org.eclipse.sisu.space.QualifierCache Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2010-present Sonatype, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Stuart McCulloch (Sonatype, Inc.) - initial API and implementation
*******************************************************************************/
package org.eclipse.sisu.space;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.inject.Qualifier;
/**
* Caching {@link ClassVisitor} that maintains a map of known {@link Qualifier} annotations.
*/
final class QualifierCache
implements ClassVisitor
{
// ----------------------------------------------------------------------
// Constants
// ----------------------------------------------------------------------
private static final String QUALIFIER_DESC = "Ljavax/inject/Qualifier;";
private static final String NAMED_DESC = "Ljavax/inject/Named;";
// ----------------------------------------------------------------------
// Implementation fields
// ----------------------------------------------------------------------
private static final Map cachedResults = seedResults();
private boolean isQualified;
// ----------------------------------------------------------------------
// Public methods
// ----------------------------------------------------------------------
public void enterClass( final int modifiers, final String name, final String _extends, final String[] _implements )
{
// no-op
}
public AnnotationVisitor visitAnnotation( final String desc )
{
isQualified |= QUALIFIER_DESC.equals( desc );
return null;
}
public void leaveClass()
{
// no-op
}
// ----------------------------------------------------------------------
// Local methods
// ----------------------------------------------------------------------
/**
* Scans the given annotation type to see if it is marked with {@link Qualifier}.
*
* @param space The class space
* @param desc The annotation descriptor
* @return {@code true} if the annotation is a qualifier; otherwise {@code false}
*/
boolean qualify( final ClassSpace space, final String desc )
{
if ( NAMED_DESC.equals( desc ) )
{
return true;
}
final Boolean result = cachedResults.get( desc );
if ( null == result )
{
isQualified = false;
final String name = desc.substring( 1, desc.length() - 1 );
SpaceScanner.accept( this, space.getResource( name + ".class" ) );
cachedResults.put( desc, Boolean.valueOf( isQualified ) );
return isQualified;
}
return result.booleanValue();
}
/**
* Seeds the cache with the fully-qualified names listed in the 'sisu.qualifiers' system property.
*
* @return Seeded results
*/
private static Map seedResults()
{
final Map results = new ConcurrentHashMap( 32, 0.75f, 1 );
try
{
final String qualifiers = System.getProperty( "sisu.qualifiers" );
if ( qualifiers != null && qualifiers.length() > 0 )
{
final StringBuilder buf = new StringBuilder( "L" );
for ( final String q : Tokens.splitByComma( qualifiers ) )
{
buf.append( q.replace( '.', '/' ) ).append( ';' );
results.put( buf.toString(), Boolean.TRUE );
buf.setLength( 1 );
}
}
}
catch ( final RuntimeException e ) // NOPMD
{
// couldn't access system property, leave results unseeded
}
return results;
}
}