InputParameterStateObject.java

/*******************************************************************************
 * Copyright (c) 2011, 2015 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 v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation
 *
 ******************************************************************************/
package org.eclipse.persistence.jpa.jpql.tools.model.query;

import org.eclipse.persistence.jpa.jpql.parser.InputParameter;

/**
 * Either positional or named parameters may be used. Positional and named parameters may not be
 * mixed in a single query. Input parameters can only be used in the <code><b>WHERE</b></code>
 * clause or <code><b>HAVING</b></code> clause of a query.
 *
 * @see InputParameter
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
public class InputParameterStateObject extends SimpleStateObject {

    /**
     * Creates a new <code>InputParameterStateObject</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 InputParameterStateObject(StateObject parent) {
        super(parent);
    }

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

    /**
     * {@inheritDoc}
     */
    public void accept(StateObjectVisitor visitor) {
        visitor.visit(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public InputParameter getExpression() {
        return (InputParameter) super.getExpression();
    }

    /**
     * Determines whether this parameter is a positional parameter, i.e. the parameter type is '?'.
     *
     * @return <code>true</code> if the parameter type is '?'; <code>false</code> if it's ':'
     */
    public boolean isNamed() {
        if (hasText()) {
            return getText().charAt(0) == InputParameter.NAMED_PARAMETER.charAt(0);
        }
        return false;
    }

    /**
     * Determines whether this parameter is a positional parameter, i.e. the parameter type is ':'.
     *
     * @return <code>true</code> if the parameter type is ':'; <code>false</code> if it's '?'
     */
    public boolean isPositional() {
        if (hasText()) {
            return getText().charAt(0) == InputParameter.POSITIONAL_PARAMETER.charAt(0);
        }
        return false;
    }

    /**
     * Keeps a reference of the {@link InputParameter 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 InputParameter parsed object} representing an input parameter
     */
    public void setExpression(InputParameter expression) {
        super.setExpression(expression);
    }
}