/*******************************************************************************
* Copyright (c) 2006, 2015 Oracle and/or its affiliates. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation
*
******************************************************************************/
package org.eclipse.persistence.jpa.jpql.parser;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import org.eclipse.persistence.jpa.jpql.Assert;
import org.eclipse.persistence.jpa.jpql.JPAVersion;
/**
* This registry contains the necessary information used by Hermes parser. When parsing a JPQL query,
* the {@link JPQLGrammar} given to {@link JPQLExpression} will give access to this registry.
* <p>
* Provisional API: This interface is part of an interim API that is still under development and
* expected to change significantly before reaching stability. It is available at this early stage
* to solicit feedback from pioneering adopters on the understanding that any code that uses this
* API will almost certainly be broken (repeatedly) as the API evolves.
*
* @see JPQLGrammar
* @see ExpressionFactory
* @see JPQLQueryBNF
*
* @version 2.5
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings("nls")
public class ExpressionRegistry {
/**
* The map of {@link ExpressionFactory ExpressionFactories} that have been registered and
* required for parsing a JPQL query, they are mapped with their unique identifier.
*/
private Map<String, ExpressionFactory> expressionFactories;
/**
* The set of the JPQL identifiers defined by the grammar.
*/
private Map<String, IdentifierRole> identifiers;
/**
* This table specify in which JPA version the identifiers was introduced.
*/
private Map<String, JPAVersion> identifierVersions;
/**
* The {@link JPQLQueryBNF} unique identifiers mapped to the only instance of the BNF rule.
*/
private Map<String, JPQLQueryBNF> queryBNFs;
/**
* Creates the only instance of <code>ExpressionRegistry</code>.
*/
public ExpressionRegistry() {
super();
initialize();
}
/**
* Adds to the given query BNF a child BNF.
*
* @param queryBNFId The unique identifier of the parent BNF to add a child BNF
* @param childQueryBNFId The unique identifier of the child to add to the parent BNF
* @exception NullPointerException The {@link JPQLQueryBNF} identified by the given ID does not exist
*/
public void addChildBNF(String queryBNFId, String childQueryBNFId) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.registerChild(childQueryBNFId);
}
/**
* Adds to the given unique identifier of an {@link ExpressionFactory} to the given query BNF.
*
* @param queryBNFId The unique identifier of the parent BNF
* @param childExpressionFactoryId The unique identifier of the {@link ExpressionFactory} to add
* to the given query BNF
* @exception NullPointerException The {@link JPQLQueryBNF} identified by the given ID does not exist
*/
public void addChildFactory(String queryBNFId, String childExpressionFactoryId) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.registerExpressionFactory(childExpressionFactoryId);
}
/**
* Adds the given JPQL identifier to this factory.
*
* @param expressionFactoryId The unique identifier of the {@link ExpressionFactory} to add more
* JPQL identifiers
* @param identifier The JPQL identifier this factory will parse
*/
public void addIdentifier(String expressionFactoryId, String identifier) {
getExpressionFactory(expressionFactoryId).addIdentifier(identifier);
}
/**
* Adds the given JPQL identifiers to this factory.
*
* @param expressionFactoryId The unique identifier of the {@link ExpressionFactory} to add more
* JPQL identifiers
* @param identifiers The JPQL identifiers this factory will parse
*/
public void addIdentifiers(String expressionFactoryId, String... identifiers) {
getExpressionFactory(expressionFactoryId).addIdentifiers(identifiers);
}
/**
* Retrieves the {@link ExpressionFactory} that is responsible for creating the {@link Expression}
* object that represents the given JPQL identifier.
*
* @param identifier The JPQL identifier for which its factory is searched
* @return Either the {@link ExpressionFactory} that creates the {@link Expression} or
* <code>null</code> if none was found
*/
public ExpressionFactory expressionFactoryForIdentifier(String identifier) {
identifier = identifier.toUpperCase();
if (Expression.SELECT.equalsIgnoreCase(identifier)) {
return getExpressionFactory(SimpleSelectStatementFactory.ID);
}
for (ExpressionFactory expressionFactory : expressionFactories.values()) {
boolean found = Arrays.binarySearch(expressionFactory.identifiers(), identifier) > -1;
if (found) {
return expressionFactory;
}
}
return null;
}
/**
* Retrieves the registered {@link ExpressionFactory} that was registered for the given unique identifier.
*
* @param expressionFactoryId The unique identifier of the {@link ExpressionFactory} to retrieve
* @return The {@link ExpressionFactory} mapped with the given unique identifier
*/
public ExpressionFactory getExpressionFactory(String expressionFactoryId) {
return expressionFactories.get(expressionFactoryId);
}
/**
* Retrieves the {@link IdentifierRole} of the given JPQL identifier. A role helps to describe
* the purpose of the identifier in a JPQL query.
