package org.h2.expression;
import org.h2.engine.Session;
import org.h2.expression.condition.Comparison;
import org.h2.index.IndexCondition;
import org.h2.message.DbException;
import org.h2.table.ColumnResolver;
import org.h2.table.TableFilter;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
import org.h2.value.ValueBoolean;
import org.h2.value.ValueCollectionBase;
import org.h2.value.ValueNull;
public class ValueExpression extends Expression {
private static final Object NULL = new ValueExpression(ValueNull.INSTANCE);
private static final Object DEFAULT = new ValueExpression(ValueNull.INSTANCE);
private final Value value;
private ValueExpression(Value value) {
this.value = value;
}
public static ValueExpression getNull() {
return (ValueExpression) NULL;
}
public static ValueExpression getDefault() {
return (ValueExpression) DEFAULT;
}
public static ValueExpression get(Value value) {
if (value == ValueNull.INSTANCE) {
return getNull();
}
return new ValueExpression(value);
}
@Override
public Value getValue(Session session) {
return value;
}
@Override
public TypeInfo getType() {
return value.getType();
}
@Override
public void createIndexConditions(Session session, TableFilter filter) {
if (value.getValueType() == Value.BOOLEAN) {
boolean v = ((ValueBoolean) value).getBoolean();
if (!v) {
filter.addIndexCondition(IndexCondition.get(Comparison.FALSE, null, this));
}
}
}
@Override
public Expression getNotIfPossible(Session session) {
return new Comparison(session, Comparison.EQUAL, this,
ValueExpression.get(ValueBoolean.FALSE));
}
@Override
public void mapColumns(ColumnResolver resolver, int level, int state) {
}
@Override
public Expression optimize(Session session) {
return this;
}
@Override
public boolean isConstant() {
return true;
}
@Override
public boolean isValueSet() {
return true;
}
@Override
public void setEvaluatable(TableFilter tableFilter, boolean b) {
}
@Override
public StringBuilder getSQL(StringBuilder builder, boolean alwaysQuote) {
if (this == DEFAULT) {
builder.append("DEFAULT");
} else {
value.getSQL(builder);
}
return builder;
}
@Override
public void updateAggregate(Session session, int stage) {
}
@Override
public boolean isEverything(ExpressionVisitor visitor) {
switch (visitor.getType()) {
case ExpressionVisitor.OPTIMIZABLE_AGGREGATE:
case ExpressionVisitor.DETERMINISTIC:
case ExpressionVisitor.READONLY:
case ExpressionVisitor.INDEPENDENT:
case ExpressionVisitor.EVALUATABLE:
case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID:
case ExpressionVisitor.NOT_FROM_RESOLVER:
case ExpressionVisitor.GET_DEPENDENCIES:
case ExpressionVisitor.QUERY_COMPARABLE:
case ExpressionVisitor.GET_COLUMNS1:
case ExpressionVisitor.GET_COLUMNS2:
return true;
default:
throw DbException.throwInternalError("type=" + visitor.getType());
}
}
@Override
public int getCost() {
return 0;
}
@Override
public Expression[] getExpressionColumns(Session session) {
int valueType = getType().getValueType();
if (valueType == Value.ARRAY || valueType == Value.ROW) {
return getExpressionColumns(session, (ValueCollectionBase) getValue(session));
}
return super.getExpressionColumns(session);
}
}