Compiler (Red Hat JBoss Enterprise Application Platform 7.1.0.GA public API)

java.lang.Object
- org.apache.xpath.compiler.OpMap
- - org.apache.xpath.compiler.Compiler

```
public class Compiler
extends OpMap
```
An instance of this class compiles an XPath string expression into a Expression object. This class compiles the string into a sequence of operation codes (op map) and then builds from that into an Expression tree.

Field Summary
- Fields inherited from class org.apache.xpath.compiler.OpMap
  m_currentPattern, MAPINDEX_LENGTH

Constructor Summary

Constructors
Constructor and Description
`Compiler()` Construct a Compiler instance that has a null error listener and a null source locator.
`Compiler(ErrorListener errorHandler, SourceLocator locator, FunctionTable fTable)` Construct a Compiler object with a specific ErrorListener and SourceLocator where the expression is located.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected Expression`	`and(int opPos)` Compile an 'and' operation.
`protected Expression`	`arg(int opPos)` Compile a function argument.
`void`	`assertion(boolean b, String msg)` Tell the user of an assertion error, and probably throw an exception.
`protected Expression`	`bool(int opPos)` Compile a 'boolean(...)' operation.
`Expression`	`compile(int opPos)` Execute the XPath object from a given opcode position.
`int`	`countPredicates(int opPos)` Count the number of predicates in the step.
`protected Expression`	`div(int opPos)` Compile a 'div' operation.
`protected Expression`	`equals(int opPos)` Compile a '=' operation.
`void`	`error(String msg, Object[] args)` Tell the user of an error, and probably throw an exception.
`Expression[]`	`getCompiledPredicates(int opPos)` Compile a zero or more predicates for a given match pattern.
`int`	`getLocationPathDepth()` Get the level of the location path or union being constructed.
`PrefixResolver`	`getNamespaceContext()` Get the current namespace context for the xpath.
`int`	`getWhatToShow(int opPos)` Get a `NodeFilter` bit set that tells what to show for a given node test.
`protected Expression`	`group(int opPos)` Compile an expression group.
`protected Expression`	`gt(int opPos)` Compile a '>' operation.
`protected Expression`	`gte(int opPos)` Compile a '>=' operation.
`protected Expression`	`literal(int opPos)` Compile a literal string value.
`Expression`	`locationPath(int opPos)` Compile a location path.
`Expression`	`locationPathPattern(int opPos)` Compile a location match pattern unit expression.
`protected Expression`	`lt(int opPos)` Compile a '<' operation.
`protected Expression`	`lte(int opPos)` Compile a '<=' operation.
`protected Expression`	`matchPattern(int opPos)` Compile an entire match pattern expression.
`protected Expression`	`minus(int opPos)` Compile a '-' operation.
`protected Expression`	`mod(int opPos)` Compile a 'mod' operation.
`protected Expression`	`mult(int opPos)` Compile a '*' operation.
`protected Expression`	`neg(int opPos)` Compile a unary '-' operation.
`protected Expression`	`notequals(int opPos)` Compile a '!=' operation.
`protected Expression`	`number(int opPos)` Compile a 'number(...)' operation.
`protected Expression`	`numberlit(int opPos)` Compile a literal number value.
`protected Expression`	`or(int opPos)` Compile an 'or' operation.
`protected Expression`	`plus(int opPos)` Compile a '+' operation.
`Expression`	`predicate(int opPos)` Compile a location step predicate expression.
`void`	`setNamespaceContext(PrefixResolver pr)` Set the current namespace context for the xpath.
`protected StepPattern`	`stepPattern(int opPos, int stepCount, StepPattern ancestorPattern)` Compile a step pattern unit expression, used for both location paths and match patterns.
`protected Expression`	`string(int opPos)` Compile a 'string(...)' operation.
`protected Expression`	`union(int opPos)` Compile a location path union.
`protected Expression`	`variable(int opPos)` Compile a variable reference.
`void`	`warn(String msg, Object[] args)` Warn the user of an problem.

