com.google.inject.internal.UniqueAnnotations Maven / Gradle / Ivy
/*
* Copyright (C) 2008 Google Inc.
*
* Licensed 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.
*/
package com.google.inject.internal;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import com.google.inject.BindingAnnotation;
import java.lang.annotation.Annotation;
import java.lang.annotation.Retention;
import java.util.concurrent.atomic.AtomicInteger;
/** @author [email protected] (Jesse Wilson) */
public class UniqueAnnotations {
private UniqueAnnotations() {}
private static final AtomicInteger nextUniqueValue = new AtomicInteger(1);
/**
* Returns an annotation instance that is not equal to any other annotation instances, for use in
* creating distinct {@link com.google.inject.Key}s.
*/
public static Annotation create() {
return create(nextUniqueValue.getAndIncrement());
}
static Annotation create(final int value) {
return new Internal() {
@Override
public int value() {
return value;
}
@Override
public Class annotationType() {
return Internal.class;
}
@Override
public String toString() {
return "@" + Internal.class.getName() + "(value=" + value + ")";
}
@Override
public boolean equals(Object o) {
return o instanceof Internal && ((Internal) o).value() == value();
}
@Override
public int hashCode() {
return (127 * "value".hashCode()) ^ value;
}
};
}
@Retention(RUNTIME)
@BindingAnnotation
@interface Internal {
int value();
}
}