com.rabbitmq.jms.parse.sql.SqlExpressionValue Maven / Gradle / Ivy
/* Copyright (c) 2014 Pivotal Software, Inc. All rights reserved. */
package com.rabbitmq.jms.parse.sql;
import java.util.List;
/**
* A selector expression value in a parse tree. This object holds the
* expression value and the expression type for both the {@link SqlCompiler}
* and {@link SqlEvaluator} visitors. The type and value are both settable and gettable.
*
*
*
*/
class SqlExpressionValue {
private SqlExpressionType expType;
private Object expValue;
// INVARIANT: the expValue must either be null or be an object of type consistent with expType;
// one of:
// NOT_SET(null), BOOL(Boolean), ARITH(Float, Double, Integer, Long), STRING(String), LIST(List)
// but not INVALID.
// ANY can be any of the above, except LIST.
SqlExpressionValue() {
this(SqlExpressionType.NOT_SET, null);
}
private SqlExpressionValue(SqlExpressionType expType, Object expValue) {
this.expType = expType;
this.expValue = filterValType(expType, expValue);
}
SqlExpressionType getType() {
return this.expType;
}
void setType(SqlExpressionType expType) {
this.expType = expType;
this.expValue = null;
}
Object getValue() {
return this.expValue;
}
void setValue(Object val) {
this.expValue = filterValType(this.expType, val);
}
private static final Object filterValType(SqlExpressionType type, Object val) {
if (val == null) return null;
switch (type) {
case ANY: return filter(val, String.class, Boolean.class, Float.class, Double.class, Integer.class, Long.class);
case ARITH: return filter(val, Float.class, Double.class, Integer.class, Long.class);
case BOOL: return filter(val, Boolean.class);
case LIST: return filter(val, List.class);
case STRING: return filter(val, String.class);
default: return null;
}
}
private static final Object filter(Object val, Class ... clzs) {
for (Class clz : clzs) if (clz.isInstance(val)) return val;
return null;
}
@Override
public String toString() {
return String.format("<%s: %s>", this.expType, this.expValue);
}
}