net.sf.saxon.expr
public abstract class BinaryExpression extends ComputedExpression
Field Summary | |
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protected Expression | operand0 |
protected Expression | operand1 |
protected int | operator |
Constructor Summary | |
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BinaryExpression(Expression p0, int op, Expression p1)
Create a binary expression identifying the two operands and the operator |
Method Summary | |
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int | computeCardinality()
Determine the static cardinality. |
int | computeSpecialProperties()
Determine the special properties of this expression |
void | display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure |
protected String | displayOperator() |
boolean | equals(Object other)
Is this expression the same as another expression? |
Expression[] | getOperands()
Get the operands |
int | getOperator()
Get the operator |
int | hashCode()
Get a hashCode for comparing two expressions. |
protected static boolean | isAssociative(int operator)
Determine whether an operator is associative, that is, ((a^b)^c) = (a^(b^c)) |
protected static boolean | isCommutative(int operator)
Determine whether a binary operator is commutative, that is, A op B = B op A. |
protected static boolean | isInverse(int op1, int op2)
Test if one operator is the inverse of another, so that (A op1 B) is
equivalent to (B op2 A). |
Iterator | iterateSubExpressions()
Get the immediate subexpressions of this expression |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | promote(PromotionOffer offer)
Promote this expression if possible |
Expression | simplify(StaticContext env)
Simplify an expression |
Expression | typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression. |
Parameters: p0 the left-hand operand op the operator, as a token returned by the Tokenizer (e.g. Token.AND) p1 the right-hand operand
Returns: NON_CREATIVE. This is overridden for some subclasses.
Parameters: operator
Returns: true if the operator is commutative
Parameters: op1 the first operator op2 the second operator
Returns: true if the operators are the inverse of each other
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
Parameters: opt the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances. env the static context of the expression contextItemType the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to ITEM_TYPE
Returns: the original expression, rewritten if appropriate to optimize execution
Throws: net.sf.saxon.trans.StaticError if an error is discovered during this phase (typically a type error)
Returns: the simplified expression