Package org.datanucleus.query.compiler

Package handling the compilation of queries.

See: Description

Interface Summary

Interface	Description
CompilationOptimiser	Interface to be implemented by an "optimiser" for the query compilation process.
Parser	Interface for a parser of a query.
QueryCompilationCache	Cache for query compilations (generic).
Symbol	A symbol in a query.
SymbolResolver	Interface for use in the resolution of symbols during query compilation.

Class Summary

Class	Description
AbstractParser	Abstract query parser.
AbstractQueryCompilationCache	Abstract representation of a cache of generic query compilations.
AbstractSymbolResolver	Base symbol resolver, to be extended for particular query languages.
JavaQueryCompiler	Typical implementation of a compiler for a java-based query language.
JavaxCacheQueryCompilationCache	Query compilation cache using javax.cache for implementation.
JDOQLCompiler	Implementation of a compiler for JDOQL (JSR0012, JSR0243).
JDOQLParser	Implementation of a parser for JDOQL query language.
JDOQLSymbolResolver	Symbol resolver for JDOQL.
JPQLCompiler	Implementation of a compiler for JPQL (JSR0220, JSR0317).
JPQLParser	Implementation of a parser for JPQL query language.
JPQLSymbolResolver	Symbol resolver for JPQL.
Lexer	Lexer for a Query.
NavigationNullCompilationOptimiser	Optimiser for query compilation that searches for navigation through relations, and adds "not null" checks.
Node	Representation of a node in a tree of nodes.
ParameterNode	Node representing a parameter.
PropertySymbol	Symbol representing a property/identifier in a query.
QueryCompilation	Representation of the components of a compiled java "string-based" query.
SoftQueryCompilationCache	Soft-reference implementation of a generic query compilation cache.
StrongQueryCompilationCache	Strong-reference implementation of a generic query compilation cache.
SymbolTable	Table of symbols in a query.
VarThisCompilationOptimiser	Optimiser for query compilation that searches for variable equality like "var == this".
WeakQueryCompilationCache	Weak-reference implementation of a generic query compilation cache.

Enum Summary

Enum	Description
CompilationComponent	Enum defining the component of a query being compiled.
NodeType	Enum of node types.

Package org.datanucleus.query.compiler Description

Package handling the compilation of queries. Provides compilation of "string-based" queries. Provides handling for different query languages such as JDOQL and JPQL. Compilation of a string-based query goes through two steps.

1. Parse of the string converting each component of the query into a Node tree
2. Compilation of the Node tree into an expression tree

From this tree the evaluation process can be configured to convert it into the native query language for the datastore; this part is handled within each datastore plugin. From this tree an in-memory evaluation can be performed. This is provided in the org.datanucleus.query.evaluator package and subpackage(s).