org.eclipse.persistence.jpa.jpql.JPQLQueryDeclaration Maven / Gradle / Ivy
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/*
* Copyright (c) 2012, 2020 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;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.parser.Expression;
import org.eclipse.persistence.jpa.jpql.parser.Join;
/**
* A JPQLQueryDeclaration represents either an identification variable declaration or a
* collection member declaration. For a subquery, the declaration can be a derived path expression.
*
* 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.
*
* @version 2.5
* @since 2.4
* @author Pascal Filion
*/
public interface JPQLQueryDeclaration {
/**
* Returns the range variable declaration if this is a range declaration otherwise the
* collection-valued path expression when this is a collection member declaration.
*
* @return Either the range variable declaration or the collection-valued path expression
*/
Expression getBaseExpression();
/**
* Returns the declaration expression, which is either an {@link
* org.eclipse.persistence.jpa.jpql.parser.IdentificationVariableDeclaration IdentificationVariableDeclaration}
* or a {@link org.eclipse.persistence.jpa.jpql.parser.CollectionMemberDeclaration CollectionMemberDeclaration}
* when part of a FROM clause, otherwise it's either the {@link
* org.eclipse.persistence.jpa.jpql.parser.DeleteClause DeleteClause} or the {@link
* org.eclipse.persistence.jpa.jpql.parser.UpdateClause UpdateClause}.
*
* @return The root of the declaration expression
*/
Expression getDeclarationExpression();
/**
* Returns the JOIN expressions defined with this declaration, if supported.
* The list contains the JOIN expressions in ordered they were declared.
*
* @return The JOIN expressions defined with this declaration or an empty list if this
* declaration does not support it
*/
List getJoins();
/**
* Determines the type this declaration represents.
*
* @return One of the possible types
*/
Type getType();
/**
* Returns the identification variable name that is defining either the abstract schema name
* or the collection-valued path expression
*
* @return The identification variable or an empty string if none was defined
*/
String getVariableName();
/**
* Determines whether the declaration contains JOIN expressions. This can be
* true only when {@link Type#isRange()} returns true. A collection
* member declaration does not have JOIN expressions.
*
* @return true if at least one JOIN expression was parsed;
* otherwise false
*/
boolean hasJoins();
/**
* This enum type defines the various types of declarations supported by both the JPA functional
* specification and EclipseLink.
*/
public enum Type {
/**
* Indicates the "root" object maps a fully qualified class name.
*/
CLASS_NAME(false),
/**
* Indicates the "root" object maps a collection-valued path expression.
*/
COLLECTION(false),
/**
* Indicates the "root" object is a derived path expression where the identification variable
* is declared in the super query, otherwise it's an entity name.
*/
DERIVED(true),
/**
* Indicates the "root" object maps to an entity.
*/
RANGE(true),
/**
* Indicates the "root" object maps to a subquery.
*/
SUBQUERY(false),
/**
* Indicates the "root" object maps directly to a database table.
*/
TABLE(false),
/**
* Indicates the "root" object maps to an unknown expression.
*/
UNKNOWN(false);
/**
* Flag used to determine if the type represents a range variable declaration.
*/
private boolean range;
private Type(boolean range) {
this.range = range;
}
/**
* Determines whether this type represents a range variable declaration.
*
* @return true if this constant represents a range variable declaration;
* false otherwise
*/
public boolean isRange() {
return range;
}
}
}