com.google.devtools.build.lib.testutil.FakeAttributeMapper.java Source code

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Here is the source code for com.google.devtools.build.lib.testutil.FakeAttributeMapper.java

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// Copyright 2017 The Bazel Authors. 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
//
// 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 com.google.devtools.build.lib.testutil;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;

import com.google.common.collect.ImmutableMap;
import com.google.devtools.build.lib.packages.AbstractAttributeMapper;
import com.google.devtools.build.lib.syntax.Type;
import java.util.List;
import java.util.Map;
import javax.annotation.Nullable;

/**
 * Faked implementation of {@link AbstractAttributeMapper} for use in testing.
 */
public class FakeAttributeMapper extends AbstractAttributeMapper {
    private final Map<String, FakeAttributeMapperEntry<?>> attrs;

    private FakeAttributeMapper(Map<String, FakeAttributeMapperEntry<?>> attrs) {
        super(null, null, null, null);
        this.attrs = ImmutableMap.copyOf(attrs);
    }

    @Override
    @Nullable
    public <T> T get(String attributeName, Type<T> type) {
        FakeAttributeMapperEntry<?> entry = attrs.get(attributeName);
        if (entry == null) {
            // Not specified in attributes or defaults
            assertWithMessage("Attribute " + attributeName + " not in attributes!").fail();
            return null;
        }

        return entry.validateAndGet(type);
    }

    @Override
    public boolean isAttributeValueExplicitlySpecified(String attributeName) {
        return attrs.containsKey(attributeName);
    }

    public static FakeAttributeMapper empty() {
        return builder().build();
    }

    public static Builder builder() {
        return new Builder();
    }

    /**
     * Builder to construct a {@link FakeAttributeMapper}. If no attributes are needed, use {@link
     * #empty()} instead.
     */
    public static class Builder {
        private final ImmutableMap.Builder<String, FakeAttributeMapperEntry<?>> mapBuilder = ImmutableMap.builder();

        private Builder() {
        }

        public Builder withStringList(String attribute, List<String> value) {
            mapBuilder.put(attribute, FakeAttributeMapperEntry.forStringList(value));
            return this;
        }

        public FakeAttributeMapper build() {
            return new FakeAttributeMapper(mapBuilder.build());
        }
    }

    private static class FakeAttributeMapperEntry<T> {
        private final Type<T> type;
        private final T value;

        private FakeAttributeMapperEntry(Type<T> type, T value) {
            this.type = type;
            this.value = value;
        }

        private static FakeAttributeMapperEntry<List<String>> forStringList(List<String> list) {
            return new FakeAttributeMapperEntry<>(Type.STRING_LIST, list);
        }

        private <U> U validateAndGet(Type<U> otherType) {
            assertThat(type).isSameAs(otherType);
            return otherType.cast(value);
        }
    }
}