Methods inherited from class org.apache.xpath.compiler.OpMap
getArgLength, getArgLengthOfStep, getFirstChildPos, getFirstChildPosOfStep, getFirstPredicateOpPos, getNextOpPos, getNextOpPos, getNextStepPos, getOp, getOpMap, getPatternString, getStepLocalName, getStepNS, getStepTestType, getToken, getTokenQueue, getTokenQueueSize, setOp, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Compiler
```
public Compiler(ErrorListener errorHandler,
                SourceLocator locator,
                FunctionTable fTable)
```
    Construct a Compiler object with a specific ErrorListener and SourceLocator where the expression is located.
    
    Parameters:
    
    errorHandler - Error listener where messages will be sent, or null if messages should be sent to System err.
    
    locator - The location object where the expression lives, which may be null, but which, if not null, must be valid over the long haul, in other words, it will not be cloned.
    
    fTable - The FunctionTable object where the xpath build-in functions are stored.
  - Compiler
```
public Compiler()
```
    Construct a Compiler instance that has a null error listener and a null source locator.
- Method Detail
  - compile
```
public Expression compile(int opPos)
                   throws TransformerException
```
    Execute the XPath object from a given opcode position.
    
    Parameters:
    
    opPos - The current position in the xpath.m_opMap array.
    
    Returns:
    
    The result of the XPath.
    
    Throws:
    
    TransformerException - if there is a syntax or other error.
  - or
```
protected Expression or(int opPos)
                 throws TransformerException
```
    Compile an 'or' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Or instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - and
```
protected Expression and(int opPos)
                  throws TransformerException
```
    Compile an 'and' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to And instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - notequals
```
protected Expression notequals(int opPos)
                        throws TransformerException
```
    Compile a '!=' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to NotEquals instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - equals
```
protected Expression equals(int opPos)
                     throws TransformerException
```
    Compile a '=' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Equals instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - lte
```
protected Expression lte(int opPos)
                  throws TransformerException
```
    Compile a '<=' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Lte instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - lt
```
protected Expression lt(int opPos)
                 throws TransformerException
```
    Compile a '<' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Lt instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - gte
```
protected Expression gte(int opPos)
                  throws TransformerException
```
    Compile a '>=' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Gte instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - gt
```
protected Expression gt(int opPos)
                 throws TransformerException
```
    Compile a '>' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Gt instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - plus
```
protected Expression plus(int opPos)
                   throws TransformerException
```
    Compile a '+' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Plus instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - minus
```
protected Expression minus(int opPos)
                    throws TransformerException
```
    Compile a '-' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Minus instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - mult
```
protected Expression mult(int opPos)
                   throws TransformerException
```
    Compile a '*' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Mult instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - div
```
protected Expression div(int opPos)
                  throws TransformerException
```
    Compile a 'div' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Div instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - mod
```
protected Expression mod(int opPos)
                  throws TransformerException
```
    Compile a 'mod' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Mod instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - neg
```
protected Expression neg(int opPos)
                  throws TransformerException
```
    Compile a unary '-' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Neg instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - string
```
protected Expression string(int opPos)
                     throws TransformerException
```
    Compile a 'string(...)' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to String instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - bool
```
protected Expression bool(int opPos)
                   throws TransformerException
```
    Compile a 'boolean(...)' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Bool instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - number
```
protected Expression number(int opPos)
                     throws TransformerException
```
    Compile a 'number(...)' operation.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Number instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - literal
```
protected Expression literal(int opPos)
```
    Compile a literal string value.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to XString instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - numberlit
```
protected Expression numberlit(int opPos)
```
    Compile a literal number value.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to XNumber instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - variable
```
protected Expression variable(int opPos)
                       throws TransformerException
```
    Compile a variable reference.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to Variable instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - group
```
protected Expression group(int opPos)
                    throws TransformerException
```
    Compile an expression group.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to the contained expression.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - arg
```
protected Expression arg(int opPos)
                  throws TransformerException
```
    Compile a function argument.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to the argument expression.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - union
```
protected Expression union(int opPos)
                    throws TransformerException
```
    Compile a location path union. The UnionPathIterator itself may create LocPathIterator children.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to LocPathIterator instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - getLocationPathDepth
```
public int getLocationPathDepth()
```
    Get the level of the location path or union being constructed.
    
