gradle-master/subprojects/model-core/src/main/java/org/gradle/internal/properties/StaticValue.java
/*
 * Copyright 2017 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.internal.properties;

import org.gradle.api.Buildable;
import org.gradle.api.Task;
import org.gradle.api.internal.provider.HasConfigurableValueInternal;
import org.gradle.api.internal.provider.PropertyInternal;
import org.gradle.api.internal.tasks.TaskDependencyContainer;
import org.gradle.api.provider.HasConfigurableValue;
import org.gradle.internal.state.ModelObject;

import javax.annotation.Nullable;

/**
 * A {@link PropertyValue} backed by a fixed value.
 */
public class StaticValue implements PropertyValue {
    private final Object value;

    public StaticValue(@Nullable Object value) {
        this.value = value;
    }

    public static PropertyValue of(@Nullable Object value) {
        return new StaticValue(value);
    }

    @Override
    public TaskDependencyContainer getTaskDependencies() {
        if (value instanceof TaskDependencyContainer) {
            return (TaskDependencyContainer) value;
        }
        if (value instanceof Buildable) {
            return context -> context.add(value);
        }
        return TaskDependencyContainer.EMPTY;
    }

    public void attachProducer(Task producer) {
        if (value instanceof PropertyInternal) {
            ((PropertyInternal<?>) value).attachProducer((ModelObject) producer);
        }
    }

    @Override
    public void maybeFinalizeValue() {
        if (value instanceof HasConfigurableValue) {
            ((HasConfigurableValueInternal) value).implicitFinalizeValue();
        }
    }

    @Nullable
    @Override
    public Object call() {
        return value;
    }

    @Override
    public String toString() {
        return "Static: " + value;
    }
}
