org.metawidget.inspector.impl.BaseTraitStyle Maven / Gradle / Ivy
// Metawidget (licensed under LGPL)
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package org.metawidget.inspector.impl;
import java.util.Collections;
import java.util.Map;
import java.util.regex.Pattern;
import org.metawidget.util.ArrayUtils;
import org.metawidget.util.CollectionUtils;
import org.metawidget.util.LogUtils;
import org.metawidget.util.LogUtils.Log;
/**
* Convenience implementation for ActionStyles and PropertyStyles.
*
* Handles caching and excluding names and types.
*
* @author Richard Kennard
*/
public abstract class BaseTraitStyle {
//
// Private members
//
/**
* Cache of trait lookups.
*
* Lookups are potentially expensive, so we cache them. The cache itself is a member variable,
* not a static, because we rely on BaseObjectInspector and
* ConfigReader to only create one instance of ActionStyle and
* PropertyStyle for all Inspectors.
*
* This also stops problems with subclasses of BaseTraitStyle sharing the same
* static cache.
*
* Note: the cache is unbounded, because the number of Classes in the system is fixed. This even
* applies to hot deployment products such as FakeReplace, because new Classes are replaced such
* that they .equal() their originals.
*/
/* package private */final Map> mCache;
private Pattern mExcludeBaseType;
private Class[] mExcludeReturnType;
private String[] mExcludeName;
//
// Protected members
//
protected final Log mLog = LogUtils.getLog( getClass() );
//
// Constructor
//
protected BaseTraitStyle( BaseTraitStyleConfig config ) {
if ( config.isCacheLookups() ) {
mCache = CollectionUtils.newHashMap();
} else {
mCache = null;
}
mExcludeBaseType = config.getExcludeBaseType();
mExcludeReturnType = config.getExcludeReturnType();
mExcludeName = config.getExcludeName();
}
//
// Public methods
//
/**
* SPI for tools such as FakeReplace that
* need to clear the cache.
*
* This does not affect immutability, as our external behaviour is unchanged (we will just be a
* little slower the next time we are called, while we re-cache).
*/
public void clearCache() {
if ( mCache == null ) {
return;
}
synchronized ( mCache ) {
mCache.clear();
}
}
//
// Protected methods
//
protected final Map getTraits( String type ) {
if ( mCache == null ) {
return getUncachedTraits( type );
}
synchronized ( mCache ) {
Map traits = getCachedTraits( type );
if ( traits == null ) {
traits = getUncachedTraits( type );
cacheTraits( type, traits );
}
return traits;
}
}
protected final Map getCachedTraits( String type ) {
return mCache.get( type );
}
protected final void cacheTraits( String type, Map traits ) {
mCache.put( type, Collections.unmodifiableMap( traits ) );
}
protected abstract Map getUncachedTraits( String type );
/**
* Whether to exclude the given trait, of the given type, in the given class, when searching
* for traits.
*
* This can be useful when the convention or base class define traits that are
* framework-specific, and should be filtered out from 'real' business model traits.
*
* By default, calls isExcludedReturnType and isExcludedName and
* returns true if either of them return true. Returns false otherwise.
*
* @return true if the trait should be excluded, false otherwise
*/
protected final boolean isExcluded( Class classToExclude, String name, Class returnType ) {
if ( isExcludedBaseType( classToExclude ) ) {
return true;
}
if ( isExcludedReturnType( returnType ) ) {
return true;
}
if ( isExcludedName( name ) ) {
return true;
}
return false;
}
/**
* Whether to exclude the given base type when searching up the model inheritance chain.
*
* This can be useful when the base types define traits that are framework-specific, and should
* be filtered out from 'real' business model traits.
*
* By default, excludes any base types from BaseTraitStyleConfig.setExcludeBaseType.
*
* @return true if the trait should be excluded, false otherwise
*/
protected boolean isExcludedBaseType( Class classToExclude ) {
String className = classToExclude.getName();
if ( mExcludeBaseType != null && mExcludeBaseType.matcher( className ).matches() ) {
return true;
}
return false;
}
/**
* Whether to exclude the given return type when searching for traits.
*
* This can be useful when the convention or base class define traits that are
* framework-specific, and should be filtered out from 'real' business model traits.
*
* By default, excludes any return types from
* BaseTraitStyleConfig.setExcludeReturnType.
*
* @param clazz
* return type to consider for exclusion
* @return true if the trait should be excluded, false otherwise
*/
protected boolean isExcludedReturnType( Class clazz ) {
if ( mExcludeReturnType != null ) {
for ( Class excludedClass : mExcludeReturnType ) {
if ( excludedClass.isAssignableFrom( clazz ) ) {
return true;
}
}
}
return false;
}
/**
* Whether to exclude the given name when searching for traits.
*
* This can be useful when the convention defines traits that are framework-specific (eg.
* getClass()), and should be filtered out from 'real' business model traits.
*
* By default, excludes any names from BaseTraitStyleConfig.setExcludeName.
*
* @param name
* to consider for exclusion
* @return true if the trait should be excluded, false otherwise
*/
protected boolean isExcludedName( String name ) {
if ( ArrayUtils.contains( mExcludeName, name ) ) {
return true;
}
return false;
}
}