    Returns:
    
    0 if it is a top-level path.
  - locationPath
```
public Expression locationPath(int opPos)
                        throws TransformerException
```
    Compile a location path. The LocPathIterator itself may create AxesWalker children.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to LocPathIterator instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - predicate
```
public Expression predicate(int opPos)
                     throws TransformerException
```
    Compile a location step predicate expression.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    the contained predicate expression.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - matchPattern
```
protected Expression matchPattern(int opPos)
                           throws TransformerException
```
    Compile an entire match pattern expression.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to UnionPattern instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - locationPathPattern
```
public Expression locationPathPattern(int opPos)
                               throws TransformerException
```
    Compile a location match pattern unit expression.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    Returns:
    
    reference to StepPattern instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - getWhatToShow
```
public int getWhatToShow(int opPos)
```
    Get a NodeFilter bit set that tells what to show for a given node test.
    
    Parameters:
    
    opPos - the op map position for the location step.
    
    Returns:
    
    NodeFilter bit set that tells what to show for a given node test.
  - stepPattern
```
protected StepPattern stepPattern(int opPos,
                                  int stepCount,
                                  StepPattern ancestorPattern)
                           throws TransformerException
```
    Compile a step pattern unit expression, used for both location paths and match patterns.
    
    Parameters:
    
    opPos - The current position in the m_opMap array.
    
    stepCount - The number of steps to expect.
    
    ancestorPattern - The owning StepPattern, which may be null.
    
    Returns:
    
    reference to StepPattern instance.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - getCompiledPredicates
```
public Expression[] getCompiledPredicates(int opPos)
                                   throws TransformerException
```
    Compile a zero or more predicates for a given match pattern.
    
    Parameters:
    
    opPos - The position of the first predicate the m_opMap array.
    
    Returns:
    
    reference to array of Expression instances.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - countPredicates
```
public int countPredicates(int opPos)
                    throws TransformerException
```
    Count the number of predicates in the step.
    
    Parameters:
    
    opPos - The position of the first predicate the m_opMap array.
    
    Returns:
    
    The number of predicates for this step.
    
    Throws:
    
    TransformerException - if a error occurs creating the Expression.
  - warn
```
public void warn(String msg,
                 Object[] args)
          throws TransformerException
```
    Warn the user of an problem.
    
    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.
    
    Throws:
    
    TransformerException - if the current ErrorListoner determines to throw an exception.
  - assertion
```
public void assertion(boolean b,
                      String msg)
```
    Tell the user of an assertion error, and probably throw an exception.
    
    Parameters:
    
    b - If false, a runtime exception will be thrown.
    
    msg - The assertion message, which should be informative.
    
    Throws:
    
    RuntimeException - if the b argument is false.
  - error
```
public void error(String msg,
                  Object[] args)
           throws TransformerException
```
    Tell the user of an error, and probably throw an exception.
    
    Overrides:
    
    error in class OpMap
    
    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.
    
    Throws:
    
    TransformerException - if the current ErrorListoner determines to throw an exception.
  - getNamespaceContext
```
public PrefixResolver getNamespaceContext()
```
    Get the current namespace context for the xpath.
    
    Returns:
    
    The current prefix resolver, *may* be null, though hopefully not.
  - setNamespaceContext
```
public void setNamespaceContext(PrefixResolver pr)
```
    Set the current namespace context for the xpath.
    
    Parameters:
    
    pr - The resolver for prefixes in the XPath expression.

Class Compiler

Field Summary

Fields inherited from class org.apache.xpath.compiler.OpMap

Constructor Summary

Method Summary

Methods inherited from class org.apache.xpath.compiler.OpMap

Methods inherited from class java.lang.Object

Constructor Detail

Compiler

Compiler

Method Detail

compile

or

and

notequals

equals

lte

lt

gte

gt

plus

minus

mult

div

mod

neg

string

bool

number

literal

numberlit

variable

group

arg

union

getLocationPathDepth

locationPath

predicate

matchPattern

locationPathPattern

getWhatToShow

stepPattern

getCompiledPredicates

countPredicates

warn

assertion

error

getNamespaceContext

setNamespaceContext