d-term `>=` d-term
`static class`	`Term.GeI` The integer GE operation: i-term `>=` i-term
`static class`	`Term.GtD` The double GT operation: d-term `>` d-term
`static class`	`Term.GtI` The integer GT operation: i-term `>` i-term
`static class`	`Term.LeD` The double LE operation: d-term `<=` d-term
`static class`	`Term.LeI` The integer LE operation: i-term `<=` i-term
`static class`	`Term.LtD` The double LT operation: d-term `<` d-term
`static class`	`Term.LtI` The integer LT operation: i-term `<` i-term
`static class`	`Term.Mod` The numerical MOD (modulo) operation: n-term `%` n-term
`static class`	`Term.Mul` The numerical MUL operation: n-term `` n-term*
`static class`	`Term.Neg` The numerical NEG operation: `-` d-term
`static class`	`Term.NEqB` The boolean NEQ operation: b-term `!=` b-term
`static class`	`Term.NEqD` The double NEQ operation: d-term `!=` d-term
`static class`	`Term.NEqI` The integer NEQ operation: i-term `!=` i-term
`static class`	`Term.NotB` The logical NOT operation `!` b-term
`static class`	`Term.NotI` The bitwise NOT operation: `~` i-term
`static class`	`Term.Op` An abstract operation.
`static class`	`Term.OrB` The logical OR operation: b-term `\|\|` b-term
`static class`	`Term.OrI` The bitwise OR operation: i-term `¦` i-term
`static class`	`Term.Ref` A reference to a `Symbol`.
`static class`	`Term.Sub` The numerical SUB operation: n-term `-` n-term
`static class`	`Term.Unary` An abstract unary (= 1 operand) operation.
`static class`	`Term.UnaryB` An abstract unary (= 1 operand) operation with return type of `boolean`.
`static class`	`Term.UnaryI` An abstract unary (= 1 operand) operation with return type of `int`.
`static class`	`Term.UnaryN` An abstract unary (= 1 operand) operation with a numeric return type.
`static class`	`Term.XOrI` The bitwise XOR operation: i-term `^` i-term

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`TYPE_B` The ID for the `boolean` type.
`static int`	`TYPE_D` The ID for the `double` type.
`static int`	`TYPE_I` The ID for the `int` type.
`static int`	`TYPE_S` The ID for the `string` type.

Constructor Summary

Constructors
Constructor and Description

Term()

Constructors
Constructor and Description
`Term()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract <T> T`	`accept(TermVisitor<T> visitor)` Visitor support.
`abstract int`	`compare(Term other)`
`abstract boolean`	`evalB(EvalEnv context)` Evaluates this term to a `boolean` value.
`abstract double`	`evalD(EvalEnv env)` Evaluates this term to a `double` value.
`abstract int`	`evalI(EvalEnv env)` Evaluates this term to an `int` value.
`String`	`evalS(EvalEnv env)` Evaluates this term to a `String` value.
`Term[]`	`getChildren()` Returns an array of terms which are children of this term.
`abstract int`	`getRetType()` Gets the term's "natural" return type.
`boolean`	`isB()` Tests whether or not this term "naturally" returns a `boolean`.
`abstract boolean`	`isConst()`
`boolean`	`isD()` Tests whether or not this term "naturally" returns a `double`.
`boolean`	`isI()` Tests whether or not this term "naturally" returns an `int`.
`boolean`	`isN()` Tests whether or not this term "naturally" returns a numeric value.
`boolean`	`isS()` Tests whether or not this term returns a `String`.
`abstract int`	`pre()`
`static boolean`	`toB(double value)` Converts a `double` to a `boolean`.
`static boolean`	`toB(int value)` Converts an `int` to a `boolean`.
`static double`	`toD(boolean value)` Converts a `boolean` to an `double`.
`static int`	`toI(boolean value)` Converts a `boolean` to an `int`.
`static int`	`toI(double value)` Converts a `double` to an `int`.
`static String`	`toS(boolean value)` Converts a `boolean` to a `String`.
`static String`	`toS(double value)` Converts a `double` to a `String`.
`static String`	`toS(int value)` Converts a `integer` to a `String`.
`abstract String`	`toString()` Returns a string representation of this term which can be used for debugging.

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

- Field Detail
  - TYPE_B
```
public static final int TYPE_B
```
    The ID for the boolean type.
    
