Forgot the main evaluator class in the previous commit. Hee.
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Par Winzell
@@ -0,0 +1,338 @@
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//
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// $Id: ExpressionEvaluator.java 377 2009-01-08 02:31:28Z samskivert $
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//
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// Depot library - a Java relational persistence library
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// Copyright (C) 2006-2008 Michael Bayne and Pär Winzell
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.samskivert.depot.impl;
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import java.lang.reflect.Field;
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import java.util.Date;
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import com.samskivert.depot.Key;
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import com.samskivert.depot.PersistentRecord;
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import com.samskivert.depot.clause.FieldDefinition;
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import com.samskivert.depot.clause.ForUpdate;
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import com.samskivert.depot.clause.FromOverride;
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import com.samskivert.depot.clause.GroupBy;
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import com.samskivert.depot.clause.InsertClause;
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import com.samskivert.depot.clause.Join;
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import com.samskivert.depot.clause.Limit;
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import com.samskivert.depot.clause.OrderBy;
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import com.samskivert.depot.clause.SelectClause;
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import com.samskivert.depot.clause.WhereClause;
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import com.samskivert.depot.expression.ColumnExp;
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import com.samskivert.depot.expression.EpochSeconds;
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import com.samskivert.depot.expression.FunctionExp;
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import com.samskivert.depot.expression.LiteralExp;
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import com.samskivert.depot.expression.SQLExpression;
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import com.samskivert.depot.expression.SQLExpression.NoValue;
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import com.samskivert.depot.expression.ValueExp;
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import com.samskivert.depot.operator.Conditionals.Case;
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import com.samskivert.depot.operator.Conditionals.Exists;
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import com.samskivert.depot.operator.Conditionals.FullText;
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import com.samskivert.depot.operator.Conditionals.In;
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import com.samskivert.depot.operator.Conditionals.IsNull;
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import com.samskivert.depot.operator.Logic.Not;
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import com.samskivert.depot.operator.SQLOperator.BinaryOperator;
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import com.samskivert.depot.operator.SQLOperator.MultiOperator;
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import com.samskivert.depot.impl.clause.CreateIndexClause;
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import com.samskivert.depot.impl.clause.DeleteClause;
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import com.samskivert.depot.impl.clause.DropIndexClause;
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import com.samskivert.depot.impl.clause.UpdateClause;
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import com.samskivert.util.ArrayUtil;
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import com.samskivert.util.Tuple;
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import static com.samskivert.depot.Log.log;
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/**
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* Enumerates visitation methods for every possible SQL expression type.
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*/
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public class ExpressionEvaluator
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implements ExpressionVisitor<Object>
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{
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public <T extends PersistentRecord> ExpressionEvaluator (Class<T> pClass, T pRec)
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{
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_pClass = pClass;
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_pRec = pRec;
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}
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public Object visit (FunctionExp functionExp)
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{
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SQLExpression[] arguments = functionExp.getArguments();
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Object[] values = new Object[functionExp.getArguments().length];
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for (int ii = 0; ii < values.length; ii ++) {
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values[ii] = arguments[ii].accept(this);
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if (values[ii] instanceof NoValue) {
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return values[ii];
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}
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}
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if ("lower".equalsIgnoreCase(functionExp.getFunction())) {
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if (values.length == 1 && values[0] instanceof String) {
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return ((String) values[0]).toLowerCase();
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}
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}
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return new NoValue("Bad Function: " + functionExp);
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}
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public Object visit (EpochSeconds epochSeconds)
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{
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Object result = epochSeconds.getArgument().accept(this);
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if (result instanceof Date) {
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return ((Date) result).getTime();
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}
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return new NoValue("Bad EpochSeconds: " + epochSeconds);
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}
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public Object visit (MultiOperator multiOperator)
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{
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SQLExpression[] operands = multiOperator.getOperands();
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Object[] values = new Object[operands.length];
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for (int ii = 0; ii < operands.length; ii ++) {
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values[ii] = operands[ii].accept(this);
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if (values[ii] instanceof NoValue) {
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return values[ii];
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}
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}
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return multiOperator.evaluate(values);
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}
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public Object visit (BinaryOperator binaryOperator)
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{
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Object left = binaryOperator.getLeftHandSide().accept(this);
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Object right = binaryOperator.getRightHandSide().accept(this);
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if (left instanceof NoValue) {
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return left;
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}
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if (right instanceof NoValue) {
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return right;
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}
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return binaryOperator.evaluate(left, right);
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}
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public Object visit (IsNull isNull)
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{
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Object operand = isNull.getColumn().accept(this);
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return (operand instanceof NoValue) ? operand : operand != null;
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}
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public Object visit (In in)
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{
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Object operand = in.getColumn().accept(this);
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return (operand instanceof NoValue) ? operand :
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-1 != ArrayUtil.indexOf(in.getValues(), operand);
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}
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public Object visit (FullText.Match match)
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{
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return new NoValue("Full Text Match not implemented");
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}
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public Object visit (FullText.Rank rank)
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{
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return new NoValue("Full Text Match not implemented");
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}
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public Object visit (Case caseExp)
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{
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for (Tuple<SQLExpression, SQLExpression> exp : caseExp.getWhenExps()) {
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Object result = exp.left.accept(this);
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if (result instanceof NoValue || !(result instanceof Boolean)) {
