com.rabbitmq.jms.parse.sql.SqlEvaluator Maven / Gradle / Ivy
/* Copyright (c) 2014-2020 VMware, Inc. or its affiliates. All rights reserved. */
package com.rabbitmq.jms.parse.sql;
import static com.rabbitmq.jms.parse.ParseTreeTraverser.traverse;
import java.util.Map;
import com.rabbitmq.jms.parse.Evaluator;
/**
* A boolean evaluator for JMS Sql selector expressions.
*
*/
public class SqlEvaluator implements Evaluator {
private final SqlParseTree typedParseTree;
private final String errorMessage;
private final boolean evaluatorOk;
public SqlEvaluator(SqlParser parser, Map identTypes) {
if (parser.parseOk()) {
SqlParseTree parseTree = parser.parse();
if (this.evaluatorOk = canBeBool(SqlTypeChecker.deriveExpressionType(parseTree, identTypes))) {
this.typedParseTree = parseTree;
this.errorMessage = null;
} else {
this.errorMessage = "Type error in expression";
this.typedParseTree = null;
}
} else {
this.evaluatorOk = false;
this.typedParseTree = null;
this.errorMessage = parser.getErrorMessage();
}
}
private static boolean canBeBool(SqlExpressionType set) {
return (set == SqlExpressionType.BOOL || set == SqlExpressionType.ANY);
}
@Override
public boolean evaluate(Map env) {
if (this.evaluatorOk){
SqlEvaluatorVisitor eVisitor = new SqlEvaluatorVisitor(env);
if (traverse(this.typedParseTree, eVisitor)) {
Object val = this.typedParseTree.getNode().getExpValue().getValue();
if (val != null && val instanceof Boolean)
return (Boolean) val;
}
}
return false;
}
/**
* @return the type-checked parse tree used for evaluation; null if {@link #evaluatorOk()} is false.
*/
public SqlParseTree typedParseTree() {
return this.typedParseTree;
}
@Override
public boolean evaluatorOk() {
return this.evaluatorOk;
}
@Override
public String getErrorMessage() {
return this.errorMessage;
}
}