org.apache.xpath.compiler

Class OpMap

Known Direct Subclasses:
Compiler

public class OpMap
extends java.lang.Object

This class represents the data structure basics of the XPath object.

Field Summary

static int
MAPINDEX_LENGTH
The length is always the opcode position + 1.

Method Summary

void
error(String msg, Object[] args)
Tell the user of an error, and probably throw an exception.
int
getArgLength(int opPos)
Get the length of an operation.
int
getArgLengthOfStep(int opPos)
Given a location step, get the length of that step.
static int
getFirstChildPos(int opPos)
Go to the first child of a given operation.
static int
getFirstChildPosOfStep(int opPos)
Get the first child position of a given location step.
int
getFirstPredicateOpPos(int opPos)
Given an FROM_stepType position, return the position of the first predicate, if there is one, or else this will point to the end of the FROM_stepType.
int
getNextOpPos(int opPos)
Given an operation position, return the end position, i.e. the beginning of the next operation.
static int
getNextOpPos(int[] opMap, int opPos)
Given an operation position, return the end position, i.e. the beginning of the next operation.
int
getNextStepPos(int opPos)
Given a location step position, return the end position, i.e. the beginning of the next step.
int
getOp(int opPos)
Given an operation position, return the current op.
OpMapVector
getOpMap()
Get the opcode list that describes the XPath operations.
String
getPatternString()
Return the expression as a string for diagnostics.
String
getStepLocalName(int opPosOfStep)
Get the local name of the step.
String
getStepNS(int opPosOfStep)
Get the namespace of the step.
int
getStepTestType(int opPosOfStep)
Get the test type of the step, i.e.
Object
getToken(int pos)
Get the XPath as a list of tokens.
ObjectVector
getTokenQueue()
Get the XPath as a list of tokens.
int
getTokenQueueSize()
Get size of the token queue.
void
setOp(int opPos, int value)
Set the op at index to the given int.
String
toString()
Return the expression as a string for diagnostics.

Field Details

MAPINDEX_LENGTH

public static final int MAPINDEX_LENGTH
The length is always the opcode position + 1. Length is always expressed as the opcode+length bytes, so it is always 2 or greater.
Field Value:
1

Method Details

error

public void error(String msg,
                  Object[] args)
            throws javax.xml.transform.TransformerException
Tell the user of an error, and probably throw an exception.
Parameters:
msg - An error msgkey that corresponds to one of the constants found in XPATHErrorResources, which is a key for a format string.
args - An array of arguments represented in the format string, which may be null.

getArgLength

public int getArgLength(int opPos)
Get the length of an operation.
Parameters:
opPos - The position of the operation in the op map.
Returns:
The size of the operation.

getArgLengthOfStep

public int getArgLengthOfStep(int opPos)
Given a location step, get the length of that step.
Parameters:
opPos - Position of location step in op map.
Returns:
The length of the step.

getFirstChildPos

public static int getFirstChildPos(int opPos)
Go to the first child of a given operation.
Parameters:
opPos - position of operation.
Returns:
The position of the first child of the operation.

getFirstChildPosOfStep

public static int getFirstChildPosOfStep(int opPos)
Get the first child position of a given location step.
Parameters:
opPos - Position of location step in the location map.
Returns:
The first child position of the step.

getFirstPredicateOpPos

public int getFirstPredicateOpPos(int opPos)
            throws javax.xml.transform.TransformerException
Given an FROM_stepType position, return the position of the first predicate, if there is one, or else this will point to the end of the FROM_stepType. Example: int posOfPredicate = xpath.getNextOpPos(stepPos); boolean hasPredicates = OpCodes.OP_PREDICATE == xpath.getOp(posOfPredicate);
Parameters:
opPos - position of FROM_stepType op.
Returns:
position of predicate in FROM_stepType structure.

getNextOpPos

public int getNextOpPos(int opPos)
Given an operation position, return the end position, i.e. the beginning of the next operation.
Parameters:
opPos - An op position of an operation for which there is a size entry following.
Returns:
position of next operation in m_opMap.

getNextOpPos

public static int getNextOpPos(int[] opMap,
                               int opPos)
Given an operation position, return the end position, i.e. the beginning of the next operation.
Parameters:
opMap - The operations map.
opPos - index to operation, for which there is a size entry following.
Returns:
position of next operation in m_opMap.

getNextStepPos

public int getNextStepPos(int opPos)
Given a location step position, return the end position, i.e. the beginning of the next step.
Parameters:
opPos - the position of a location step.
Returns:
the position of the next location step.

getOp

public int getOp(int opPos)
Given an operation position, return the current op.
Parameters:
opPos - index into op map.
Returns:
the op that corresponds to the opPos argument.

getOpMap

public OpMapVector getOpMap()
Get the opcode list that describes the XPath operations. It contains operations codes and indexes into the m_tokenQueue. I use an array instead of a full parse tree in order to cut down on the number of objects created.
Returns:
An IntVector that is the opcode list that describes the XPath operations.

getPatternString

public String getPatternString()
Return the expression as a string for diagnostics.
Returns:
The expression string.

getStepLocalName

public String getStepLocalName(int opPosOfStep)
Get the local name of the step.
Parameters:
opPosOfStep - The position of the FROM_XXX step.
Returns:
OpCodes.EMPTY, OpCodes.ELEMWILDCARD, or the local name.

getStepNS

public String getStepNS(int opPosOfStep)
Get the namespace of the step.
Parameters:
opPosOfStep - The position of the FROM_XXX step.
Returns:
The step's namespace, NodeTest.WILD, or null for null namespace.

getStepTestType

public int getStepTestType(int opPosOfStep)
Get the test type of the step, i.e. NODETYPE_XXX value.
Parameters:
opPosOfStep - The position of the FROM_XXX step.
Returns:
NODETYPE_XXX value.

getToken

public Object getToken(int pos)
Get the XPath as a list of tokens.
Parameters:
pos - index into token queue.
Returns:
The token, normally a string.

getTokenQueue

public ObjectVector getTokenQueue()
Get the XPath as a list of tokens.
Returns:
ObjectVector of tokens.

getTokenQueueSize

public int getTokenQueueSize()
Get size of the token queue.
Returns:
The size of the token queue.

setOp

public void setOp(int opPos,
                  int value)
Set the op at index to the given int.
Parameters:
opPos - index into op map.
value - Value to set

toString

public String toString()
Return the expression as a string for diagnostics.
Returns:
The expression string.

Copyright B) 2005 Apache XML Project. All Rights Reserved.