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return new NoValue("Failed to evaluate case: " + exp.left + " -> " + result);
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}
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if (((Boolean) result).booleanValue()) {
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return exp.right.accept(this);
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}
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}
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SQLExpression elseExp = caseExp.getElseExp();
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if (elseExp != null) {
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return elseExp.accept(this);
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}
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return null;
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}
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public Object visit (ColumnExp columnExp)
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{
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Class<? extends PersistentRecord> pClass = columnExp.getPersistentClass();
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if (pClass != _pClass) {
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// TODO: Accept Class -> Record mapping
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return new NoValue("Column lookup on unknown persistent class: " + pClass);
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}
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try {
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Field field = pClass.getField(columnExp.getField());
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if (field == null) {
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log.warning("Couldn't locate field on class", "field", columnExp.getField(),
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"class", pClass);
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return new NoValue("Internal Error");
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}
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return field.get(_pRec);
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} catch (Exception e) {
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log.warning("Failed to retrieve field value", "field", columnExp.getField(), e);
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return new NoValue("Internal Error");
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}
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}
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public Object visit (Not not)
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{
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Object result = not.getCondition().accept(this);
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if (result instanceof NoValue) {
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return result;
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}
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if (result instanceof Boolean) {
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return !((Boolean) result).booleanValue();
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}
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return new NoValue("Boolean negation of non-boolean value: " + result);
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}
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public Object visit (LiteralExp literalExp)
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{
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return new NoValue("Cannot evaluate LiteralExp: " + literalExp);
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}
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public Object visit (ValueExp valueExp)
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{
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return valueExp.getValue();
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}
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public Object visit (WhereClause where)
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{
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Object result = where.getWhereExpression().accept(this);
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if (result instanceof NoValue || result instanceof Boolean) {
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return result;
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}
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return new NoValue("Non-boolean result from Where expression: " + result);
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}
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public Object visit (Key.Expression<? extends PersistentRecord> key)
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{
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Class<? extends PersistentRecord> pClass = key.getPersistentClass();
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if (pClass != _pClass) {
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// TODO: Accept Class -> Record mapping
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return new NoValue("Column lookup on unknown persistent class: " + pClass);
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}
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String[] keyFields = DepotUtil.getKeyFields(pClass);
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Comparable<?>[] values = key.getValues();
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for (int ii = 0; ii < keyFields.length; ii ++) {
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Object value;
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try {
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value = pClass.getDeclaredField(keyFields[ii]).get(_pRec);
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} catch (Exception e) {
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log.warning("Failed to retrieve field value", "field", keyFields[ii], e);
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return new NoValue("Internal Error");
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}
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if (value == null) {
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if (values[ii] != null) {
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return false;
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}
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} else if (!value.equals(values[ii])) {
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return false;
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}
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}
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return true;
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}
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public Object visit (Exists<? extends PersistentRecord> exists)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + exists);
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}
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public Object visit (GroupBy groupBy)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + groupBy);
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}
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public Object visit (ForUpdate forUpdate)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + forUpdate);
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}
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public Object visit (OrderBy orderBy)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + orderBy);
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}
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public Object visit (Join join)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + join);
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}
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public Object visit (Limit limit)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + limit);
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}
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public Object visit (FieldDefinition fieldOverride)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + fieldOverride);
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}
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public Object visit (FromOverride fromOverride)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + fromOverride);
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}
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public Object visit (SelectClause<? extends PersistentRecord> selectClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + selectClause);
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}
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public Object visit (UpdateClause<? extends PersistentRecord> updateClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + updateClause);
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}
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public Object visit (DeleteClause deleteClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + deleteClause);
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}
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public Object visit (InsertClause insertClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + insertClause);
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}
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public Object visit (CreateIndexClause createIndexClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + createIndexClause);
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}
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public Object visit (DropIndexClause<? extends PersistentRecord> dropIndexClause)
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{
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throw new IllegalArgumentException("Can't evaluate expression: " + dropIndexClause);
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}
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public static Double numerical (Object o)
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{
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return (o instanceof Number) ? ((Number) o).doubleValue() : null;
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}
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public static Long integral (Object o)
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{
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return ((o instanceof Integer) || (o instanceof Long)) ? ((Number) o).longValue() : null;
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}
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protected Class<? extends PersistentRecord> _pClass;
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protected PersistentRecord _pRec;
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}
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