com.google.gcloud.datastore.PartialKey.java Source code

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Here is the source code for com.google.gcloud.datastore.PartialKey.java

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/*
 * Copyright 2015 Google Inc. 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.gcloud.datastore;

import com.google.api.services.datastore.DatastoreV1;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.protobuf.InvalidProtocolBufferException;

import java.util.List;

/**
 * A partial key (without a name or id).
 * Could be used as metadata for {@link PartialEntity}.
 * This class is immutable.
 */
public class PartialKey extends BaseKey {

    private static final long serialVersionUID = -75301206578793347L;

    public static class Builder extends BaseKey.Builder<Builder> {

        private Builder(String dataset, String kind) {
            super(dataset, kind);
        }

        private Builder(PartialKey copyFrom) {
            super(copyFrom);
        }

        @Override
        public PartialKey build() {
            ImmutableList<PathElement> path = ImmutableList.<PathElement>builder().addAll(ancestors)
                    .add(PathElement.of(kind)).build();
            return new PartialKey(dataset, namespace, path);
        }
    }

    PartialKey(String dataset, String namespace, ImmutableList<PathElement> path) {
        super(dataset, namespace, path);
    }

    @Override
    protected Object fromPb(byte[] bytesPb) throws InvalidProtocolBufferException {
        return fromPb(DatastoreV1.Key.parseFrom(bytesPb));
    }

    static PartialKey fromPb(DatastoreV1.Key keyPb) {
        String dataset = null;
        String namespace = null;
        if (keyPb.hasPartitionId()) {
            DatastoreV1.PartitionId partitionIdPb = keyPb.getPartitionId();
            if (partitionIdPb.hasDatasetId()) {
                dataset = partitionIdPb.getDatasetId();
            }
            if (partitionIdPb.hasNamespace()) {
                namespace = partitionIdPb.getNamespace();
            }
        }
        List<DatastoreV1.Key.PathElement> pathElementsPb = keyPb.getPathElementList();
        Preconditions.checkArgument(!pathElementsPb.isEmpty(), "Path must not be empty");
        ImmutableList.Builder<PathElement> pathBuilder = ImmutableList.builder();
        for (DatastoreV1.Key.PathElement pathElementPb : pathElementsPb) {
            pathBuilder.add(PathElement.fromPb(pathElementPb));
        }
        ImmutableList<PathElement> path = pathBuilder.build();
        PathElement leaf = path.get(path.size() - 1);
        if (leaf.nameOrId() != null) {
            return new Key(dataset, namespace, path);
        }
        return new PartialKey(dataset, namespace, path);
    }

    public static Builder builder(String dataset, String kind) {
        return new Builder(dataset, kind);
    }

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

    public static Builder builder(Key parent, String kind) {
        return builder(parent.dataset(), kind).namespace(parent.namespace()).ancestors(parent.path());
    }
}