*
* @param identifier The JPQL identifier for which its role is returned
* @return The {@link IdentifierRole} of the given JPQL identifier
*/
public IdentifierRole getIdentifierRole(String identifier) {
return identifiers.get(identifier.toUpperCase());
}
/**
* Returns the JPQL identifiers that are supported by the {@link JPQLGrammar JPQL grammar}.
*
* @return The supported JPQL identifiers
*/
public Set<String> getIdentifiers() {
return Collections.unmodifiableSet(identifiers.keySet());
}
/**
* Retrieves the JPQL identifiers that are supported by the BNF rule with the given unique
* identifier. The JPQL identifiers are retrieved by scanning the {@link ExpressionFactory}
* registered with the BNF rule and its child BNF rules.
*
* @return The list of JPQL identifiers that are supported by a BNF rule
*/
public Iterable<String> getIdentifiers(String queryBNFId) {
return getQueryBNF(queryBNFId).getIdentifiers();
}
/**
* Retrieves the JPA version in which the identifier was first introduced.
*
* @return The version in which the identifier was introduced
*/
public JPAVersion getIdentifierVersion(String identifier) {
JPAVersion version = identifierVersions.get(identifier.toUpperCase());
return (version != null) ? version : JPAVersion.VERSION_1_0;
}
/**
* Retrieves the BNF object that was registered for the given unique identifier.
*
* @param queryBNFId The unique identifier of the {@link JPQLQueryBNF} to retrieve
* @return The {@link JPQLQueryBNF} representing a section of the grammar
*/
public JPQLQueryBNF getQueryBNF(String queryBNFId) {
return queryBNFs.get(queryBNFId);
}
/**
* Instantiates the only instance of various API used by the parser.
*/
protected void initialize() {
queryBNFs = new HashMap<String, JPQLQueryBNF>();
identifiers = new HashMap<String, IdentifierRole>();
expressionFactories = new HashMap<String, ExpressionFactory>();
identifierVersions = new HashMap<String, JPAVersion>();
}
/**
* Determines if the given word is a JPQL identifier. The check is case insensitive.
*
* @param text The string value to test if it's a JPQL identifier based on what is registered
* with this <code>ExpressionRegistry</code>
* @return <code>true</code> if the word is an identifier, <code>false</code> otherwise
*/
public boolean isIdentifier(String text) {
return identifiers.containsKey(text.toUpperCase());
}
/**
* Registers the given {@link JPQLQueryBNF}. The BNF will be registered using its unique
* identifier.
*
* @param queryBNF The {@link JPQLQueryBNF} to store
* @exception NullPointerException The {@link JPQLQueryBNF} cannot be <code>null</code>
*/
public void registerBNF(JPQLQueryBNF queryBNF) {
Assert.isNotNull(queryBNF, "The JPQLQueryBNF cannot be null");
queryBNFs.put(queryBNF.getId(), queryBNF);
queryBNF.setExpressionRegistry(this);
}
/**
* Registers the given {@link ExpressionFactory} by storing it for all its identifiers.
*
* @param expressionFactory The {@link ExpressionFactory} to store
* @exception NullPointerException The {@link ExpressionFactory} cannot be <code>null</code>
*/
public void registerFactory(ExpressionFactory expressionFactory) {
Assert.isNotNull(expressionFactory, "The ExpressionFactory cannot be null");
expressionFactories.put(expressionFactory.getId(), expressionFactory);
expressionFactory.setExpressionRegistry(this);
}
/**
* Registers the {@link IdentifierRole} for the given JPQL identifier.
*
* @param identifier The JPQL identifier to register its role within a JPQL query
* @param role The role of the given JPQL identifier
* @exception NullPointerException The JPQL identifier and the {@link IdentifierRole} cannot be
* <code>null</code>
*/
public void registerIdentifierRole(String identifier, IdentifierRole role) {
Assert.isNotNull(identifier, "The JPQL identifier cannot be null");
Assert.isNotNull(role, "The IdentifierRole cannot be null");
identifiers.put(identifier, role);
}
/**
* Registers the {@link JPAVersion} for which the given JPQL identifier was defined.
*
* @param identifier The JPQL identifier to register in which version it was added to the grammar
* @param version The version when the JPQL identifier was added to the grammar
* @exception NullPointerException The JPQL identifier and the {@link JPAVersion} cannot be
* <code>null</code>
*/
public void registerIdentifierVersion(String identifier, JPAVersion version) {
Assert.isNotNull(identifier, "The JPQL identifier cannot be null");
Assert.isNotNull(version, "The JPAVersion cannot be null");
identifierVersions.put(identifier, version);
}
/**
* When parsing the query and no {@link JPQLQueryBNF JPQLQueryBNFs} can help to parse the query,
* then it will fall back on the given one.
