| /* |
| * Copyright (c) 2011, 2021 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 v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // Contributors: |
| // Oracle - initial API and implementation |
| // |
| package org.eclipse.persistence.jpa.jpql.parser; |
| |
| import org.eclipse.persistence.jpa.jpql.JPAVersion; |
| |
| /** |
| * <p>The abstract definition of a {@link JPQLGrammar}. The grammar defines how a JPQL query is parsed, |
| * which is based on the BNF defined for that grammar.</p> |
| * |
| * <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.</p> |
| * |
| * @version 2.5 |
| * @since 2.4 |
| * @author Pascal Filion |
| */ |
| public abstract class AbstractJPQLGrammar implements JPQLGrammar { |
| |
| /** |
| * The base {@link JPQLGrammar} this one extends or <code>null</code> if this is the base grammar. |
| */ |
| private JPQLGrammar jpqlGrammar; |
| |
| /** |
| * The registry contains the {@link JPQLQueryBNF JPQLQueryBNFs} and the {@link ExpressionFactory |
| * ExpressionFactories} and the support JPQL identifiers. |
| */ |
| private ExpressionRegistry registry; |
| |
| /** |
| * Creates a new <code>AbstractJPQLGrammar</code>. |
| */ |
| protected AbstractJPQLGrammar() { |
| super(); |
| initialize(); |
| } |
| |
| /** |
| * Creates a new <code>AbstractJPQLGrammar</code>. |
| * |
| * @param jpqlGrammar The {@link JPQLGrammar} to extend with the content of this one without |
| * instantiating the base {@link JPQLGrammar} |
| */ |
| protected AbstractJPQLGrammar(AbstractJPQLGrammar jpqlGrammar) { |
| super(); |
| initialize(jpqlGrammar); |
| } |
| |
| /** |
| * 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 |
| */ |
| public void addChildBNF(String queryBNFId, String childQueryBNFId) { |
| registry.addChildBNF(queryBNFId, 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 |
| */ |
| public void addChildFactory(String queryBNFId, String childExpressionFactoryId) { |
| registry.addChildFactory(queryBNFId, 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) { |
| registry.addIdentifier(expressionFactoryId, 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) { |
| registry.addIdentifiers(expressionFactoryId, identifiers); |
| } |
| |
| /** |
| * Creates the base {@link JPQLGrammar} this one extends, if one exists. |
| * <p> |
| * <b>IMPORTANT:</b> The singleton instance of any {@link JPQLGrammar} (for example {@link |
| * JPQLGrammar1_0#instance() JPQLGrammar1_0.instance()} cannot be used, the API does not support |
| * extending it, a new instance has to be created. |
| * |
| * @return The base {@link JPQLGrammar} or <code>null</code> if there is no base grammar |
| */ |
| protected abstract JPQLGrammar buildBaseGrammar(); |
| |
| /** |
| * Creates a new {@link ExpressionRegistry} that will be used to store the definition of the JPQL |
| * grammar. This method is invoked if {@link #buildBaseGrammar()} returns <code>null</code>. |
| * |
| * @return The registry of {@link JPQLQueryBNF JPQLQueryBNFs}, {@link ExpressionFactory |
| * ExpressionFactories} and the JPQL identifiers |
| */ |
| protected ExpressionRegistry buildExpressionRegistry() { |
| return new ExpressionRegistry(); |
| } |
| |
| /** |
| * Creates the base {@link JPQLGrammar} this one extends. |
| * |
| * @return The base {@link JPQLGrammar} or <code>null</code> if this is the base grammar |
| */ |
| public JPQLGrammar getBaseGrammar() { |
| return jpqlGrammar; |
| } |
| |
| @Override |
| public ExpressionRegistry getExpressionRegistry() { |
| return registry; |
| } |
| |
| /** |
| * Initializes this JPQL grammar. |
| */ |
| protected void initialize() { |
| |
| // Create the base grammar, if this one is an extension |
| jpqlGrammar = buildBaseGrammar(); |
| |
| // There is no base grammar, create the local ExpressionRegistry |
| if (jpqlGrammar == null) { |
| registry = buildExpressionRegistry(); |
| } |
| // This grammar extends another grammar, simply use the base grammar's |
| // ExpressionRegistry so this grammar can modify it |
| else { |
| registry = jpqlGrammar.getExpressionRegistry(); |
| } |
| |
| // Add the support provided by this grammar |
| initializeIdentifiers(); |
| initializeBNFs(); |
| initializeExpressionFactories(); |
| } |
| |
| /** |
| * This method simply retrieves the {@link ExpressionRegistry} from the given {@link JPQLGrammar} |
| * and extend its grammar by calling the initialize methods from this one. |
| * |
| * @param jpqlGrammar The {@link JPQLGrammar} to extend with the content of this one without |
| * instantiating the base {@link JPQLGrammar} |
| */ |
| private void initialize(AbstractJPQLGrammar jpqlGrammar) { |
| |
| registry = jpqlGrammar.registry; |
| |
| // Add the support provided by this grammar |
| initializeIdentifiers(); |
| initializeBNFs(); |
| initializeExpressionFactories(); |
| } |
| |
| /** |
| * Registers the JPQL query BNFs defining the JPQL grammar. |
| */ |
| protected abstract void initializeBNFs(); |
| |
| /** |
| * Registers the {@link ExpressionFactory ExpressionFactories} required to properly parse JPQL |
| * queries. An {@link ExpressionFactory} is responsible to create an {@link Expression} object |
| * that represents a portion of the JPQL query. |
| */ |
| protected abstract void initializeExpressionFactories(); |
| |
| /** |
| * Registers the JPQL identifiers support by this {@link JPQLGrammar}. The registration |
| * involves registering the {@link JPAVersion} and the {@link IdentifierRole}. |
| */ |
| protected abstract void initializeIdentifiers(); |
| |
| /** |
| * Registers the given {@link JPQLQueryBNF}. The BNF will be registered using its unique |
| * identifier. |
| * |
| * @param queryBNF The {@link JPQLQueryBNF} to store |
| */ |
| protected void registerBNF(JPQLQueryBNF queryBNF) { |
| registry.registerBNF(queryBNF); |
| } |
| |
| /** |
| * Registers the given {@link ExpressionFactory} by storing it for all its identifiers. |
| * |
| * @param expressionFactory The {@link ExpressionFactory} to store |
| */ |
| protected void registerFactory(ExpressionFactory expressionFactory) { |
| registry.registerFactory(expressionFactory); |
| } |
| |
| /** |
| * 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 |
| */ |
| protected void registerIdentifierRole(String identifier, IdentifierRole role) { |
| registry.registerIdentifierRole(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 |
| */ |
| protected void registerIdentifierVersion(String identifier, JPAVersion version) { |
| registry.registerIdentifierVersion(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 |
| */ |
| public void setFallbackBNFId(String queryBNFId, String fallbackBNFId) { |
| registry.setFallbackBNFId(queryBNFId, fallbackBNFId); |
| } |
| |
| /** |
| * 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 |
| */ |
| public void setFallbackExpressionFactoryId(String queryBNFId, String fallbackExpressionFactoryId) { |
| registry.setFallbackExpressionFactoryId(queryBNFId, 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) { |
| registry.setHandleCollection(queryBNFId, 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) { |
| registry.setHandleNestedArray(queryBNFId, 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) { |
| registry.setHandleSubExpression(queryBNFId, handleSubExpression); |
| } |
| } |