/*
 * Copyright (c) 2013, 2017 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.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.grizzly.http.util;

import static org.glassfish.grizzly.http.util.HttpCodecUtils.*;

This class serves as an HTTP header value holder, plus it implements useful
utility methods to optimize headers serialization.
Author:
Alexey Stashok/**
 * This class serves as an HTTP header value holder, plus it implements useful
 * utility methods to optimize headers serialization.
 * 
 * @author Alexey Stashok
 */
public final class HeaderValue {
    public static final HeaderValue IDENTITY = newHeaderValue("identity").prepare();
    
    private final String value;
    private byte[] preparedByteArray;
    
    
    
Creates a HeaderValue wrapper over a String header value representation. 
Params:
value – String header value representation
Returns:
a HeaderValue wrapper over a String heade value representation/**
     * Creates a {@link HeaderValue} wrapper over a {@link String}
     * header value representation.
     * 
     * @param value {@link String} header value representation
     * @return a {@link HeaderValue} wrapper over a {@link String}
     *         heade value representation
     */
    public static HeaderValue newHeaderValue(final String value) {
        return new HeaderValue(value);
    }

    private HeaderValue(final String value) {
        this.value = value;
    }
    
    
Prepare the HeaderValue for the serialization.
This method might be particularly useful if we use the same HeaderValue
over and over for different responses, so that the HeaderValue
will not have to be parsed and prepared for each response separately.
Returns:
this HeaderValue/**
     * Prepare the <tt>HeaderValue</tt> for the serialization.
     * 
     * This method might be particularly useful if we use the same <tt>HeaderValue</tt>
     * over and over for different responses, so that the <tt>HeaderValue</tt>
     * will not have to be parsed and prepared for each response separately.
     * 
     * @return this <tt>HeaderValue</tt>
     */
    public HeaderValue prepare() {
        if (preparedByteArray == null) {
            getByteArray();
        }
        
        return this;
    }

    
Returns:
true if header value is not null, or
        false otherwise/**
     * @return <tt>true</tt> if header value is not null, or
     *         <tt>false</tt> otherwise
     */
    public boolean isSet() {
        return value != null;
    }
    
    
Returns:
the header value string/**
     * @return the header value string
     */
    public String get() {
        return value;
    }
    
    
Returns:
the byte array representation of the header value/**
     * @return the byte array representation of the header value
     */
    public byte[] getByteArray() {
        // if there's prepared byte array - return it
        if (preparedByteArray != null) {
            return preparedByteArray;
        }
        
        if (value == null) {
            return EMPTY_ARRAY;
        }
        
        preparedByteArray = toCheckedByteArray(value);
        return preparedByteArray;
    }

    @Override
    public String toString() {
        return value;
    }

    
Serializes this HeaderValue value into a passed DataChunk. 
Params:
dc – DataChunk/**
     * Serializes this <tt>HeaderValue</tt> value into a passed {@link DataChunk}.
     * 
     * @param dc {@link DataChunk}
     */
    public void serializeToDataChunk(final DataChunk dc) {
        if (preparedByteArray != null) {
            dc.setBytes(preparedByteArray);
        } else {
            dc.setString(value);
        }
    }
}