/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression;
import org.h2.command.Prepared;
import org.h2.engine.SessionLocal;
import org.h2.schema.Sequence;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
/**
* Wraps a sequence when used in a statement.
*/
public final class SequenceValue extends Operation0 {
private final Sequence sequence;
private final boolean current;
private final Prepared prepared;
/**
* Creates new instance of NEXT VALUE FOR expression.
*
* @param sequence
* the sequence
* @param prepared
* the owner command, or {@code null}
*/
public SequenceValue(Sequence sequence, Prepared prepared) {
this.sequence = sequence;
current = false;
this.prepared = prepared;
}
/**
* Creates new instance of CURRENT VALUE FOR expression.
*
* @param sequence
* the sequence
*/
public SequenceValue(Sequence sequence) {
this.sequence = sequence;
current = true;
prepared = null;
}
@Override
public Value getValue(SessionLocal session) {
return current ? session.getCurrentValueFor(sequence) : session.getNextValueFor(sequence, prepared);
}
@Override
public TypeInfo getType() {
return sequence.getDataType();
}
@Override
public StringBuilder getUnenclosedSQL(StringBuilder builder, int sqlFlags) {
builder.append(current ? "CURRENT" : "NEXT").append(" VALUE FOR ");
return sequence.getSQL(builder, sqlFlags);
}
@Override
public boolean isEverything(ExpressionVisitor visitor) {
switch (visitor.getType()) {
case ExpressionVisitor.DETERMINISTIC:
case ExpressionVisitor.INDEPENDENT:
case ExpressionVisitor.QUERY_COMPARABLE:
return false;
case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID:
visitor.addDataModificationId(sequence.getModificationId());
return true;
case ExpressionVisitor.GET_DEPENDENCIES:
visitor.addDependency(sequence);
return true;
case ExpressionVisitor.READONLY:
return current;
default:
return true;
}
}
@Override
public int getCost() {
return 1;
}
}