org.treetank.service.xml.xpath.comparators

Class AbsComparator

java.lang.Object

org.treetank.axis.AbsAxis

org.treetank.service.xml.xpath.comparators.AbsComparator

All Implemented Interfaces:

Iterable<Long>, Iterator<Long>

Direct Known Subclasses:

GeneralComp, NodeComp, ValueComp

public abstract class AbsComparator
extends AbsAxis

AbstractComparator

Abstract axis that evaluates a comparison.

Constructor Summary

Constructors

Constructor and Description
AbsComparator(INodeReadTrx mRtx, AbsAxis mOperand1, AbsAxis mOperand2, CompKind mComp) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract AtomicValue[]	atomize(AbsAxis paramOperand) Atomizes an operand according to the rules specified in the XPath specification.
protected abstract boolean	compare(AtomicValue[] paramOperandOne, AtomicValue[] paramOperandTwo) Performs the comparison of two atomic values.
static AbsComparator	getComparator(INodeReadTrx paramRtx, AbsAxis paramOperandOne, AbsAxis paramOperandTwo, CompKind paramKind, String paramVal) Factory method to implement the comparator.
CompKind	getCompKind() Getting CompKind for this Comparator.
protected abstract Type	getType(int mKey1, int mKey2) Returns the common comparable type of the two operands, or an error, if the two operands don't have a common type on which a comparison is allowed according to the XPath 2.0 specification.
boolean	hasNext()
protected void	hook(AtomicValue[] paramOperandOne, AtomicValue[] paramOperandTwo) Allowes the general comparisons to do some extra functionality.
void	reset(long mNodeKey) Resetting the nodekey of this axis to a given nodekey.

Methods inherited from class org.treetank.axis.AbsAxis

addAtomicToItemList, close, getItemList, getNode, getStartKey, isSelfIncluded, iterator, moveTo, next, remove, resetToLastKey, resetToStartKey

Methods inherited from class java.lang.Object

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

Constructor Detail

AbsComparator

public AbsComparator(INodeReadTrx mRtx,
             AbsAxis mOperand1,
             AbsAxis mOperand2,
             CompKind mComp)

Constructor. Initializes the internal state.

Parameters:

mRtx - Exclusive (immutable) trx to iterate with.

mOperand1 - First value of the comparison

mOperand2 - Second value of the comparison

mComp - comparison kind

Method Detail

reset

public final void reset(long mNodeKey)

Resetting the nodekey of this axis to a given nodekey.

Overrides:

reset in class AbsAxis

Parameters:

mNodeKey - the nodekey where the reset should occur to.

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface Iterator<Long>

Specified by:

hasNext in class AbsAxis

hook

protected void hook(AtomicValue[] paramOperandOne,
        AtomicValue[] paramOperandTwo)

Allowes the general comparisons to do some extra functionality.

Parameters:

paramOperandOne - first operand

paramOperandTwo - second operand

compare

protected abstract boolean compare(AtomicValue[] paramOperandOne,
              AtomicValue[] paramOperandTwo)
                            throws TTXPathException

Performs the comparison of two atomic values.

Parameters:

paramOperandOne - first comparison operand.

paramOperandTwo - second comparison operand.

Returns:

the result of the comparison

Throws:

TTXPathException

atomize

protected abstract AtomicValue[] atomize(AbsAxis paramOperand)
                                  throws TTXPathException

Atomizes an operand according to the rules specified in the XPath specification.

Parameters:

paramOperand - the operand that will be atomized.

Returns:

the atomized operand. (always an atomic value)

Throws:

TTXPathException - if any goes wrong.

getType

protected abstract Type getType(int mKey1,
           int mKey2)
                         throws TTXPathException

Returns the common comparable type of the two operands, or an error, if the two operands don't have a common type on which a comparison is allowed according to the XPath 2.0 specification.

Parameters:

mKey1 - first comparison operand's type key

mKey2 - second comparison operand's type key

Returns:

the type the comparison can be evaluated on

Throws:

TTXPathException

getCompKind

public final CompKind getCompKind()

Getting CompKind for this Comparator.

Returns:

comparison kind

getComparator

public static final AbsComparator getComparator(INodeReadTrx paramRtx,
                          AbsAxis paramOperandOne,
                          AbsAxis paramOperandTwo,
                          CompKind paramKind,
                          String paramVal)

Factory method to implement the comparator.

Parameters:

paramRtx - rtx for accessing data

paramOperandOne - operand one to be compared

paramOperandTwo - operand two to be compared

paramKind - kind of comparison

paramVal - string value to estimate

Returns:

AbsComparator the comparator of two axis