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/*
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*
* Copyright (c) 2012-2017 Oracle and/or its affiliates. All rights reserved.
*
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* 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
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*
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* file and include the License file at LICENSE.txt.
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package org.glassfish.jersey.message.internal;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
/**
* Quality parameter constants.
*
* @author Marek Potociar (marek.potociar at oracle.com)
*/
public final class Quality {
/**
* A "highest first" qualified element comparator.
*
* An element with higher quality value will be sorted ahead of elements with lower quality value.
*/
public static final Comparator QUALIFIED_COMPARATOR = new Comparator() {
@Override
public int compare(final Qualified o1, final Qualified o2) {
// reverse comparison to achieve the "higher first" behavior.
return Quality.compare(o2.getQuality(), o1.getQuality());
}
};
/**
* A "highest first" quality value comparator.
*
* A higher quality value will be sorted ahead of a lower quality value.
*/
public static final Comparator QUALITY_VALUE_COMPARATOR = new Comparator() {
@Override
public int compare(final Integer q1, final Integer q2) {
// reverse comparison to achieve the "higher first" behavior.
return Quality.compare(q2, q1);
}
};
/**
* Prevents instantiation.
*/
private Quality() {
throw new AssertionError("Instantiation not allowed.");
}
/**
* Quality HTTP header parameter name.
*/
public static final String QUALITY_PARAMETER_NAME = "q";
/**
* Quality source HTTP header parameter name.
*/
public static final String QUALITY_SOURCE_PARAMETER_NAME = "qs";
/**
* Minimum quality value.
*/
public static final int MINIMUM = 0;
/**
* Maximum quality value.
*/
public static final int MAXIMUM = 1000;
/**
* Default quality value.
*/
public static final int DEFAULT = MAXIMUM;
/**
* Add a quality parameter to a HTTP header parameter map (if needed).
*
* @param parameters a map of HTTP header parameters.
* @param qualityParamName name of the quality parameter ("q" or "qs").
* @param quality quality value in [ppm].
* @return parameter map containing the proper quality parameter if necessary.
*/
static Map enhanceWithQualityParameter(
final Map parameters, final String qualityParamName, final int quality) {
if (quality == DEFAULT) {
// special handling
if (parameters == null || parameters.isEmpty() || !parameters.containsKey(qualityParamName)) {
return parameters;
}
}
if (parameters == null || parameters.isEmpty()) {
return Collections.singletonMap(qualityParamName, qualityValueToString(quality));
}
try {
// Try to update the original map first...
parameters.put(qualityParamName, qualityValueToString(quality));
return parameters;
} catch (final UnsupportedOperationException uoe) {
// Unmodifiable map - let's create a new copy...
final Map result = new HashMap(parameters);
result.put(qualityParamName, qualityValueToString(quality));
return result;
}
}
/**
* Compares two {@code int} values numerically.
* The value returned is identical to what would be returned by:
*
* Integer.valueOf(x).compareTo(Integer.valueOf(y))
*
*
* Note: Taken from {@code Integer.compare()} from JDK 7.
*
* @param x the first {@code int} to compare
* @param y the second {@code int} to compare
* @return the value {@code 0} if {@code x == y};
* a value less than {@code 0} if {@code x < y}; and
* a value greater than {@code 0} if {@code x > y}
*/
private static int compare(final int x, final int y) {
return (x < y) ? -1 : ((x == y) ? 0 : 1);
}
private static String qualityValueToString(final float quality) {
final StringBuilder qsb = new StringBuilder(String.format(Locale.US, "%3.3f", (quality / 1000)));
int lastIndex;
while ((lastIndex = qsb.length() - 1) > 2 && qsb.charAt(lastIndex) == '0') {
qsb.deleteCharAt(lastIndex);
}
return qsb.toString();
}
}