openjava.ptree.util
Class QueryExpander

java.lang.Object
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  +--openjava.ptree.util.ParseTreeVisitor
        |
        +--openjava.ptree.util.EvaluationShuttle
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              +--openjava.ptree.util.ScopeHandler
                    |
                    +--openjava.ptree.util.QueryExpander

Direct Known Subclasses:

OJQueryExpander

public abstract class QueryExpander

extends ScopeHandler

QueryExpander is a ParseTreeVisitor which, as it passes over a parse tree, converts QueryExpressions into regular java constructs.

The non-abstract derived class OJQueryExpander does this by converting the expression to a tree of SaffronRel nodes, and using an optimizer (SaffronPlanner) to choose the optimal java implementation.

Field Summary

Fields inherited from class openjava.ptree.util.ScopeHandler

Fields inherited from class openjava.ptree.util.EvaluationShuttle

Constructor Summary

QueryExpander(Environment env)

Method Summary

Expression	evaluateDown(BinaryExpression p) Expands in union, minus, and intersect.
Expression	evaluateDown(CastExpression p)
Statement	evaluateDown(ForStatement p) Expand 'for (<> in <>) ...'.
Expression	evaluateDown(InsertExpression p)
Expression	evaluateDown(MethodCall p) Expands connection.contentsAsArray("qualifier","name"), which was probably generated by expanding connection.name.
Expression	evaluateDown(QueryExpression p)
Expression	evaluateDown(UnaryExpression p) Expands exists.
protected abstract Expression	expandExpression(Expression p) Converts an Expression into a java expression which returns an array.
protected abstract Statement	expandForIn(Variable var, Expression p, StatementList body) Converts an Expression of the form for (variable in exp) { body } into a regular java Statement.
boolean	isRelational(Expression p)

Methods inherited from class openjava.ptree.util.ScopeHandler

evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, pop, push, pushClosedEnvironment

Methods inherited from class openjava.ptree.util.EvaluationShuttle

evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateDown, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, evaluateUp, getEnvironment, setEnvironment, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class openjava.ptree.util.ParseTreeVisitor

visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryExpander

public QueryExpander(Environment env)

Method Detail

evaluateDown

public Expression evaluateDown(QueryExpression p)
                        throws ParseTreeException

Overrides:

evaluateDown in class ScopeHandler

ParseTreeException

evaluateDown

public Expression evaluateDown(InsertExpression p)
                        throws ParseTreeException

Overrides:

evaluateDown in class EvaluationShuttle

ParseTreeException

isRelational

public boolean isRelational(Expression p)

evaluateDown

public Expression evaluateDown(CastExpression p)
                        throws ParseTreeException

Overrides:

evaluateDown in class EvaluationShuttle

ParseTreeException

evaluateDown

public Statement evaluateDown(ForStatement p)
                       throws ParseTreeException

Expand 'for (<> in <>) ...'.

Overrides:

evaluateDown in class ScopeHandler

ParseTreeException

evaluateDown

public Expression evaluateDown(BinaryExpression p)
                        throws ParseTreeException

Expands in union, minus, and intersect.

Overrides:

evaluateDown in class EvaluationShuttle

ParseTreeException

evaluateDown

public Expression evaluateDown(UnaryExpression p)
                        throws ParseTreeException

Expands exists.

Overrides:

evaluateDown in class EvaluationShuttle

ParseTreeException

evaluateDown

public Expression evaluateDown(MethodCall p)
                        throws ParseTreeException

Expands connection.contentsAsArray("qualifier","name"), which was probably generated by expanding connection.name.

Overrides:

evaluateDown in class EvaluationShuttle

ParseTreeException

expandExpression

protected abstract Expression expandExpression(Expression p)

Converts an Expression into a java expression which returns an array.

expandForIn

protected abstract Statement expandForIn(Variable var,
                                         Expression p,
                                         StatementList body)

Converts an Expression of the form for (variable in exp) { body } into a regular java Statement.