/**
* Copyright (C) cedarsoft GmbH.
*
* Licensed under the GNU General Public License version 3 (the "License")
* with Classpath Exception; you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.cedarsoft.org/gpl3ce
* (GPL 3 with Classpath Exception)
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3 only, as
* published by the Free Software Foundation. cedarsoft GmbH designates this
* particular file as subject to the "Classpath" exception as provided
* by cedarsoft GmbH in the LICENSE file that accompanied this code.
*
* This code 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
* version 3 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 3 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact cedarsoft GmbH, 72810 Gomaringen, Germany,
* or visit www.cedarsoft.com if you need additional information or
* have any questions.
*/
package com.cedarsoft.inject;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Module;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import java.lang.AssertionError;
import java.lang.Class;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
/**
* <p>GuiceModulesHelper class.</p>
*
* @author Johannes Schneider (<a href=mailto:js@cedarsoft.com>js@cedarsoft.com</a>)
*/
public class GuiceModulesHelper {
private GuiceModulesHelper() {
}
/**
* <p>minimize</p>
*
* @param modules a {@link List} object.
* @param testType a {@link Class} object.
* @return a {@link GuiceModulesHelper.Result} object.
*/
@NotNull
public static Result minimize( @NotNull List<? extends Module> modules, @NotNull Class<?> testType ) {
return minimize( modules, Key.get( testType ) );
}
/**
* <p>minimize</p>
*
* @param modules a {@link List} object.
* @param keys a {@link Key} object.
* @return a {@link GuiceModulesHelper.Result} object.
*/
@NotNull
public static Result minimize( @NotNull List<? extends Module> modules, @NotNull Key<?>... keys ) {
//Verify to ensure it works with all modules
verifyInjection( modules, keys );
return minimize( new Result( modules ), keys );
}
/**
* <p>minimize</p>
*
* @param result a {@link GuiceModulesHelper.Result} object.
* @param testType a {@link Class} object.
* @return a {@link GuiceModulesHelper.Result} object.
*/
@NotNull
public static Result minimize( @NotNull Result result, @NotNull Class<?> testType ) {
return minimize( result, Key.get( testType ) );
}
/**
* <p>minimize</p>
*
* @param result a {@link GuiceModulesHelper.Result} object.
* @param keys a {@link Key} object.
* @return a {@link GuiceModulesHelper.Result} object.
*/
public static Result minimize( @NotNull Result result, @NotNull Key<?>... keys ) {
//Iterate over all types (copy because the result is updated)
List<Module> modules = new ArrayList<Module>( result.getTypes() );
for ( Module current : modules ) {
try {
List<Module> copy = new ArrayList<Module>( modules );
copy.remove( current );
verifyInjection( copy, keys );
//Update the result
result.remove( current );
if ( copy.isEmpty() ) {
result.removeAll();
return result; //fast exit
}
//Try to minimize further
return minimize( result, keys );
} catch ( Exception ignore ) {
}
}
return result; //no minimization
}
private static void verifyInjection( @NotNull Iterable<? extends Module> modules, @NotNull Key<?>... keys ) {
Injector injector = Guice.createInjector( modules );
for ( Key<?> key : keys ) {
injector.getInstance( key );
}
}
/**
* <p>assertMinimizeNotPossible</p>
*
* @param modules a {@link List} object.
* @param testType a {@link Class} object.
* @throws AssertionError if any.
*/
public static void assertMinimizeNotPossible( @NotNull List<? extends Module> modules, @NotNull Class<?> testType ) throws AssertionError {
assertMinimizeNotPossible( modules, Key.get( testType ) );
}
/**
* <p>assertMinimizeNotPossible</p>
*
* @param modules a {@link List} object.
* @param keys a {@link Key} object.
* @throws AssertionError if any.
*/
public static void assertMinimizeNotPossible( @NotNull List<? extends Module> modules, @NotNull Key<?>... keys ) throws AssertionError {
GuiceModulesHelper.Result minimal = minimize( modules, keys );
if ( !minimal.getRemoved().isEmpty() ) {
throw new AssertionError( "Can be minimized:\nRemove:\n" + minimal.getRemovedClassNamesAsString() + minimal.asInstantiations() );
}
}
public static class Result {
@NotNull
private final List<? extends Module> types;
@NotNull
private final List<Module> removed = new ArrayList<Module>();
public Result( @NotNull List<? extends Module> types ) {
this.types = new ArrayList<Module>( types );
}
public int size() {
return types.size();
}
public void removeAll() {
removed.addAll( types );
types.clear();
}
public void remove( @NotNull Module toRemove ) {
types.remove( toRemove );
removed.add( toRemove );
}
@NotNull
public List<? extends Module> getTypes() {
return Collections.unmodifiableList( types );
}
@NotNull
public List<? extends Module> getRemoved() {
return Collections.unmodifiableList( removed );
}
@NotNull
@NonNls
public String getRemovedClassNamesAsString() {
StringBuilder builder = new StringBuilder();
for ( Module module : removed ) {
builder.append( "- " );
builder.append( module.getClass().getName() );
builder.append( "\n" );
}
return builder.toString();
}
@NotNull
@NonNls
public String asInstantiations() {
StringBuilder builder = new StringBuilder();
for ( Iterator<? extends Module> iterator = types.iterator(); iterator.hasNext(); ) {
Module module = iterator.next();
builder.append( "new " ).append( module.getClass().getName() ).append( "()" );
if ( iterator.hasNext() ) {
builder.append( ", " );
}
}
return builder.toString();
}
}
}