org.glassfish.grizzly.http.util.HeaderValue Maven / Gradle / Ivy

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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
 */
public final class HeaderValue {
    public static final HeaderValue IDENTITY = newHeaderValue("identity").prepare();
    
    private final String value;
    private byte[] preparedByteArray;
    
    
    /**
     * 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.
     * 
     * @return this HeaderValue
     */
    public HeaderValue prepare() {
        if (preparedByteArray == null) {
            getByteArray();
        }
        
        return this;
    }

    /**
     * @return true if header value is not null, or
     *         false otherwise
     */
    public boolean isSet() {
        return value != null;
    }
    
    /**
     * @return the header value string
     */
    public String get() {
        return 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 {@link DataChunk}.
     * 
     * @param dc {@link DataChunk}
     */
    public void serializeToDataChunk(final DataChunk dc) {
        if (preparedByteArray != null) {
            dc.setBytes(preparedByteArray);
        } else {
            dc.setString(value);
        }
    }
}