Class CoreOperationRelationalExpression
- java.lang.Object
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- org.apache.commons.jxpath.ri.compiler.Expression
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- org.apache.commons.jxpath.ri.compiler.Operation
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- org.apache.commons.jxpath.ri.compiler.CoreOperation
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- org.apache.commons.jxpath.ri.compiler.CoreOperationRelationalExpression
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- Direct Known Subclasses:
CoreOperationGreaterThan
,CoreOperationGreaterThanOrEqual
,CoreOperationLessThan
,CoreOperationLessThanOrEqual
public abstract class CoreOperationRelationalExpression extends CoreOperation
Base implementation of Expression for the operations ">", ">=", "<", "<=".- Since:
- JXPath 1.3
- Version:
- $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.commons.jxpath.ri.compiler.Expression
Expression.PointerIterator, Expression.ValueIterator
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Field Summary
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Fields inherited from class org.apache.commons.jxpath.ri.compiler.CoreOperation
ADD_PRECEDENCE, AND_PRECEDENCE, COMPARE_PRECEDENCE, MULTIPLY_PRECEDENCE, NEGATE_PRECEDENCE, OR_PRECEDENCE, RELATIONAL_EXPR_PRECEDENCE, UNION_PRECEDENCE
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Fields inherited from class org.apache.commons.jxpath.ri.compiler.Expression
NOT_A_NUMBER, ONE, ZERO
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Constructor Summary
Constructors Modifier Constructor Description protected
CoreOperationRelationalExpression(Expression[] args)
Create a new CoreOperationRelationalExpression.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description private boolean
compute(java.lang.Object left, java.lang.Object right)
Compare left to right.java.lang.Object
computeValue(EvalContext context)
Evaluates the expression.private boolean
containsMatch(java.util.Iterator it, java.lang.Object value)
Learn whether any element returned from an Iterator matches a given value.protected abstract boolean
evaluateCompare(int compare)
Template method for subclasses to evaluate the result of a comparison.private boolean
findMatch(java.util.Iterator lit, java.util.Iterator rit)
Learn whether there is an intersection between two Iterators.protected int
getPrecedence()
Computes the precedence of the operation.protected boolean
isSymmetric()
Returns true if the operation is not sensitive to the order of arguments, e.g.private java.lang.Object
reduce(java.lang.Object o)
Reduce an operand for comparison.-
Methods inherited from class org.apache.commons.jxpath.ri.compiler.CoreOperation
compute, getSymbol, toString
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Methods inherited from class org.apache.commons.jxpath.ri.compiler.Operation
computeContextDependent, getArguments
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Methods inherited from class org.apache.commons.jxpath.ri.compiler.Expression
isContextDependent, iterate, iteratePointers
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Constructor Detail
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CoreOperationRelationalExpression
protected CoreOperationRelationalExpression(Expression[] args)
Create a new CoreOperationRelationalExpression.- Parameters:
args
- arguments
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Method Detail
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computeValue
public final java.lang.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 classCoreOperation
- Parameters:
context
- evaluation context- Returns:
- Object
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getPrecedence
protected final int getPrecedence()
Description copied from class:CoreOperation
Computes the precedence of the operation.- Specified by:
getPrecedence
in classCoreOperation
- Returns:
- int precedence
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isSymmetric
protected final boolean isSymmetric()
Description copied from class:CoreOperation
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".- Specified by:
isSymmetric
in classCoreOperation
- Returns:
- boolean
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evaluateCompare
protected abstract boolean evaluateCompare(int compare)
Template method for subclasses to evaluate the result of a comparison.- Parameters:
compare
- result of comparison to evaluate- Returns:
- ultimate operation success/failure
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compute
private boolean compute(java.lang.Object left, java.lang.Object right)
Compare left to right.- Parameters:
left
- left operandright
- right operand- Returns:
- operation success/failure
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reduce
private java.lang.Object reduce(java.lang.Object o)
Reduce an operand for comparison.- Parameters:
o
- Object to reduce- Returns:
- reduced operand
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containsMatch
private boolean containsMatch(java.util.Iterator it, java.lang.Object value)
Learn whether any element returned from an Iterator matches a given value.- Parameters:
it
- Iteratorvalue
- to look for- Returns:
- whether a match was found
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findMatch
private boolean findMatch(java.util.Iterator lit, java.util.Iterator rit)
Learn whether there is an intersection between two Iterators.- Parameters:
lit
- left Iteratorrit
- right Iterator- Returns:
- whether a match was found
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