Example usage for org.apache.http.client.cache HeaderConstants AGE

Introduction

In this page you can find the example usage for org.apache.http.client.cache HeaderConstants AGE.

Prototype

String AGE

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Usage

From source file:org.apache.http.impl.client.cache.ResponseCachingPolicy.java

/**
 * Determines if an HttpResponse can be cached.
 *
 * @param httpMethod What type of request was this, a GET, PUT, other?
 * @param response The origin response//from w ww. ja  v  a 2  s . c  o m
 * @return <code>true</code> if response is cacheable
 */
public boolean isResponseCacheable(String httpMethod, HttpResponse response) {
    boolean cacheable = false;

    if (!HeaderConstants.GET_METHOD.equals(httpMethod)) {
        log.debug("Response was not cacheable.");
        return false;
    }

    switch (response.getStatusLine().getStatusCode()) {
    case HttpStatus.SC_OK:
    case HttpStatus.SC_NON_AUTHORITATIVE_INFORMATION:
    case HttpStatus.SC_MULTIPLE_CHOICES:
    case HttpStatus.SC_MOVED_PERMANENTLY:
    case HttpStatus.SC_GONE:
        // these response codes MAY be cached
        cacheable = true;
        log.debug("Response was cacheable");
        break;
    case HttpStatus.SC_PARTIAL_CONTENT:
        // we don't implement Range requests and hence are not
        // allowed to cache partial content
        log.debug("Response was not cacheable (Partial Content)");
        return cacheable;

    default:
        // If the status code is not one of the recognized
        // available codes in HttpStatus Don't Cache
        log.debug("Response was not cacheable (Unknown Status code)");
        return cacheable;
    }

    Header contentLength = response.getFirstHeader(HTTP.CONTENT_LEN);
    if (contentLength != null) {
        int contentLengthValue = Integer.parseInt(contentLength.getValue());
        if (contentLengthValue > this.maxObjectSizeBytes)
            return false;
    }

    Header[] ageHeaders = response.getHeaders(HeaderConstants.AGE);

    if (ageHeaders.length > 1)
        return false;

    Header[] expiresHeaders = response.getHeaders(HeaderConstants.EXPIRES);

    if (expiresHeaders.length > 1)
        return false;

    Header[] dateHeaders = response.getHeaders(HTTP.DATE_HEADER);

    if (dateHeaders.length != 1)
        return false;

    try {
        DateUtils.parseDate(dateHeaders[0].getValue());
    } catch (DateParseException dpe) {
        return false;
    }

    for (Header varyHdr : response.getHeaders(HeaderConstants.VARY)) {
        for (HeaderElement elem : varyHdr.getElements()) {
            if ("*".equals(elem.getName())) {
                return false;
            }
        }
    }

    if (isExplicitlyNonCacheable(response))
        return false;

    return (cacheable || isExplicitlyCacheable(response));
}

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