com.twosigma.webtau.http.datanode.NullDataNode Maven / Gradle / Ivy

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/*
 * Copyright 2019 TWO SIGMA OPEN SOURCE, LLC
 *
 * 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.twosigma.webtau.http.datanode;

import com.twosigma.webtau.data.traceable.TraceableValue;

import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class NullDataNode implements DataNode {
    private final DataNodeId id;

    public NullDataNode(DataNodeId id) {
        this.id = id;
    }

    @Override
    public DataNodeId id() {
        return id;
    }

    @Override
    public DataNode get(String pathOrName) {
        return new NullDataNode(id.child(pathOrName));
    }

    @Override
    public boolean has(String pathOrName) {
        return false;
    }

    @Override
    public DataNode get(int idx) {
        return new NullDataNode(id.peer(idx));
    }

    @Override
    public TraceableValue getTraceableValue() {
        return new TraceableValue(null);
    }

    @Override
    public  E get() {
        return null;
    }

    @Override
    public boolean isList() {
        return false;
    }

    @Override
    public boolean isSingleValue() {
        return true;
    }

    @Override
    public List elements() {
        return Collections.singletonList(new NullDataNode(id.peer(0)));
    }

    @Override
    public Iterator iterator() {
        return elements().iterator();
    }

    @Override
    public int numberOfChildren() {
        return 0;
    }

    @Override
    public int numberOfElements() {
        return 0;
    }

    @Override
    public Map asMap() {
        return Collections.emptyMap();
    }

    @Override
    public boolean isNull() {
        return true;
    }

    @Override
    public String toString() {
        return "[null node]@" + id;
    }
}