net.sf.saxon.expr
public abstract class BinaryExpression extends Expression
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 |
protected String | displayOperator()
Display the operator used by this binary expression |
boolean | equals(Object other)
Is this expression the same as another expression? |
void | explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
protected void | explainExtraAttributes(ExpressionPresenter out)
Add subclass-specific attributes to the expression tree explanation. |
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<Expression> | iterateSubExpressions()
Get the immediate subexpressions of this expression |
Expression | optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | promote(PromotionOffer offer, Expression parent)
Promote this expression if possible |
boolean | replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression |
void | setFlattened(boolean flattened)
Mark an expression as being "flattened". |
Expression | simplify(ExpressionVisitor visitor)
Simplify an expression |
String | toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.
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Expression | typeCheck(ExpressionVisitor visitor, 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.
Returns: String representation of the operator (for diagnostic display only)
Parameters: out the output destination for the displayed expression tree
Parameters: out the output destination for the displayed expression tree
Returns: the two operands of the binary expression, as an array of length 2
Returns: the operator, for example PLUS
Parameters: operator the operator, for example PLUS
Returns: true if the operator is associative
Parameters: operator the operator, for example PLUS
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: visitor an expression visitor 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: XPathException if an error is discovered during this phase (typically a type error)
Parameters: original the original subexpression replacement the replacement subexpression
Returns: true if the original subexpression is found
Parameters: flattened set to true if the result of the expression is atomized or otherwise turned into an atomic value
Parameters: visitor an expression visitor
Returns: the simplified expression