com.rabbitmq.jms.parse.sql.SqlEvaluatorVisitor Maven / Gradle / Ivy
/* Copyright (c) 2014 Pivotal Software, Inc. All rights reserved. */
package com.rabbitmq.jms.parse.sql;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.rabbitmq.jms.parse.Visitor;
/**
* This visitor evaluates an SQL expression in the form of an {@link SqlParseTree} by traversing the
* nodes of the tree and building expression values of parent nodes from values of the children.
* It is, in essence, an interpreter. It takes, as instantiation parameter, a context in which
* the expression is evaluated (a map from identifiers to values).
*
* The UNKNOWN value is represented by null.
*
*/
class SqlEvaluatorVisitor implements Visitor {
private final Map env;
SqlEvaluatorVisitor(Map env) {
this.env = env; // identifier values
}
@Override
public boolean visitBefore(SqlTreeNode parent, SqlTreeNode[] children) {
// nothing happens on before pass
return true;
}
@Override
public boolean visitAfter(SqlTreeNode parent, SqlTreeNode[] children) {
Object[] childVals = new Object[children.length];
for (int i=0; i env, SqlTreeNode parent, Object[] vals) {
switch(parent.treeType()) {
case CONJUNCTION: return logicalAnd(vals[0], vals[1]);
case DISJUNCTION: return logicalOr(vals[0], vals[1]);
case LEAF: return leafValue(parent.value(), env);
case LIST: return parent.value().getList();
case PATTERN1: return pattern(vals[0], null);
case PATTERN2: return pattern(vals[0], vals[1]);
case POSTFIXUNARYOP:
case PREFIXUNARYOP:
case TERNARYOP:
case BINARYOP: return operationValue(parent.value().type(), vals);
default: return null;
}
}
private static final Pattern pattern(Object o1, Object o2) {
if (!isString(o1)) return null;
String pattString = Pattern.quote((String) o1); // enLiteral everything to start with
boolean noEscape = true;
char escChar = ' '; // ignored if noEscape==true
if (isString(o2) && ((String)o2).length()>0) {
noEscape=false;
escChar=((String)o2).charAt(0);
}
boolean nextAsis = false;
StringBuilder sp = new StringBuilder();
for (char ch : pattString.toCharArray()) {
if (nextAsis) { sp.append(ch); nextAsis = false; }
else if (!noEscape && ch==escChar) nextAsis = true;
else if (ch=='_') sp.append('.');
else if (ch=='%') sp.append(".*");
else sp.append(ch);
}
return Pattern.compile(sp.toString());
}
private static final Object operationValue(SqlTokenType op, Object[] vals) {
switch (op) {
case NOT_BETWEEN: return notBetween(vals[0], vals[1], vals[2]);
case BETWEEN: return logicalNot(notBetween(vals[0], vals[1], vals[2]));
case CMP_EQ: return equals(vals[0], vals[1]);
case CMP_NEQ: return logicalNot(equals(vals[0], vals[1]));
case CMP_GT: return greaterThan(vals[0], vals[1]);
case CMP_LTEQ: return logicalNot(greaterThan(vals[0], vals[1]));
case CMP_LT: return greaterThan(vals[1], vals[0]);
case CMP_GTEQ: return logicalNot(greaterThan(vals[1], vals[0]));
case IN: return in(vals[0], vals[1]);
case NOT_IN: return logicalNot(in(vals[0], vals[1]));
case LIKE: return like(vals[0], vals[1]);
case NOT_LIKE: return logicalNot(like(vals[0], vals[1]));
case NULL: return isNull(vals[0]);
case NOT_NULL: return logicalNot(isNull(vals[0]));
case OP_DIV: return divide(vals[0], vals[1]);
// OP_MINUS may be unary prefix or binary op:
case OP_MINUS: return (vals.length>1 ? subtract(vals[0], vals[1]) : subtract(0L, vals[0]));
case OP_MULT: return multiply(vals[0], vals[1]);
// OP_PLUS may be unary prefix or binary op:
case OP_PLUS: return (vals.length>1 ? add(vals[0], vals[1]) : add(vals[0], 0L));
case NOT: return logicalNot(vals[0]);
default: return null;
}
}
private static final Boolean like(Object o1, Object o2) {
// assert: o1 is an identifier value -- so may be any type or null;
if (!isString(o1)) return null;
if (!isPattern(o2)) return null;
Matcher matcher = ((Pattern)o2).matcher((String)o1);
return matcher.matches();
}
private static final Object add(Object o1, Object o2) {
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) + toLong(o2);
else if(isDouble(o2)) return new Double(o1.toString()) + toDouble(o2);
else return null;
} else if (isDouble(o1)) {
if (isDouble(o2)) return toDouble(o1) + toDouble(o2);
else if (isLong(o2)) return toDouble(o1) + new Double(o2.toString());
else return null;
}
return null;
}
private static final long toLong(Object o) {
// isLong(o) is true
if (o instanceof Long) return (Long) o;
return ((Integer) o).longValue();
}
private static final boolean toBool(Object o) {
// isBool(o) is true
