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A bundle containing code of all jar-based modules that provide
JAX-RS and Jersey-related features. Such a bundle is *only intended* for
developers that do not use Maven's dependency system.
The bundle does not include code for contributes, tests and samples.
/*
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://jersey.dev.java.net/CDDL+GPL.html
* or jersey/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at jersey/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
* [name of copyright owner]"
*
* Contributor(s):
*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.jersey.server.impl;
import com.sun.jersey.api.core.HttpRequestContext;
import com.sun.jersey.core.header.AcceptableLanguageTag;
import com.sun.jersey.core.header.AcceptableMediaType;
import com.sun.jersey.core.header.AcceptableToken;
import com.sun.jersey.core.header.QualityFactor;
import com.sun.jersey.server.impl.model.HttpHelper;
import java.util.Collection;
import java.util.List;
import java.util.Locale;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Variant;
/**
*
* @author [email protected]
*/
public final class VariantSelector {
private VariantSelector() { }
private static final class ListEntry {
private T t;
private ListEntry prev;
private ListEntry next;
public ListEntry() { }
public ListEntry(ListEntry prev, T t) {
this.t = t;
prev.next = this;
this.prev = prev;
}
public T value() {
return t;
}
public ListEntry next() {
return next;
}
public void removeTail() {
if (next != null) {
next.prev = null;
next = null;
}
}
public void remove() {
if (prev != null) {
prev.next = next;
}
if (next != null) {
next.prev = prev;
}
prev = next = null;
}
public void insertAfter(ListEntry e) {
if (this.next == e)
return;
e.remove();
e.prev = this;
e.next = this.next;
if (e.next != null)
e.next.prev = e;
this.next = e;
}
public static ListEntry create(Collection l) {
ListEntry head = new ListEntry();
ListEntry e = head;
for (T t: l) {
e = new ListEntry(e, t);
}
return head;
}
}
/**
* Interface to get a dimension value from a variant and check if an
* acceptable dimension value is compatable with a dimension value.
*
* @param T the acceptable dimension value type
* @param U the dimension value type
*/
private static interface DimensionChecker {
/**
* Get the dimension value from the variant
*
* @param v the variant
* @return the dimension value
*/
U getDimension(Variant v);
/**
* Ascertain if the acceptable dimension value is compatible with
* the dimension value
*
* @param t the acceptable dimension value
* @param u the dimension value
* @return true if the acceptable dimension value is compatible with
* the dimension value
*/
boolean isCompatible(T t, U u);
}
private static final DimensionChecker MEDIA_TYPE_DC =
new DimensionChecker() {
public MediaType getDimension(Variant v) {
return v.getMediaType();
}
public boolean isCompatible(AcceptableMediaType t, MediaType u) {
return t.isCompatible(u);
}
};
private static final DimensionChecker LANGUAGE_TAG_DC =
new DimensionChecker() {
public Locale getDimension(Variant v) {
return v.getLanguage();
}
public boolean isCompatible(AcceptableLanguageTag t, Locale u) {
return t.isCompatible(u);
}
};
private static final DimensionChecker CHARSET_DC =
new DimensionChecker() {
public String getDimension(Variant v) {
MediaType m = v.getMediaType();
return (m != null) ? m.getParameters().get("charset") : null;
}
public boolean isCompatible(AcceptableToken t, String u) {
return t.isCompatible(u);
}
};
private static final DimensionChecker ENCODING_DC =
new DimensionChecker() {
public String getDimension(Variant v) {
return v.getEncoding();
}
public boolean isCompatible(AcceptableToken t, String u) {
return t.isCompatible(u);
}
};
/**
* Select variants for a given dimension.
*
* @param head the head of the list of variants. The list will be modified
* so that it only contains variants that are the most acceptable.
* Hence any variants that are not acceptable or are less acceptable
* are removed from the list.
* @param as the list of acceptable dimension values, ordered by the quality
* parameter, with the highest quality dimension value occuring first.
* @param dc the dimension checker
*/
private static void selectVariants(ListEntry head,
List as, DimensionChecker dc) {
int q = QualityFactor.MINUMUM_QUALITY;
// Iterate over the acceptable entries
// This assumes the the entries are ordered by the quality
for (T a : as) {
// If entries of the higest quality factor have already been
// selected no need to continue further
if (a.getQuality() < q)
break;
// Iterate over the variants
ListEntry i = head.next();
while (i != null) {
final ListEntry i_next = i.next();
// Get the dimension value of the varient to check
final U d = dc.getDimension(i.value());
if (d != null) {
// Check if the acceptable entry is compatable with
// the dimension value
if (dc.isCompatible(a, d)) {
// Update the quality factor
// assert(q >= a.getQuality())
q = a.getQuality();
// Move the compatible varient entry to occur after
// the head
head.insertAfter(i);
// Set the head to the compatible varient entry
// This ensures that compatible entries are only
// checked once
head = i;
}
}
i = i_next;
}
}
// Order entries with null dimension values after those
// with acceptable dimension values
ListEntry i = head.next();
while (i != null) {
final ListEntry i_next = i.next();
if (dc.getDimension(i.value()) == null) {
head.insertAfter(i);
head = i;
}
i = i_next;
}
// Remove the unacceptable entries
// Any such entries will always occur after the head entry
head.removeTail();
}
public static Variant selectVariant(HttpRequestContext r, List variants) {
ListEntry vs = ListEntry.create(variants);
selectVariants(vs, HttpHelper.getAccept(r), MEDIA_TYPE_DC);
selectVariants(vs, HttpHelper.getAcceptLangauge(r), LANGUAGE_TAG_DC);
selectVariants(vs, HttpHelper.getAcceptCharset(r), CHARSET_DC);
selectVariants(vs, HttpHelper.getAcceptEncoding(r), ENCODING_DC);
return vs.next() != null ? vs.next().value() : null;
}
}
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