BaseSorter.java

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package com.google.refine.sorting;

import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.google.refine.expr.EvalError;
import com.google.refine.model.Project;
import com.google.refine.sorting.Criterion.KeyMaker;

abstract public class BaseSorter {
    protected Criterion[] _criteria;
    protected KeyMaker[] _keyMakers;
    protected ComparatorWrapper[] _comparatorWrappers;
    protected List<Object[]> _keys;

    public class ComparatorWrapper {
        final public int criterionIndex;
        final protected int multiplier;

        public ComparatorWrapper(int criterionIndex) {
            this.criterionIndex = criterionIndex;
            this.multiplier = _criteria[criterionIndex].reverse ? -1 : 1;
        }

        public Object getKey(Project project, Object o, int index) {
            while (index >= _keys.size()) {
                _keys.add(null);
            }

            Object[] keys = _keys.get(index);
            if (keys == null) {
                keys = makeKeys(project, o, index);
                _keys.set(index, keys);
            }
            return keys[criterionIndex];
        }

        public int compare(Project project, Object o1, int i1, Object o2, int i2) {
            Criterion c = _criteria[criterionIndex];
            Object key1 = getKey(project, o1, i1);
            Object key2 = getKey(project, o2, i2);

            if (key1 == null) {
                if (key2 == null) {
                    return 0;
                } else if (key2 instanceof EvalError) {
                    return c.blankPosition - c.errorPosition;
                } else {
                    return c.blankPosition;
                }
            } else if (key1 instanceof EvalError) {
                if (key2 == null) {
                    return c.errorPosition - c.blankPosition;
                } else if (key2 instanceof EvalError) {
                    return 0;
                } else {
                    return c.errorPosition;
                }
            } else {
                if (key2 == null) {
                    return -c.blankPosition;
                } else if (key2 instanceof EvalError) {
                    return -c.errorPosition;
                } else {
                    return _keyMakers[criterionIndex].compareKeys(key1, key2) * multiplier;
                }
            }
        }
    }

    public void initializeFromJSON(Project project, JSONObject obj) throws JSONException {
        if (obj.has("criteria") && !obj.isNull("criteria")) {
            JSONArray a = obj.getJSONArray("criteria");
            int count = a.length();

            _criteria = new Criterion[count];
            _keyMakers = new KeyMaker[count];
            _comparatorWrappers = new ComparatorWrapper[count];

            for (int i = 0; i < count; i++) {
                JSONObject obj2 = a.getJSONObject(i);

                _criteria[i] = createCriterionFromJSON(project, obj2);
                _keyMakers[i] = _criteria[i].createKeyMaker();
                _comparatorWrappers[i] = new ComparatorWrapper(i);
            }
        } else {
            _criteria = new Criterion[0];
            _keyMakers = new KeyMaker[0];
            _comparatorWrappers = new ComparatorWrapper[0];
        }
    }

    public boolean hasCriteria() {
        return _criteria != null && _criteria.length > 0;
    }

    protected Criterion createCriterionFromJSON(Project project, JSONObject obj) throws JSONException {
        String valueType = "string";
        if (obj.has("valueType") && !obj.isNull("valueType")) {
            valueType = obj.getString("valueType");
        }

        Criterion c = null;
        if ("boolean".equals(valueType)) {
            c = new BooleanCriterion();
        } else if ("date".equals(valueType)) {
            c = new DateCriterion();
        } else if ("number".equals(valueType)) {
            c = new NumberCriterion();
        } else {
            c = new StringCriterion();
        }

        c.initializeFromJSON(project, obj);
        return c;
    }

    abstract protected Object makeKey(
            Project project, KeyMaker keyMaker, Criterion c, Object o, int index);

    protected Object[] makeKeys(Project project, Object o, int index) {
        Object[] keys = new Object[_keyMakers.length];
        for (int i = 0; i < keys.length; i++) {
            keys[i] = makeKey(project, _keyMakers[i], _criteria[i], o, index);
        }
        return keys;
    }

    protected int compare(Project project, Object o1, int i1, Object o2, int i2) {
        int c = 0;
        for (int i = 0; c == 0 && i < _comparatorWrappers.length; i++) {
            c = _comparatorWrappers[i].compare(project, o1, i1, o2, i2);
        }
        return c;
    }
}