com.jcabi.http.response.WebLinkingResponse Maven / Gradle / Ivy
/**
* Copyright (c) 2011-2014, jcabi.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met: 1) Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer. 2) Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution. 3) Neither the name of the jcabi.com nor
* the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.jcabi.http.response;
import com.jcabi.aspects.Immutable;
import com.jcabi.http.Request;
import com.jcabi.http.Response;
import com.jcabi.immutable.ArrayMap;
import java.io.IOException;
import java.net.URI;
import java.util.Collection;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.validation.constraints.NotNull;
import lombok.EqualsAndHashCode;
/**
* Web Linking response.
*
* This response decorator is able to understand and parse {@code Link}
* HTTP header according to
* RFC 5988 "Web Linking",
* for example:
*
*
String name = new JdkRequest("http://my.example.com")
* .fetch()
* .as(WebLinkingResponse.class)
* .follow("next")
* .fetch();
*
* The class is immutable and thread-safe.
*
* @author Yegor Bugayenko ([email protected])
* @version $Id$
* @since 0.9
* @see RFC 5988 "Web Linking"
*/
@Immutable
@EqualsAndHashCode(callSuper = true)
@SuppressWarnings("PMD.TooManyMethods")
public final class WebLinkingResponse extends AbstractResponse {
/**
* ImmutableHeader name.
*/
private static final String HEADER = "Link";
/**
* Param name.
*/
private static final String REL = "rel";
/**
* Public ctor.
* @param resp Response
*/
public WebLinkingResponse(
@NotNull(message = "response can't be NULL") final Response resp) {
super(resp);
}
/**
* Follow link by REL.
* @param rel Relation name
* @return The same object
* @throws IOException If fails
*/
@NotNull(message = "response is never NULL")
public Request follow(@NotNull(message = "rel can't be NULL")
final String rel) throws IOException {
final WebLinkingResponse.Link link = this.links().get(rel);
if (link == null) {
throw new IOException(
String.format(
"Link with rel=\"%s\" doesn't exist, use #hasLink()",
rel
)
);
}
return new RestResponse(this).jump(link.uri());
}
/**
* Get all links provided.
* @return List of all links found
* @throws IOException If fails
*/
@NotNull(message = "list of links is never NULL")
@SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
public Map links() throws IOException {
final ConcurrentMap links =
new ConcurrentHashMap();
final Collection headers =
this.headers().get(WebLinkingResponse.HEADER);
if (headers != null) {
for (final String header : headers) {
for (final String part : header.split(",")) {
final WebLinkingResponse.Link link =
new WebLinkingResponse.SimpleLink(part.trim());
final String rel = link.get(WebLinkingResponse.REL);
if (rel != null) {
links.put(rel, link);
}
}
}
}
return links;
}
/**
* Single link.
*/
@Immutable
public interface Link extends Map {
/**
* Its URI.
* @return URI
*/
URI uri();
}
/**
* Implementation of a link.
*/
@Immutable
@EqualsAndHashCode
private static final class SimpleLink implements WebLinkingResponse.Link {
/**
* Pattern to match link value.
*/
@SuppressWarnings("PMD.UnusedPrivateField")
private static final Pattern PTN = Pattern.compile(
"<([^>]+)>\\s*;(.*)"
);
/**
* URI encapsulated.
*/
private final transient String addr;
/**
* Map of link params.
*/
private final transient ArrayMap params;
/**
* Public ctor (parser).
* @param text Text to parse
* @throws IOException If fails
*/
SimpleLink(final String text) throws IOException {
final Matcher matcher = WebLinkingResponse.SimpleLink.PTN
.matcher(text);
if (!matcher.matches()) {
throw new IOException(
String.format(
"Link header value doesn't comply to RFC-5988: \"%s\"",
text
)
);
}
this.addr = matcher.group(1);
final ConcurrentMap args =
new ConcurrentHashMap();
for (final String pair
: matcher.group(2).trim().split("\\s*;\\s*")) {
final String[] parts = pair.split("=");
args.put(
parts[0].trim().toLowerCase(Locale.ENGLISH),
parts[1].trim().replaceAll("(^\"|\"$)", "")
);
}
this.params = new ArrayMap(args);
}
@Override
public URI uri() {
return URI.create(this.addr);
}
@Override
public int size() {
return this.params.size();
}
@Override
public boolean isEmpty() {
return this.params.isEmpty();
}
@Override
public boolean containsKey(final Object key) {
return this.params.containsKey(key);
}
@Override
public boolean containsValue(final Object value) {
return this.params.containsValue(value);
}
@Override
public String get(final Object key) {
return this.params.get(key);
}
@Override
public String put(final String key, final String value) {
throw new UnsupportedOperationException("#put()");
}
@Override
public String remove(final Object key) {
throw new UnsupportedOperationException("#remove()");
}
@Override
public void putAll(final Map map) {
throw new UnsupportedOperationException("#putAll()");
}
@Override
public void clear() {
throw new UnsupportedOperationException("#clear()");
}
@Override
public Set keySet() {
return this.params.keySet();
}
@Override
public Collection values() {
return this.params.values();
}
@Override
public Set> entrySet() {
return this.params.entrySet();
}
}
}