| /* |
| * Copyright (c) 2012, 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.Assert; |
| import org.eclipse.persistence.jpa.jpql.ExpressionTools; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * This {@link FunctionExpressionFactory} creates a new {@link FunctionExpression} when the portion |
| * of the query to parse starts with an identifier related to a SQL function. |
| * |
| * @see FunctionExpression |
| * |
| * @version 2.5 |
| * @since 2.4 |
| * @author James |
| */ |
| @SuppressWarnings("nls") |
| public final class FunctionExpressionFactory extends ExpressionFactory { |
| |
| /** |
| * The number of {@link ParameterCount parameters} a {@link FunctionExpression} can have. |
| */ |
| private ParameterCount parameterCount; |
| |
| /** |
| * The unique identifier of the {@link JPQLQueryBNF} that will be used to parse the arguments of |
| * the function expression. |
| */ |
| private String parameterQueryBNFId; |
| |
| /** |
| * The unique identifier for this {@link FunctionExpressionFactory}. |
| */ |
| public static final String ID = Expression.FUNCTION; |
| |
| /** |
| * Creates a new <code>FunctionExpressionFactory</code>. |
| * |
| * @param id The unique identifier of this factory |
| * @param parameterCount The number of {@link ParameterCount parameters} a {@link |
| * FunctionExpression} can have |
| * @param parameterQueryBNFId The unique identifier of the {@link JPQLQueryBNF} that will be used |
| * to parse the arguments of the function expression |
| * @param identifiers The JPQL identifiers handled by this factory |
| */ |
| public FunctionExpressionFactory(String id, |
| ParameterCount parameterCount, |
| String parameterQueryBNFId, |
| String... identifiers) { |
| |
| super(id, identifiers); |
| setParameterCount(parameterCount); |
| setParameterQueryBNFId(parameterQueryBNFId); |
| } |
| |
| /** |
| * Creates a new <code>FunctionExpressionFactory</code>. |
| * |
| * @param id The unique identifier of this factory |
| * @param identifiers The JPQL identifiers handled by this factory |
| */ |
| public FunctionExpressionFactory(String id, String... identifiers) { |
| this(id, ParameterCount.ZERO_OR_MANY, FunctionItemBNF.ID, identifiers); |
| } |
| |
| @Override |
| protected AbstractExpression buildExpression(AbstractExpression parent, |
| WordParser wordParser, |
| String word, |
| JPQLQueryBNF queryBNF, |
| AbstractExpression expression, |
| boolean tolerant) { |
| |
| // Search for the constant that is registered with this factory |
| String identifier = null; |
| |
| for (String possibleIdentifier : identifiers()) { |
| if (possibleIdentifier.equalsIgnoreCase(word)) { |
| identifier = possibleIdentifier; |
| break; |
| } |
| } |
| |
| // No constant was found |
| if (identifier == null) { |
| return null; |
| } |
| |
| // Make sure the new function is a real expression and not a variable name. |
| // Example: SELECT column FROM Column column |
| if (ExpressionTools.isFunctionExpression(wordParser, identifier)) { |
| expression = new FunctionExpression(parent, identifier, parameterCount, parameterQueryBNFId); |
| expression.parse(wordParser, tolerant); |
| return expression; |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Sets the number of parameters a {@link FunctionExpression} can have, which will be during |
| * validation. |
| * |
| * @param parameterCount The number of parameters |
| */ |
| public void setParameterCount(ParameterCount parameterCount) { |
| Assert.isNotNull(parameterCount, "The ParameterCount cannot be null"); |
| this.parameterCount = parameterCount; |
| } |
| |
| /** |
| * Sets the BNF that will be used when parsing the function's arguments. |
| * |
| * @param parameterQueryBNFId The unique identifier of the {@link JPQLQueryBNF} that will be used |
| * to parse the arguments of the function expression |
| */ |
| public void setParameterQueryBNFId(String parameterQueryBNFId) { |
| Assert.isNotNull(parameterQueryBNFId, "The JPQLQueryBNF for the parameters cannot be null"); |
| this.parameterQueryBNFId = parameterQueryBNFId; |
| } |
| |
| /** |
| * The number of parameters a {@link FunctionExpression} can have. |
| */ |
| public enum ParameterCount { |
| |
| /** |
| * Only one parameter is allowed. |
| */ |
| ONE, |
| |
| /** |
| * [1, n] are allowed. |
| */ |
| ONE_OR_MANY, |
| |
| /** |
| * No parameters are allowed. |
| */ |
| ZERO, |
| |
| /** |
| * [0, n] are allowed. |
| */ |
| ZERO_OR_MANY, |
| |
| /** |
| * [0, 1] are allowed. |
| */ |
| ZERO_OR_ONE |
| } |
| } |