return (Boolean) o;
}
private static final double toDouble(Object o) {
// isDouble(o) is true
if (o instanceof Double) return (Double) o;
return ((Float) o).doubleValue();
}
private static final Object subtract(Object o1, Object o2) {
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) - toLong(o2);
else if(isDouble(o2)) return new Double(o1.toString()) - toDouble(o2);
else return null;
} else if (isDouble(o1)) {
if (isDouble(o2)) return toDouble(o1) - toDouble(o2);
else if (isLong(o2)) return toDouble(o1) - new Double(o2.toString());
else return null;
}
return null;
}
private static final Object multiply(Object o1, Object o2) {
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) * toLong(o2);
else if(isDouble(o2)) return new Double(o1.toString()) * toDouble(o2);
else return null;
} else if (isDouble(o1)) {
if (isDouble(o2)) return toDouble(o1) * toDouble(o2);
else if (isLong(o2)) return toDouble(o1) * new Double(o2.toString());
else return null;
}
return null;
}
private static final Object divide(Object o1, Object o2) {
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) / toLong(o2);
else if(isDouble(o2)) return new Double(o1.toString()) / toDouble(o2);
else return null;
} else if (isDouble(o1)) {
if (isDouble(o2)) return toDouble(o1) / toDouble(o2);
else if (isLong(o2)) return toDouble(o1) / new Double(o2.toString());
else return null;
}
return null;
}
private static final Boolean in(Object o1, Object o2) {
if (o1==null || o2==null) return null;
if (!(o1 instanceof String)) return null;
@SuppressWarnings("unchecked") // assert: this is a type-checked tree being visited
List list = (List)o2;
return list.contains((String)o1);
}
private static final Boolean greaterThan(Object o1, Object o2) {
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) > toLong(o2);
else if(isDouble(o2)) return new Double(o1.toString()) > toDouble(o2);
else return null;
} else if (isDouble(o1)) {
if (isDouble(o2)) return toDouble(o1) > toDouble(o2);
else if (isLong(o2)) return toDouble(o1) > new Double(o2.toString());
else return null;
}
return null;
}
private static final Boolean equals(Object o1, Object o2) {
if (o1==null || o2==null) return null;
if (o1 instanceof String) return o1.equals(o2);
if (isBool(o1) && isBool(o2)) return toBool(o1) == toBool(o2);
if (isLong(o1)) {
if (isLong(o2)) return toLong(o1) == toLong(o2);
else if (isDouble(o2)) return (double)toLong(o1) == toDouble(o2);
} else if (isDouble(o1)) {
if (isLong(o2)) return toDouble(o1) == (double)toLong(o2);
else if (isDouble(o2)) return toDouble(o1) == toDouble(o2);
}
return false;
}
private static final boolean isNull(Object o) {
return o==null;
}
private static final Boolean notBetween(Object o1, Object o2, Object o3) {
return logicalOr(greaterThan(o2, o1), greaterThan(o1, o3));
}
private static final Object leafValue(SqlToken value, Map env) {
switch (value.type()) {
case TRUE: return true;
case FALSE: return false;
case FLOAT: return value.getFloat();
case HEX: return value.getHex();
case INT: return value.getLong();
case LIST: return value.getList();
case IDENT: return env==null ? null : env.get(value.getIdent());
case STRING: return value.getString();
default:
return null;
}
}
/**
* Implements the three-valued logic as in JMS spec
*/
private static final Boolean logicalAnd(Object o1, Object o2) {
if (isBool(o1) && !(Boolean) o1) return false;
if (isBool(o2) && !(Boolean) o2) return false;
if (isBool(o1) && (Boolean) o1 && isBool(o2) && (Boolean) o2) return true;
return null;
}
/**
* Implements the three-valued logic as in JMS spec
*/
private static final Boolean logicalOr(Object o1, Object o2) {
if (isBool(o1) && (Boolean) o1) return true;
if (isBool(o2) && (Boolean) o2) return true;
if (isBool(o1) && !(Boolean) o1 && isBool(o2) && !(Boolean) o2) return false;
return null;
}
/**
* Implements the three-valued logic as in JMS spec
*/
private static final Boolean logicalNot(Object o) {
return (!isBool(o) ? null : !(Boolean) o);
}
private static final boolean isLong(Object o) {
return o!=null && o instanceof Long || o instanceof Integer;
}
private static final boolean isDouble(Object o) {
return o!=null && o instanceof Double || o instanceof Float;
}
private static final boolean isString(Object o) {
return o!=null && o instanceof String;
}
private static final boolean isBool(Object o) {
return o!=null && o instanceof Boolean;
}
private static final boolean isPattern(Object o) {
return o!=null && o instanceof Pattern;
}
}