    See Also:
    
    Constant Field Values
  - TYPE_I
```
public static final int TYPE_I
```
    The ID for the int type.
    
    See Also:
    
    Constant Field Values
  - TYPE_D
```
public static final int TYPE_D
```
    The ID for the double type.
    
    See Also:
    
    Constant Field Values
  - TYPE_S
```
public static final int TYPE_S
```
    The ID for the string type.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Term
```
public Term()
```
- Method Detail
  - getRetType
```
public abstract int getRetType()
```
    Gets the term's "natural" return type.
    
    Returns:
    
    the type, should always be one of the TYPE_X constants defined in this class.
  - evalB
```
public abstract boolean evalB(EvalEnv context)
```
    Evaluates this term to a boolean value.
    
    Parameters:
    
    context - the application dependant environment.
    
    Returns:
    
    a boolean value
    
    Throws:
    
    EvalException - if the evaluation fails
  - evalI
```
public abstract int evalI(EvalEnv env)
```
    Evaluates this term to an int value.
    
    Parameters:
    
    env - the application dependant environment.
    
    Returns:
    
    an int value
    
    Throws:
    
    EvalException - if the evaluation fails
  - evalD
```
public abstract double evalD(EvalEnv env)
```
    Evaluates this term to a double value.
    
    Parameters:
    
    env - the application dependant environment.
    
    Returns:
    
    a double value
    
    Throws:
    
    EvalException - if the evaluation fails
  - accept
```
public abstract <T> T accept(TermVisitor<T> visitor)
```
    Visitor support.
    
    Parameters:
    
    visitor - A visitor.
  - evalS
```
public String evalS(EvalEnv env)
```
    Evaluates this term to a String value. The default implementation simply returns the value of toString().
    
    Parameters:
    
    env - the application dependant environment.
    
    Returns:
    
    a String value
    
    Throws:
    
    EvalException - if the evaluation fails
  - getChildren
```
public Term[] getChildren()
```
    Returns an array of terms which are children of this term.
    
    Returns:
    
    an array of terms, never null but can be empty
  - toString
```
public abstract String toString()
```
    Returns a string representation of this term which can be used for debugging.
    
    Overrides:
    
    toString in class Object
  - isB
```
public final boolean isB()
```
    Tests whether or not this term "naturally" returns a boolean.
    
    Returns:
    
    true if so
  - isI
```
public final boolean isI()
```
    Tests whether or not this term "naturally" returns an int.
    
    Returns:
    
    true if so
  - isD
```
public final boolean isD()
```
    Tests whether or not this term "naturally" returns a double.
    
    Returns:
    
    true if so
  - isN
```
public final boolean isN()
```
    Tests whether or not this term "naturally" returns a numeric value.
    
    Returns:
    
    true if so
  - isS
```
public final boolean isS()
```
    Tests whether or not this term returns a String.
    
    Returns:
    
    true if so
  - toB
```
public static boolean toB(int value)
```
    Converts an int to a boolean.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value != 0.
  - toB
```
public static boolean toB(double value)
```
    Converts a double to a boolean.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value != 0.0.
  - toI
```
public static int toI(boolean value)
```
    Converts a boolean to an int.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value ? 1 : 0.
  - toI
```
public static int toI(double value)
```
    Converts a double to an int.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is (int) value.
  - toD
```
public static double toD(boolean value)
```
    Converts a boolean to an double.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value ? 1.0 : 0.0.
  - toS
```
public static String toS(boolean value)
```
    Converts a boolean to a String.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value ? 1.0 : 0.0.
  - toS
```
public static String toS(int value)
```
    Converts a integer to a String.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value ? 1.0 : 0.0.
  - toS
```
public static String toS(double value)
```
    Converts a double to a String.
    
    Parameters:
    
    value - the value to be converted
    
    Returns:
    
    the conversion result, which is value ? 1.0 : 0.0.
  - isConst
```
public abstract boolean isConst()
```
    Returns:
    
    true, if this term evaluates to the same constant value regardless of any EvalEnv, even null.
  - compare
```
public abstract int compare(Term other)
```
  - pre
```
public abstract int pre()
```

Class Term

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

TYPE_B

TYPE_I

TYPE_D

TYPE_S

Constructor Detail

Term

Method Detail

getRetType

evalB

evalI

evalD

accept

evalS

getChildren

toString

isB

isI

isD

isN

isS

toB

toB

toI

toI

toD

toS

toS

toS

isConst

compare

pre