HttpCacheEntry.java

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package com.apigee.sdk.apm.http.client.cache;

import java.io.Serializable;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;

import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.ProtocolVersion;
import org.apache.http.StatusLine;
import org.apache.http.message.HeaderGroup;

import com.apigee.sdk.apm.http.annotation.Immutable;

/**
 * Structure used to store an {@link HttpResponse} in a cache. Some entries can
 * optionally depend on system resources that may require explicit deallocation.
 * In such a case {@link #getResource()} should return a non-null instance of
 * {@link Resource} that must be deallocated by calling
 * {@link Resource#dispose()} method when no longer used.
 * 
 * @since 4.1
 */
@Immutable
public class HttpCacheEntry implements Serializable {

	private static final long serialVersionUID = -6300496422359477413L;

	private final Date requestDate;
	private final Date responseDate;
	private final StatusLine statusLine;
	private final HeaderGroup responseHeaders;
	private final Resource resource;
	private final Set<String> variantURIs;

	/**
	 * Create a new {@link HttpCacheEntry}
	 * 
	 * @param requestDate
	 *            Date/time when the request was made (Used for age
	 *            calculations)
	 * @param responseDate
	 *            Date/time that the response came back (Used for age
	 *            calculations)
	 * @param statusLine
	 *            HTTP status line
	 * @param responseHeaders
	 *            Header[] from original HTTP Response
	 */
	public HttpCacheEntry(final Date requestDate, final Date responseDate,
			final StatusLine statusLine, final Header[] responseHeaders,
			final Resource resource, final Set<String> variants) {
		super();
		if (requestDate == null) {
			throw new IllegalArgumentException("Request date may not be null");
		}
		if (responseDate == null) {
			throw new IllegalArgumentException("Response date may not be null");
		}
		if (statusLine == null) {
			throw new IllegalArgumentException("Status line may not be null");
		}
		if (responseHeaders == null) {
			throw new IllegalArgumentException(
					"Response headers may not be null");
		}
		if (resource == null) {
			throw new IllegalArgumentException("Resource may not be null");
		}
		this.requestDate = requestDate;
		this.responseDate = responseDate;
		this.statusLine = statusLine;
		this.responseHeaders = new HeaderGroup();
		this.responseHeaders.setHeaders(responseHeaders);
		this.resource = resource;
		this.variantURIs = variants != null ? new HashSet<String>(variants)
				: new HashSet<String>();
	}

	public StatusLine getStatusLine() {
		return this.statusLine;
	}

	public ProtocolVersion getProtocolVersion() {
		return this.statusLine.getProtocolVersion();
	}

	public String getReasonPhrase() {
		return this.statusLine.getReasonPhrase();
	}

	public int getStatusCode() {
		return this.statusLine.getStatusCode();
	}

	public Date getRequestDate() {
		return requestDate;
	}

	public Date getResponseDate() {
		return responseDate;
	}

	public Header[] getAllHeaders() {
		return responseHeaders.getAllHeaders();
	}

	public Header getFirstHeader(String name) {
		return responseHeaders.getFirstHeader(name);
	}

	public Header[] getHeaders(String name) {
		return responseHeaders.getHeaders(name);
	}

	public boolean hasVariants() {
		return getFirstHeader(HeaderConstants.VARY) != null;
	}

	public Set<String> getVariantURIs() {
		return Collections.unmodifiableSet(this.variantURIs);
	}

	public Resource getResource() {
		return this.resource;
	}

	@Override
	public String toString() {
		return "[request date=" + this.requestDate + "; response date="
				+ this.responseDate + "; statusLine=" + this.statusLine + "]";
	}

}