jpa/org.eclipse.persistence.jpa.jpql/src/main/java/org/eclipse/persistence/jpa/jpql/tools/model/AbstractSelectExpressionStateObjectBuilder.java

/*
 * 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.tools.model;

import java.util.ArrayList;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.tools.model.query.ConstructorExpressionStateObject;
import org.eclipse.persistence.jpa.jpql.tools.model.query.ObjectExpressionStateObject;
import org.eclipse.persistence.jpa.jpql.tools.model.query.ResultVariableStateObject;
import org.eclipse.persistence.jpa.jpql.tools.model.query.SelectClauseStateObject;
import org.eclipse.persistence.jpa.jpql.tools.model.query.StateObject;

/**
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
public abstract class AbstractSelectExpressionStateObjectBuilder extends AbstractScalarExpressionStateObjectBuilder<ISelectExpressionStateObjectBuilder>
                                                                 implements ISelectExpressionStateObjectBuilder {

    /**
     * The list of select items, which were added by invoking {@link #append()}.
     */
    protected List<StateObject> stateObjectList;

    /**
     * Creates a new <code>AbstractSelectExpressionStateObjectBuilder</code>.
     *
     * @param parent The select clause for which this builder can create a select expression
     */
    protected AbstractSelectExpressionStateObjectBuilder(SelectClauseStateObject parent) {
        super(parent);
        stateObjectList = new ArrayList<StateObject>();
    }

    @Override
    public ISelectExpressionStateObjectBuilder append() {
        stateObjectList.add(pop());
        return this;
    }

    @Override
    public void commit() {
        if (hasStateObjects()) {
            append();
        }
        getParent().addItems(stateObjectList);
    }

    @Override
    protected SelectClauseStateObject getParent() {
        return (SelectClauseStateObject) super.getParent();
    }

    @Override
    public ISelectExpressionStateObjectBuilder new_(String className,
                                                    ISelectExpressionStateObjectBuilder... parameters) {

        checkBuilders(parameters);

        StateObject stateObject = new ConstructorExpressionStateObject(
            getParent(),
            className,
            stateObjects(parameters)
        );
        add(stateObject);
        return this;
    }

    @Override
    public ISelectExpressionStateObjectBuilder object(String identificationVariable) {
        StateObject stateObject = new ObjectExpressionStateObject(getParent(), identificationVariable);
        add(stateObject);
        return this;
    }

    @Override
    public ISelectExpressionStateObjectBuilder resultVariable(String resultVariable) {
        resultVariable(resultVariable, false);
        return this;
    }

    protected void resultVariable(String resultVariable, boolean as) {

        StateObject stateObject = new ResultVariableStateObject(
            getParent(),
            pop(),
            as,
            resultVariable
        );

        add(stateObject);
    }

    @Override
    public ISelectExpressionStateObjectBuilder resultVariableAs(String resultVariable) {
        resultVariable(resultVariable, true);
        return this;
    }

    @Override
    public ISelectExpressionStateObjectBuilder variable(String variable) {
        StateObject stateObject = buildIdentificationVariable(variable);
        add(stateObject);
        return this;
    }
}