*
* @param queryBNFId The unique identifier of the BNF to modify its fallback BNF unique identifier
* @param fallbackBNFId The unique identifier of the {@link JPQLQueryBNF} to use in the last resort
* @exception NullPointerException The {@link JPQLQueryBNF} identified by the given ID does not exist
*/
public void setFallbackBNFId(String queryBNFId, String fallbackBNFId) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.setFallbackBNFId(queryBNFId);
}
/**
* Sets the unique identifier of the {@link ExpressionFactory} to use when the fall back BNF
* ID is not <code>null</code>. This will be used to parse a portion of the query when the
* registered {@link ExpressionFactory expression factories} cannot parse it.
* <p>
* Note: This method is only called if {@link JPQLQueryBNF#getFallbackBNFId() JPQLQueryBNF.
* getFallbackBNFId()} does not return <code>null</code>.
*
* @param queryBNFId The unique identifier of the BNF to modify its fallback expression factory
* unique identifier
* @exception NullPointerException The {@link JPQLQueryBNF} identified by the given ID does not exist
*/
public void setFallbackExpressionFactoryId(String queryBNFId, String fallbackExpressionFactoryId) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.setFallbackExpressionFactoryId(fallbackExpressionFactoryId);
}
/**
* Determines whether the <code>Expression</code> handles a collection of sub-expressions that
* are separated by commas.
*
* @param queryBNFId The unique identifier of the {@link JPQLQueryBNF}
* @param handleCollection <code>true</code> if the sub-expression to parse might have several
* sub-expressions separated by commas; <code>false</code> otherwise
*/
public void setHandleCollection(String queryBNFId, boolean handleCollection) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.setHandleCollection(handleCollection);
}
/**
* Sets whether the BNF with the given ID supports nested array or not. A nested array is a sub-
* expression with its child being a collection expression: (item_1, item_2, ..., item_n).
*
* @param queryBNFId The unique identifier of the {@link JPQLQueryBNF}
* @param handleNestedArray <code>true</code> if the expression represented by this BNF can be
* a nested array; <code>false</code> otherwise
* @since 2.5
*/
public void setHandleNestedArray(String queryBNFId, boolean handleNestedArray) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.setHandleNestedArray(handleNestedArray);
}
/**
* Sets whether the query BNF with the given ID handles parsing a sub-expression, i.e. parsing an
* expression encapsulated by parenthesis. Which in fact would be handled by the fallback {@link
* ExpressionFactory}. The default behavior is to not handle it.
* <p>
* A good example for using this option is when an {@link Expression} cannot use any {@link
* ExpressionFactory} for creating a child object, parsing will use the fallback {@link
* ExpressionFactory}, if one was specified. So when this is set to <code>true</code>, the
* fallback {@link ExpressionFactory} will be immediately invoked.
* <p>
* Let's say we want to parse "SELECT e FROM (SELECT a FROM Address a) e", {@link FromClause}
* cannot use a factory for parsing the entity name (that's what usually the <code>FROM</code>
* clause has) so it uses the fallback factory to create {@link IdentificationVariableDeclaration}.
* Then <code>IdentificationVariableDeclaration</code> also cannot use any factory to create its
* child object so it uses the fallback factory to create {@link RangeVariableDeclaration}.
* By changing the status of for handling the sub-expression for the BNFs for those objects, then
* a subquery can be created by <code>RangeVariableDeclaration</code>.
*
* <pre><code>FromClause
* |- IdentificationVariableDeclaration
* |- RangeVariableDeclaration
* |- SubExpression(subquery)</code></pre>
*
* In order to get this working, the following would have to be done into the grammar:
*
* <pre><code> public class MyJPQLGrammar extends AbstractJPQLGrammar {
* @Override
* protected void initializeBNFs() {
* setHandleSubExpression(InternalFromClauseBNF.ID, true);
* setHandleSubExpression(InternalSimpleFromClauseBNF.ID, true);
* setHandleSubExpression(IdentificationVariableDeclarationBNF.ID, true);
* setHandleSubExpression(RangeVariableDeclarationBNF.ID, true);
* }
* }</code></pre>
*
* @param queryBNFId The unique identifier of the {@link JPQLQueryBNF}
* @param handleSubExpression <code>true</code> to let the creation of a sub-expression be
* created by the fallback {@link ExpressionFactory} registered with this BNF; <code>false</code>
* otherwise (which is the default value)
*/
public void setHandleSubExpression(String queryBNFId, boolean handleSubExpression) {
JPQLQueryBNF queryBNF = queryBNFs.get(queryBNFId);
Assert.isNotNull(queryBNF, "The JPQLQueryBNF identified with '" + queryBNFId + "' does not exist.");
queryBNF.setHandleSubExpression(handleSubExpression);
}
/**
* Unregisters the given {@link JPQLQueryBNF}.
*
* @param queryBNF The {@link JPQLQueryBNF} to unregister
* @exception NullPointerException The {@link JPQLQueryBNF} cannot be <code>null</code>
*/
public void unregisterBNF(JPQLQueryBNF queryBNF) {
Assert.isNotNull(queryBNF, "The JPQLQueryBNF cannot be null");
queryBNFs.remove(queryBNF.getId());
queryBNF.setExpressionRegistry(null);
}
}