trunk/oak-search/src/main/java/org/apache/jackrabbit/oak/plugins/index/search/util/NodeStateCloner.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.jackrabbit.oak.plugins.index.search.util;

import org.apache.jackrabbit.oak.spi.state.ApplyDiff;
import org.apache.jackrabbit.oak.spi.state.NodeBuilder;
import org.apache.jackrabbit.oak.spi.state.NodeState;
import org.apache.jackrabbit.oak.spi.state.NodeStateUtils;

import static org.apache.jackrabbit.oak.plugins.memory.EmptyNodeState.EMPTY_NODE;

/**
 * A utility class that allows to clone a node structure, excluding hidden nodes.
 */
public class NodeStateCloner {

    private NodeStateCloner() {
        // a utility class
    }

    public static NodeState cloneVisibleState(NodeState state){
        NodeBuilder builder = EMPTY_NODE.builder();
        new ApplyVisibleDiff(builder).apply(state);
        return builder.getNodeState();
    }

    private static class ApplyVisibleDiff extends ApplyDiff {
        public ApplyVisibleDiff(NodeBuilder builder) {
            super(builder);
        }

        @Override
        public boolean childNodeAdded(String name, NodeState after) {
            if (NodeStateUtils.isHidden(name)){
                return true;
            }
            return after.compareAgainstBaseState(
                    EMPTY_NODE, new ApplyVisibleDiff(builder.child(name)));
        }
    }
}