package simpledb.index.planner;import static simpledb.index.metadata.IndexInfo.*;import java.util.Iterator;import java.util.Map;import simpledb.record.RID;import simpledb.server.SimpleDB;import simpledb.tx.Transaction;import simpledb.index.Index;import simpledb.index.metadata.IndexInfo;import simpledb.parse.*;import simpledb.planner.*;import simpledb.query.*;/** * A modification of the basic update planner. * It dispatches each update statement to the corresponding * index planner. * It also now understands the "create index" statement. * @author Edward Sciore */public class IndexUpdatePlanner implements UpdatePlanner {		public int executeInsert(InsertData data, Transaction tx) {		Plan plan = new TablePlan(data.tableName(), tx);		// first, insert the record		UpdateScan s = (UpdateScan) plan.open();		s.insert();		RID rid = s.getRid();		// then modify each field, inserting an index record if appropriate		Map<String,IndexInfo> indexes = SimpleDB.mdMgr().getIndexInfo(data.tableName(), tx);		Iterator<Constant> valIter = data.vals().iterator();		for (String fldname : data.fields()) {			Constant val = valIter.next();			s.setVal(fldname, val);			IndexInfo ii = indexes.get(fldname);			if (ii != null) {				Index idx = ii.open(); 				idx.insert(val, rid);				idx.close();			}		}		s.close();		return 1;	}		public int executeDelete(DeleteData data, Transaction tx) {		String tblname = data.tableName();		Plan p = new TablePlan(tblname, tx);		p = new SelectPlan(p, data.pred());		Map<String,IndexInfo> indexes = SimpleDB.mdMgr().getIndexInfo(tblname, tx);		UpdateScan s = (UpdateScan) p.open();		int count = 0;		while(s.next()) {			// first, delete the record's RID from every index			RID rid = s.getRid();			for (String fldname : indexes.keySet()) {				Constant val = s.getVal(fldname);				Index idx = indexes.get(fldname).open();				idx.delete(val, rid);				idx.close();			}			// then delete the record			s.delete();			count++;		}		s.close();		return count;	}	public int executeModify(ModifyData data, Transaction tx) {		String tblname = data.tableName();		String fldname = data.targetField();		Plan p = new TablePlan(tblname, tx);		p = new SelectPlan(p, data.pred());		IndexInfo ii = SimpleDB.mdMgr().getIndexInfo(tblname, tx).get(fldname);		Index idx = (ii == null) ? null : ii.open();		UpdateScan s = (UpdateScan) p.open();		int count = 0;		while(s.next()) {			// first, update the record			Constant newval = data.newValue().evaluate(s);			Constant oldval = s.getVal(fldname);			s.setVal(data.targetField(), newval);			// then update the appropriate index, if it exists			if (idx != null) {				RID rid = s.getRid();				idx.delete(oldval, rid);				idx.insert(newval, rid);			}			count++;		}		if (idx != null) idx.close();		s.close();		return count;	}		public int executeCreateTable(CreateTableData data, Transaction tx) {		SimpleDB.mdMgr().createTable(data.tableName(), data.newSchema(), tx);		return 0;	}	public int executeCreateView(CreateViewData data, Transaction tx) {		SimpleDB.mdMgr().createView(data.viewName(), data.viewDef(), tx);		return 0;	}		public int executeCreateIndex(CreateIndexData data, Transaction tx) {		SimpleDB.mdMgr().createIndex(data.tableName(), data.fieldName(), BTREE, tx);		return 0;	}}