org.quattor.pan.dml
Class AbstractOperation

java.lang.Object
  org.quattor.pan.dml.AbstractOperation

All Implemented Interfaces:

Operation

Direct Known Subclasses:

Add, Assign, BitAnd, BitIOR, BitNot, BitXOR, BuiltInFunction, Div, DML, For, Foreach, Function, IfElse, ListVariable, LogicalAnd, LogicalEQ, LogicalGE, LogicalGT, LogicalLE, LogicalLT, LogicalNE, LogicalNot, LogicalOr, Mod, Mult, SetValue, Sub, UnaryMinus, UnaryPlus, Variable, While

public abstract class AbstractOperation
extends java.lang.Object
implements Operation

Abstract class which implements the Operation interface and provides some functionality common to all DML components.

Author:

loomis

Field Summary

protected Operation[]	ops Array of arguments (as operations) for this operation.
protected SourceRange	sourceRange Source location of this operation and its arguments.

Constructor Summary

AbstractOperation(SourceRange sourceRange, Operation... operations)
Set the source location information and arguments for this operation.

Method Summary

protected Element[]	calculateArgs(Context context) A utility method which calls execute on each of this operation's arguments and returns an array of the results.
protected Term[]	calculateTerms(Context context) A utility method that creates a list of terms from the given arguments.
void	checkInvalidSelfContext() Default implementation recursively calls this method on all of the contained operations (arguments).
void	checkRestrictedContext() Default implementation recursively calls this method on all of the contained operations (arguments).
abstract Element	execute(Context context) Execute this operation within the given context.
Operation[]	getOperations() Allow a copy of the raw operations to be retrieved.
SourceRange	getSourceRange() Retrieve the source information from this operation.
java.lang.String	toString() Default string representation of an operation is the class' simple name.

Methods inherited from class java.lang.Object

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

Field Detail

sourceRange

protected final SourceRange sourceRange

Source location of this operation and its arguments.

ops

protected final Operation[] ops

Array of arguments (as operations) for this operation.

Constructor Detail

AbstractOperation

public AbstractOperation(SourceRange sourceRange,
                         Operation... operations)

Set the source location information and arguments for this operation.

Parameters:

sourceRange - source location of this operation and arguments

operations - list of arguments (as operations) for this operation

Method Detail

execute

public abstract Element execute(Context context)
                         throws EvaluationException

Description copied from interface: Operation

Execute this operation within the given context. If an error occurs, an EvaluationException will be thrown with the details.

Specified by:

execute in interface Operation

Parameters:

context - evaluation context for the statement

Returns:

Element produced by running operation

Throws:

EvaluationException - if an error occurs during processing

checkRestrictedContext

public void checkRestrictedContext()
                            throws SyntaxException

Default implementation recursively calls this method on all of the contained operations (arguments). Subclasses that cannot appear in a restricted context (array indices or function arguments) should override this method and throw a SyntaxException.

Specified by:

checkRestrictedContext in interface Operation

Throws:

SyntaxException - if operation cannot appear in restricted context

checkInvalidSelfContext

public void checkInvalidSelfContext()
                             throws SyntaxException

Default implementation recursively calls this method on all of the contained operations (arguments). Subclasses that reference SELF should override this method and throw a SyntaxException.

Specified by:

checkInvalidSelfContext in interface Operation

Throws:

SyntaxException - if operation references SELF

calculateArgs

protected Element[] calculateArgs(Context context)
                           throws EvaluationException

A utility method which calls execute on each of this operation's arguments and returns an array of the results.

Parameters:

context - evaluation context to use

Returns:

array of the results of executing the arguments

Throws:

EvaluationException

calculateTerms

protected Term[] calculateTerms(Context context)
                         throws EvaluationException

A utility method that creates a list of terms from the given arguments.

Parameters:

context - evaluation context to use

Returns:

array of terms calculated from the operations

Throws:

EvaluationException - if any error occurs when evaluating the arguments or if the resulting value is not a valid Term

getSourceRange

public SourceRange getSourceRange()

Retrieve the source information from this operation. The SourceRange is available to subclasses as a protected field, so subclasses can access the value directly.

Returns:

SourceRange giving location of this operation and its arguments

getOperations

public Operation[] getOperations()

Allow a copy of the raw operations to be retrieved.

toString

public java.lang.String toString()

Default string representation of an operation is the class' simple name.

Overrides:

toString in class java.lang.Object

Returns:

string of class' simple name