net.orzo.IntermediateResults.java Source code

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Here is the source code for net.orzo.IntermediateResults.java

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/*
 * Copyright (C) 2013 Tomas Machalek
 *
 * 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 net.orzo;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import com.google.common.collect.*;

/**
 * Represents intermediate results of a single worker thread. These results are
 * merged before the <i>reduce</i> function is applied. It basically wraps
 * {@link Multimap} object and provides only required methods.
 *
 * @author Tomas Machalek <tomas.machalek@gmail.com>
 */
public class IntermediateResults {

    /**
     *
     */
    private final ListMultimap<String, Object> data;

    /**
     *
     */
    @Override
    public String toString() {
        return this.data.toString();
    }

    public IntermediateResults(ListMultimap<String, Object> data) {
        this.data = data;
    }

    /**
     *
     */
    public IntermediateResults() {
        this.data = ArrayListMultimap.create();
    }

    /**
     *
     * @return
     */
    public int size() {
        return this.data.size();
    }

    /**
     * Adds new value with specified key
     *
     * @param key
     * @param value any value as required by user's script
     * @throws NullPointerException if a null key is used
     */
    public void add(String key, Object value) {
        if (key == null) {
            throw new NullPointerException("Cannot add null key");
        }
        this.data.put(key, value);
    }

    public void addMultiple(String key, List<?> values) {
        this.data.putAll(key, values);
    }

    /**
     * @param key
     * @return
     */
    public List<?> remove(String key) {
        return new ArrayList<>(this.data.removeAll(key));
    }

    /**
     * Returns set of all keys (i.e. values are unique)
     */
    public Set<String> keys() {
        return this.data.keySet();
    }

    /**
     * @return
     */
    public int numKeys() {
        return this.data.keySet().size();
    }

    /**
     * Returns all results attached to the specified key
     */
    public List<Object> values(String key) {
        return this.data.get(key);
    }

    /**
     *
     */
    public Multimap<String, Object> getData() {
        return this.data;
    }

    /**
     * Adds all keys and values from another {@link IntermediateResults}
     * instance (just like putAll() in case of maps).
     *
     * @throws {@link IllegalArgumentException}
     */
    public synchronized void addAll(IntermediateResults another) {
        if (another == null) { // this.data.putAll would do this too but for
            // sure...
            throw new IllegalArgumentException("Cannot add null IntermediateResults");

        } else if (another == this) {
            throw new IllegalArgumentException("Cannot add self as a result to merge");
        }
        this.data.putAll(another.data);
    }

}