/*************************************************************************
* Copyright 2009-2012 Eucalyptus Systems, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*
* Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
* CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
* additional information or have any questions.
*
* This file may incorporate work covered under the following copyright
* and permission notice:
*
* Software License Agreement (BSD License)
*
* Copyright (c) 2008, Regents of the University of California
* All rights reserved.
*
* Redistribution and use of this software in source and binary forms,
* with or without modification, are permitted provided that the
* following conditions are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 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.
*
* 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
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* POSSIBILITY OF SUCH DAMAGE. USERS OF THIS SOFTWARE ACKNOWLEDGE
* THE POSSIBLE PRESENCE OF OTHER OPEN SOURCE LICENSED MATERIAL,
* COPYRIGHTED MATERIAL OR PATENTED MATERIAL IN THIS SOFTWARE,
* AND IF ANY SUCH MATERIAL IS DISCOVERED THE PARTY DISCOVERING
* IT MAY INFORM DR. RICH WOLSKI AT THE UNIVERSITY OF CALIFORNIA,
* SANTA BARBARA WHO WILL THEN ASCERTAIN THE MOST APPROPRIATE REMEDY,
* WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
* REPLACEMENT OF THE CODE SO IDENTIFIED, LICENSING OF THE CODE SO
* IDENTIFIED, OR WITHDRAWAL OF THE CODE CAPABILITY TO THE EXTENT
* NEEDED TO COMPLY WITH ANY SUCH LICENSES OR RIGHTS.
************************************************************************/
package com.eucalyptus.system;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.AnnotatedElement;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import com.eucalyptus.util.Classes;
import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Predicate;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Lists;
import javaslang.control.Option;
/**
* A builder-like utility for interrogating the {@link Annotation}s that may be present on instances
* of {@link AnnotatedElement}s.
* TODO:GRZE: wrong package: should be .util
*/
public class Ats implements Predicate<Class> {
private final List<AnnotatedElement> ancestry = Lists.newArrayList( );
private Ats( AnnotatedElement... ancestry ) {
for ( AnnotatedElement c : ancestry ) {
if ( c instanceof AnnotatedElement ) {
this.ancestry.add( c );
}
}
}
public <A extends Annotation> boolean has( Class<A> annotation ) {
for ( AnnotatedElement a : this.ancestry ) {
if ( a.isAnnotationPresent( annotation ) ) {
return true;
} else if ( a instanceof Class ) {
for ( Class<?> inter : ( ( Class<?> ) a ).getInterfaces( ) ) {
if ( inter.isAnnotationPresent( annotation ) ) {
return true;
}
}
}
}
return false;
}
public <A extends Annotation> A get( Class<A> annotation ) {
AnnotatedElement decl = find( annotation );
return decl == null
? null
: decl.getAnnotation( annotation );
}
public <A extends Annotation> Option<A> getOption( Class<A> annotation ) {
return Option.of( get( annotation ) );
}
/**
* Find the nearest conformant Class to the root of the Ats hierarcy that has the argument annotation.
* @param annotation
* @return Class which is annotated with {@link annotation} and is closest in terms of sub-typing to {@link #getRootClass()}
* @throws NoSuchElementException if no such class is found
*/
public <A extends Annotation,T> Class<T> findAncestor( final Class<A> annotation ) {
for ( final AnnotatedElement a : this.ancestry ) {
if ( a instanceof Class && a.isAnnotationPresent( annotation ) ) {
return ( Class<T> ) a;
}
}
throw new NoSuchElementException( "Failed to find ancestor with @" + annotation.getSimpleName( ) + " for root class " + getRootClass( ).getSimpleName( ) );
}
/**
* Find the nearest conformant AnnotatedElement to the root of the Ats hierarcy that has the argument annotation.
* @param annotation
* @return AnnotatedElement which is annotated with {@link annotation} and is closest in terms of sub-typing to {@link #getRootClass()}
* @throws NoSuchElementException if no such AnnotatedElement is found
*/
public <A extends Annotation> AnnotatedElement find( final Class<A> annotation ) {
for ( final AnnotatedElement a : this.ancestry ) {
if ( a.isAnnotationPresent( annotation ) ) {
return a;
} else if ( a instanceof Class ) {
for ( Class<?> inter : ( ( Class<?> ) a ).getInterfaces( ) ) {
if ( inter.isAnnotationPresent( annotation ) ) {
return inter;
}
}
}
}
return getRootClass( );
}
/**
* @return the root of this annotation hierarchy
*/
private Class getRootClass( ) {
AnnotatedElement a = this.ancestry.get( 0 );
return a instanceof Class ? ( Class ) a : null;
}
private static final LoadingCache<Object, Ats> atsCache = CacheBuilder.newBuilder().build(
new CacheLoader<Object, Ats>() {
@Override
public Ats load( Object input ) {
if ( input instanceof Class ) {
return new Ats( ( AnnotatedElement ) input );
} else if ( input instanceof AnnotatedElement ) {
return new Ats( ( AnnotatedElement ) input );
} else {
return new Ats( ( AnnotatedElement ) input.getClass( ) );
}
}
});
private static final LoadingCache<Object, Ats> atsHierarchyCache = CacheBuilder.newBuilder().build(
new CacheLoader<Object, Ats>() {
@Override
public Ats load( Object input ) {
if ( input instanceof AnnotatedElement ) {
return new Ats( Classes.ancestors( input ).toArray( new Class[] {} ) );
} else {
return new Ats( Classes.ancestors( input ).toArray( new Class[] {} ) );
}
}
});
public static Ats from( Object o ) {
if ( o instanceof AccessibleObject ) {
return atsCache.getUnchecked( o );
} else {
return atsCache.getUnchecked( Classes.typeOf( o ) );
}
}
public static Ats inClassHierarchy( Object o ) {
if ( o instanceof AccessibleObject ) {
return atsHierarchyCache.getUnchecked( o );
} else {
return atsHierarchyCache.getUnchecked( Classes.typeOf( o ) );
}
}
List<AnnotatedElement> getAncestry( ) {
return this.ancestry;
}
enum AnnotatedElementToString implements Function<AnnotatedElement, String> {
INSTANCE;
@Override
public String apply( AnnotatedElement input ) {
return input.toString( ) + ":" + "[" + Joiner.on( "," ).join( input.getAnnotations( ) ) + "]";
}
}
@Override
public String toString( ) {
return String.format( "Ats:class=%s\nAts:ancestor=%s", getRootClass( ),
Joiner.on( "Ats:ancestor=" ).join( Lists.transform( this.ancestry, AnnotatedElementToString.INSTANCE ) ) );
}
@Override
public boolean apply( Class input ) {
return this.has( input );
}
}