package org.couchbase.mock.views;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map.Entry;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONSerializer;
private final String body;
private final ScriptEngine engine;
public Reducer(ScriptEngine engine, String body) {
this.engine = engine;
this.body = body;
}
public ArrayList
execute(ArrayList rows, Configuration config)
throws ScriptException {
if (body.startsWith("_count")) {
return executeCount(rows, config);
} else if (body.startsWith("_sum")) {
return executeSum(rows, config);
} else if (body.startsWith("_stats")) {
return executeStats(rows, config);
} else {
return executeJS(rows, config);
}
}
public ArrayList keys = new ArrayList();
public ArrayList values = new ArrayList();
public void add(Object key, Object id, Object value) {
JSONArray json = new JSONArray();
json.add(key);
json.add(id);
keys.add(json);
values.add(value);
}
}
private HashMap<Object, ReduceEntry>
toReduceParams(ArrayList rows, Configuration config) {
HashMap<Object, ReduceEntry> res = new HashMap<Object, ReduceEntry>();
for (HashMap row : (ArrayList<HashMap>) rows) {
Object key = null;
if (config.isGroup()) {
key = row.get("key");
}
if (config.getGroupLevel() > 0) {
JSON json = JSONSerializer.toJSON(row.get("key"));
if (json instanceof JSONArray) {
ArrayList acc = new ArrayList();
for (int i = 0; i < config.getGroupLevel() && i < json.size(); ++i) {
acc.add(( (JSONArray) json ).get(i));
}
key = JSONArray.fromObject(acc).toString();
}
}
if (!res.containsKey(key)) {
res.put(key, new ReduceEntry());
}
res.get(key).add(row.get("key"), row.get("id"), row.get("value"));
}
return res;
}
private ArrayList
executeJS(ArrayList rows, Configuration config)
throws ScriptException {
ArrayList res = new ArrayList();
for (Entry<Object, ReduceEntry> entry : toReduceParams(rows, config).entrySet()) {
JSON group = JSONSerializer.toJSON(entry.getKey());
JSON params[] = new JSON[]{
JSONSerializer.toJSON(entry.getValue().keys),
JSONSerializer.toJSON(entry.getValue().values)
};
Object value = View.fromNativeObject(engine.eval("(" + body + ")(" + params[0].toString() + ", " + params[1].toString() + ", false)"));
HashMap reduced = new HashMap();
reduced.put("key", group);
reduced.put("value", value);
res.add(reduced);
}
return res;
}
private ArrayList
executeCount(ArrayList rows, Configuration config) {
ArrayList res = new ArrayList();
for (Entry<Object, ReduceEntry> entry : toReduceParams(rows, config).entrySet()) {
JSON group = JSONSerializer.toJSON(entry.getKey());
HashMap reduced = new HashMap();
reduced.put("key", group);
reduced.put("value", entry.getValue().values.size());
res.add(reduced);
}
return res;
}
private ArrayList
executeSum(ArrayList rows, Configuration config) {
ArrayList res = new ArrayList();
for (Entry<Object, ReduceEntry> entry : toReduceParams(rows, config).entrySet()) {
JSON group = JSONSerializer.toJSON(entry.getKey());
HashMap reduced = new HashMap();
reduced.put("key", group);
double sum = 0;
for (Object val : entry.getValue().values) {
sum += ( (Number) val ).doubleValue();
}
reduced.put("value", sum);
res.add(reduced);
}
return res;
}
private ArrayList
executeStats(ArrayList rows, Configuration config) {
ArrayList res = new ArrayList();
for (Entry<Object, ReduceEntry> entry : toReduceParams(rows, config).entrySet()) {
JSON group = JSONSerializer.toJSON(entry.getKey());
HashMap reduced = new HashMap();
reduced.put("key", group);
ArrayList values = entry.getValue().values;
double sum = 0;
int count = values.size();
double min = 0;
double max = 0;
double sumsqr = 0;
if (count > 0) {
min = max = ( (Number) values.get(0) ).doubleValue();
}
for (Object val : entry.getValue().values) {
double d = ( (Number) val ).doubleValue();
sum += d;
sumsqr += Math.pow(d, 2);
if (d < min) {
min = d;
}
if (d > max) {
max = d;
}
}
HashMap stats = new HashMap();
stats.put("sum", sum);
stats.put("max", max);
stats.put("min", min);
stats.put("count", count);
stats.put("sumsqr", sumsqr);
reduced.put("value", stats);
res.add(reduced);
}
return res;
}
}
