gradle-master/subprojects/model-core/src/main/java/org/gradle/model/internal/core/EmptyModelProjection.java
/*
 * Copyright 2014 the original author or authors.
 *
 * 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
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.gradle.model.internal.core;

import com.google.common.base.Optional;
import org.gradle.model.internal.core.rule.describe.ModelRuleDescriptor;
import org.gradle.model.internal.type.ModelType;

import javax.annotation.Nullable;
import java.util.Collections;

public class EmptyModelProjection implements ModelProjection {

    public static final ModelProjection INSTANCE = new EmptyModelProjection();

    private EmptyModelProjection() {
    }

    @Nullable
    @Override
    public <T> ModelView<? extends T> asImmutable(ModelType<T> type, MutableModelNode node, @Nullable ModelRuleDescriptor ruleDescriptor) {
        return null;
    }

    @Nullable
    @Override
    public <T> ModelView<? extends T> asMutable(ModelType<T> type, MutableModelNode node, ModelRuleDescriptor ruleDescriptor) {
        return null;
    }

    @Override
    public <T> boolean canBeViewedAs(ModelType<T> type) {
        return false;
    }

    @Override
    public Iterable<String> getTypeDescriptions(MutableModelNode node) {
        return Collections.emptyList();
    }

    @Override
    public Optional<String> getValueDescription(MutableModelNode modelNodeInternal) {
        return Optional.absent();
    }

}
