SimpleStateObject.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 java.io.IOException;
import org.eclipse.persistence.jpa.jpql.ExpressionTools;

/**
 * This {@link StateObject} simply holds onto a string.
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
@SuppressWarnings("nls")
public abstract class SimpleStateObject extends AbstractStateObject {

    /**
     * The text held by this state object.
     */
    private String text;

    /**
     * Notifies the text property has changed.
     */
    public static final String TEXT_PROPERTY = "text";

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

    /**
     * Creates a new <code>SimpleStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param text The text held by this state object
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    protected SimpleStateObject(StateObject parent, String text) {
        super(parent);
        this.text = text;
    }

    /**
     * Returns the text held by this state object.
     *
     * @return This model's text value
     */
    public String getText() {
        return text;
    }

    /**
     * Determines whether this state object is holding a non-empty string.
     *
     * @return <code>true</code> if the text is non-empty; <code>false</code> otherwise
     */
    public boolean hasText() {
        return !ExpressionTools.stringIsEmpty(text);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isEquivalent(StateObject stateObject) {

        if (super.isEquivalent(stateObject)) {
            SimpleStateObject simple = (SimpleStateObject) stateObject;
            return ExpressionTools.valuesAreEqual(text, simple.text);
        }

        return false;
    }

    /**
     * Sets the text held by this state object.
     *
     * @param text This model's text value
     */
    public void setText(String text) {
        String oldText = this.text;
        this.text = text;
        firePropertyChanged(TEXT_PROPERTY, oldText, text);
    }

    /**
     * Sets the text to the given value without notifying the listeners.
     *
     * @param text This model's text value
     */
    protected void setTextInternally(String text) {
        this.text = text;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void toTextInternal(Appendable writer) throws IOException {
        if (text != null) {
            writer.append(text);
        }
    }
}