/*
 * Copyright 2021, TeamDev. All rights reserved.
 *
 * 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
 *
 * Redistribution and use in source and/or binary forms, with or without
 * modification, must retain the above copyright notice and the following
 * disclaimer.
 *
 * 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 FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package io.spine.tools.mc.java.protoc.method;

import com.google.common.collect.ImmutableList;
import io.spine.tools.mc.java.protoc.ClassMember;
import io.spine.tools.mc.java.protoc.CodeGenerationTask;
import io.spine.tools.mc.java.protoc.CompilerOutput;
import io.spine.tools.mc.java.protoc.ExternalClassLoader;
import io.spine.tools.protoc.MethodFactory;
import io.spine.tools.protoc.MethodFactoryName;
import io.spine.type.MessageType;
import org.checkerframework.checker.nullness.qual.NonNull;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.ImmutableList.toImmutableList;

/**
 * An abstract base for the method code generation tasks.
 */
abstract class MethodGenerationTask implements CodeGenerationTask {

    private final ExternalClassLoader<MethodFactory> classLoader;
    private final MethodFactoryName factoryName;

    MethodGenerationTask(ExternalClassLoader<MethodFactory> classLoader, MethodFactoryName factoryName) {
        this.classLoader = checkNotNull(classLoader);
        this.factoryName = checkNotNull(factoryName);
    }

    /**
     * Performs the actual method code generation using the supplied
     * {@linkplain #factoryName factory}.
     */
    ImmutableList<CompilerOutput> generateMethodsFor(@NonNull MessageType type) {
        MethodFactory factory = classLoader.newInstance(factoryName.getClassName().getCanonical());
        return factory
                .generateMethodsFor(type)
                .stream()
                .map(methodBody -> ClassMember.method(methodBody, type))
                .collect(toImmutableList());
    }
}

@@ -1870,16 +1870,81 @@
 bleList;
+%0Aimport static io.spine.util.Preconditions2.checkNotEmptyOrBlank;
 %0A%0A/**%0A *
@@ -2402,16 +2402,89 @@
 yName);%0A
+        checkNotEmptyOrBlank(factoryName.getClassName().getCanonical());%0A
     %7D%0A%0A 

Add a missing precondition