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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.jdisc.application;
import com.google.common.collect.ImmutableList;
import java.net.URI;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* <p>This is an immutable set of ordered bindings from {@link UriPattern}s to some target type T. To create an instance
* of this class, you must 1) create a {@link BindingRepository}, 2) configure it using the {@link
* BindingRepository#bind(String, Object)} method, and finally 3) call {@link BindingRepository#activate()}.</p>
*
* @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen</a>
*/
public class BindingSet<T> implements Iterable<Map.Entry<UriPattern, T>> {
public static final String DEFAULT = "default";
private final Collection<Map.Entry<UriPattern, T>> bindings;
BindingSet(Collection<Map.Entry<UriPattern, T>> bindings) {
this.bindings = sort(bindings);
}
/**
* <p>Resolves the binding that best matches (see commentary on {@link BindingRepository#bind(String, Object)}) the
* given {@link URI}, and returns a {@link BindingMatch} object that describes the match and contains the
* matched target. If there is no binding that matches the given URI, this method returns null.</p>
*
* @param uri The URI to match against the bindings in this set.
* @return A {@link BindingMatch} object describing the match found, or null if not found.
*/
public BindingMatch<T> match(URI uri) {
for (Map.Entry<UriPattern, T> entry : bindings) {
UriPattern.Match match = entry.getKey().match(uri);
if (match != null) {
return new BindingMatch<>(match, entry.getValue());
}
}
return null;
}
/**
* <p>Resolves the binding that best matches (see commentary on {@link BindingRepository#bind(String, Object)}) the
* given {@link URI}, and returns that target. If there is no binding that matches the given URI, this method
* returns null.</p>
*
* <p>Apart from a <em>null</em>-guard, this is equal to <code>return match(uri).target()</code>.</p>
*
* @param uri The URI to match against the bindings in this set.
* @return The best matched target, or null.
* @see #match(URI)
*/
public T resolve(URI uri) {
BindingMatch<T> match = match(uri);
if (match == null) {
return null;
}
return match.target();
}
@Override
public Iterator<Map.Entry<UriPattern, T>> iterator() {
return bindings.iterator();
}
private static <T> Collection<Map.Entry<UriPattern, T>> sort(Collection<Map.Entry<UriPattern, T>> unsorted) {
List<Map.Entry<UriPattern, T>> ret = new LinkedList<>(unsorted);
Collections.sort(ret, new Comparator<Map.Entry<UriPattern, ?>>() {
@Override
public int compare(Map.Entry<UriPattern, ?> lhs, Map.Entry<UriPattern, ?> rhs) {
return lhs.getKey().compareTo(rhs.getKey());
}
});
return ImmutableList.copyOf(ret);
}
}
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