jpa/org.eclipse.persistence.jpa.jpql/src/main/java/org/eclipse/persistence/jpa/jpql/tools/model/query/NotExpressionStateObject.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.query;

import java.io.IOException;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.parser.ConditionalPrimaryBNF;
import org.eclipse.persistence.jpa.jpql.parser.NotExpression;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;

/**
 * <div><p><b>BNF:</b> <code>expression ::= NOT conditional_primary</code></p></div>
 *
 * @see NotExpression
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public class NotExpressionStateObject extends AbstractStateObject {

    /**
     * The {@link StateObject} representing the negated expression.
     */
    private StateObject stateObject;

    /**
     * Notifies the state object property has changed.
     */
    public static final String STATE_OBJECT_PROPERTY = "stateObject";

    /**
     * Creates a new <code>NotExpressionStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public NotExpressionStateObject(StateObject parent) {
        super(parent);
    }

    /**
     * Creates a new <code>NotExpressionStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param stateObject The {@link StateObject} representing the negated expression
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public NotExpressionStateObject(StateObject parent, StateObject stateObject) {
        super(parent);
        this.stateObject = parent(stateObject);
    }

    /**
     * Creates a new <code>NotExpressionStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param jpqlFragment The portion of the JPQL query that follows <code><b>NOT</b></code>, which
     * will be parsed and converted into a {@link StateObject}
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public NotExpressionStateObject(StateObject parent, String jpqlFragment) {
        super(parent);
        parse(jpqlFragment);
    }

    @Override
    public void accept(StateObjectVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    protected void addChildren(List<StateObject> children) {
        super.addChildren(children);
        if (stateObject != null) {
            children.add(stateObject);
        }
    }

    @Override
    public NotExpression getExpression() {
        return (NotExpression) super.getExpression();
    }

    /**
     * Returns the {@link StateObject} representing the negated expression.
     *
     * @return The {@link StateObject} representing the negated expression
     */
    public StateObject getStateObject() {
        return stateObject;
    }

    /**
     * Determines whether the {@link StateObject} representing the encapsulated expression is
     * present or not.
     *
     * @return <code>true</code> if the encapsulated {@link StateObject} is not <code>null</code>;
     * <code>false</code> otherwise
     */
    public boolean hasStateObject() {
        return stateObject != null;
    }

    @Override
    public boolean isEquivalent(StateObject stateObject) {

        if (super.isEquivalent(stateObject)) {
            NotExpressionStateObject not = (NotExpressionStateObject) stateObject;
            return areEquivalent(stateObject, not.stateObject);
        }

        return false;
    }

    /**
     * Parses the given JPQL fragment, which represents the negated expression, and creates the
     * {@link StateObject}.
     *
     * @param jpqlFragment The portion of the query representing the negated expression
     */
    public void parse(String jpqlFragment) {
        StateObject stateObject = buildStateObject(jpqlFragment, ConditionalPrimaryBNF.ID);
        setStateObject(stateObject);
    }

    /**
     * Keeps a reference of the {@link NotExpression parsed object} object, which should only be
     * done when this object is instantiated during the conversion of a parsed JPQL query into
     * {@link StateObject StateObjects}.
     *
     * @param expression The {@link NotExpression parsed object} representing a <code><b>NOT</b></code>
     * expression
     */
    public void setExpression(NotExpression expression) {
        super.setExpression(expression);
    }

    /**
     * Sets the given {@link StateObject} as the new negated expression.
     *
     * @param stateObject The {@link StateObject} representing the negated expression
     */
    public void setStateObject(StateObject stateObject) {
        StateObject oldStateObject = this.stateObject;
        this.stateObject = parent(stateObject);
        firePropertyChanged(STATE_OBJECT_PROPERTY, oldStateObject, stateObject);
    }

    @Override
    protected void toTextInternal(Appendable writer) throws IOException {
        writer.append(NOT);
        if (stateObject != null) {
            writer.append(SPACE);
            stateObject.toString(writer);
        }
    }
}