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Core building blocks and API for the Metal library.
There is a newer version: 10.0.0
/*
 * Copyright 2013-2016 Netherlands Forensic Institute
 *
 * 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 io.parsingdata.metal.data.selection;

import static io.parsingdata.metal.Util.checkNotNull;

import io.parsingdata.metal.data.ImmutableList;
import io.parsingdata.metal.data.ParseGraph;
import io.parsingdata.metal.data.ParseItem;
import io.parsingdata.metal.data.ParseValue;
import io.parsingdata.metal.token.Token;

public final class ByToken {

    private ByToken() {}

    public static ParseItem get(final ParseGraph graph, final Token definition) {
        checkNotNull(graph, "graph");
        checkNotNull(definition, "definition");
        if (graph.definition == definition) { return graph; }
        if (graph.isEmpty()) { return null; }
        final ParseItem head = graph.head;
        if (head.isValue() && head.asValue().definition == definition) { return head; }
        if (head.isGraph()) {
            final ParseItem item = get(head.asGraph(), definition);
            if (item != null) { return item; }
        }
        return get(graph.tail, definition);
    }

    public static ImmutableList getAll(final ParseGraph graph, final Token definition) {
        checkNotNull(graph, "graph");
        checkNotNull(definition, "definition");
        return getAllRecursive(graph, definition);
    }

    private static ImmutableList getAllRecursive(final ParseGraph graph, final Token definition) {
        if (graph.isEmpty()) { return new ImmutableList<>(); }
        final ImmutableList tailResults = getAllRecursive(graph.tail, definition);
        final ImmutableList results = graph.definition == definition ? tailResults.add(graph) : tailResults;
        final ParseItem head = graph.head;
        if (head.isValue() && head.asValue().definition == definition) {
            return results.add(head);
        }
        if (head.isReference() && head.asReference().definition == definition) {
            return results.add(head);
        }
        if (head.isGraph()) {
            return results.add(getAllRecursive(head.asGraph(), definition));
        }
        return results;
    }

    public static ImmutableList getAllValues(final ParseGraph graph, final Token definition) {
        checkNotNull(graph, "graph");
        checkNotNull(definition, "definition");
        return getAllValuesRecursive(graph, definition);
    }

    private static ImmutableList getAllValuesRecursive(final ParseGraph graph, final Token definition) {
        if (graph.isEmpty()) { return new ImmutableList<>(); }
        final ImmutableList tailResults = getAllValuesRecursive(graph.tail, definition);
        final ParseItem head = graph.head;
        if (head.isValue() && head.asValue().definition == definition) {
            return tailResults.add(head.asValue());
        }
        if (head.isGraph()) {
            return tailResults.add(getAllValuesRecursive(head.asGraph(), definition));
        }
        return tailResults;
    }

    public static ImmutableList getAllRoots(final ParseGraph graph, final Token definition) {
        checkNotNull(graph, "graph");
        checkNotNull(definition, "definition");
        return getAllRootsRecursive(graph, null, definition);
    }

    private static ImmutableList getAllRootsRecursive(final ParseItem item, final ParseGraph parent, final Token definition) {
        final ImmutableList result = item.getDefinition() == definition && (parent == null || parent.getDefinition() != definition)
                ? ImmutableList.create(item)
                : new ImmutableList();
        if (item.isGraph() && !item.asGraph().isEmpty()) {
            return getAllRootsRecursive(item.asGraph().tail, item.asGraph(), definition)
                    .add(getAllRootsRecursive(item.asGraph().head, item.asGraph(), definition))
                    .add(result);
        }
        return result;
    }

}