Package org.apache.commons.jxpath.ri.compiler

Class CoreOperation

java.lang.Object

org.apache.commons.jxpath.ri.compiler.Expression

org.apache.commons.jxpath.ri.compiler.Operation

org.apache.commons.jxpath.ri.compiler.CoreOperation

Direct Known Subclasses:

CoreOperationAdd, CoreOperationAnd, CoreOperationCompare, CoreOperationDivide, CoreOperationMod, CoreOperationMultiply, CoreOperationNegate, CoreOperationOr, CoreOperationRelationalExpression, CoreOperationSubtract, CoreOperationUnion

public abstract class CoreOperation
extends Operation

The common subclass for tree elements representing core operations like "+", "- ", "*" etc.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.jxpath.ri.compiler.Expression

Expression.PointerIterator, Expression.ValueIterator

Field Summary

Fields

Modifier and Type	Field	Description
protected static final int	ADD_PRECEDENCE	Add/subtract precedence
protected static final int	AND_PRECEDENCE	And precedence
protected static final int	COMPARE_PRECEDENCE	Compare precedence
protected static final int	MULTIPLY_PRECEDENCE	Multiply/divide/mod precedence
protected static final int	NEGATE_PRECEDENCE	Negate precedence
protected static final int	OR_PRECEDENCE	Or precedence
protected static final int	RELATIONAL_EXPR_PRECEDENCE	Relational expression precedence
protected static final int	UNION_PRECEDENCE	Union precedence

Fields inherited from class org.apache.commons.jxpath.ri.compiler.Operation

args

Fields inherited from class org.apache.commons.jxpath.ri.compiler.Expression

NOT_A_NUMBER, ONE, ZERO

Constructor Summary

Constructors

Constructor	Description
CoreOperation(Expression[] args)	Constructs a new CoreOperation.

Method Summary

Modifier and Type	Method	Description
Object	compute(EvalContext context)	Evaluates the expression.
abstract Object	computeValue(EvalContext context)	Evaluates the expression.
protected abstract int	getPrecedence()	Computes the precedence of the operation.
abstract String	getSymbol()	Returns the XPath symbol for this operation, e.g. "+", "div", etc.
protected abstract boolean	isSymmetric()	Returns true if the operation is not sensitive to the order of arguments, e.g. "=", "and" etc, and false if it is, e.g
String	toString()

Methods inherited from class org.apache.commons.jxpath.ri.compiler.Operation

computeContextDependent, getArguments

Methods inherited from class org.apache.commons.jxpath.ri.compiler.Expression

isContextDependent, iterate, iteratePointers

Methods inherited from class java.lang.Object

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

Field Details

OR_PRECEDENCE

protected static final int OR_PRECEDENCE

Or precedence

See Also:

• Constant Field Values

AND_PRECEDENCE

protected static final int AND_PRECEDENCE

And precedence

See Also:

• Constant Field Values

COMPARE_PRECEDENCE

protected static final int COMPARE_PRECEDENCE

Compare precedence

See Also:

• Constant Field Values

RELATIONAL_EXPR_PRECEDENCE

protected static final int RELATIONAL_EXPR_PRECEDENCE

Relational expression precedence

See Also:

• Constant Field Values

ADD_PRECEDENCE

protected static final int ADD_PRECEDENCE

Add/subtract precedence

See Also:

• Constant Field Values

MULTIPLY_PRECEDENCE

protected static final int MULTIPLY_PRECEDENCE

Multiply/divide/mod precedence

See Also:

• Constant Field Values

NEGATE_PRECEDENCE

protected static final int NEGATE_PRECEDENCE

Negate precedence

See Also:

• Constant Field Values

UNION_PRECEDENCE

protected static final int UNION_PRECEDENCE

Union precedence

See Also:

• Constant Field Values

Constructor Details

CoreOperation

public CoreOperation(Expression[] args)

Constructs a new CoreOperation.

Parameters:

args - Expression[]

Method Details

compute

public Object compute(EvalContext context)

Description copied from class: Expression

Evaluates the expression. If the result is a node set, returns the first element of the node set.

Specified by:

compute in class Expression

Parameters:

context - evaluation context

Returns:

Object

computeValue

public abstract Object computeValue(EvalContext context)

Description copied from class: Expression

Evaluates the expression. If the result is a node set, returns the first element of the node set.

Specified by:

computeValue in class Expression

Parameters:

context - evaluation context

Returns:

Object

getPrecedence

protected abstract int getPrecedence()

Computes the precedence of the operation.

Returns:

int precedence

getSymbol

public abstract String getSymbol()

Returns the XPath symbol for this operation, e.g. "+", "div", etc.

Returns:

String symbol

isSymmetric

protected abstract boolean isSymmetric()

Returns true if the operation is not sensitive to the order of arguments, e.g. "=", "and" etc, and false if it is, e.g. "<=", "div".

Returns:

boolean

toString

public String toString()

Overrides:

toString in class Object