ValueObjectImpl.java

/*
 * Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */
package com.sun.beans.decoder;

/**
 * This utility class provides {@code static} method
 * to create the object that contains the result of method execution.
 *
 * @since 1.7
 *
 * @author Sergey A. Malenkov
 */
final class ValueObjectImpl implements ValueObject {
    static final ValueObject NULL = new ValueObjectImpl(null);
    static final ValueObject VOID = new ValueObjectImpl();

    /**
     * Returns the object that describes returning value.
     *
     * @param value  the result of method execution
     * @return the object that describes value
     */
    static ValueObject create(Object value) {
        return (value != null)
                ? new ValueObjectImpl(value)
                : NULL;
    }

    private Object value;
    private boolean isVoid;

    /**
     * Creates the object that describes returning void value.
     */
    private ValueObjectImpl() {
        this.isVoid = true;
    }

    /**
     * Creates the object that describes returning non-void value.
     *
     * @param value  the result of method execution
     */
    private ValueObjectImpl(Object value) {
        this.value = value;
    }

    /**
     * Returns the result of method execution.
     *
     * @return the result of method execution
     */
    public Object getValue() {
        return this.value;
    }

    /**
     * Returns {@code void} state of this value object.
     *
     * @return {@code true} if value should be ignored,
     *         {@code false} otherwise
     */
    public boolean isVoid() {
        return this.isVoid;
    }
}