/*
* Copyright 2004-2013 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.lealone.expression;
import org.lealone.command.Parser;
import org.lealone.constant.Constants;
import org.lealone.dbobject.FunctionAlias;
import org.lealone.dbobject.table.ColumnResolver;
import org.lealone.dbobject.table.TableFilter;
import org.lealone.engine.Session;
import org.lealone.util.StatementBuilder;
import org.lealone.value.DataType;
import org.lealone.value.Value;
import org.lealone.value.ValueArray;
import org.lealone.value.ValueNull;
import org.lealone.value.ValueResultSet;
/**
* This class wraps a user-defined function.
*/
public class JavaFunction extends Expression implements FunctionCall {
private final FunctionAlias functionAlias;
private final FunctionAlias.JavaMethod javaMethod;
private final Expression[] args;
public JavaFunction(FunctionAlias functionAlias, Expression[] args) {
this.functionAlias = functionAlias;
this.javaMethod = functionAlias.findJavaMethod(args);
this.args = args;
}
public Value getValue(Session session) {
return javaMethod.getValue(session, args, false);
}
public int getType() {
return javaMethod.getDataType();
}
public void mapColumns(ColumnResolver resolver, int level) {
for (Expression e : args) {
e.mapColumns(resolver, level);
}
}
public Expression optimize(Session session) {
boolean allConst = isDeterministic();
for (int i = 0, len = args.length; i < len; i++) {
Expression e = args[i].optimize(session);
args[i] = e;
allConst &= e.isConstant();
}
if (allConst) {
return ValueExpression.get(getValue(session));
}
return this;
}
public void setEvaluatable(TableFilter tableFilter, boolean b) {
for (Expression e : args) {
if (e != null) {
e.setEvaluatable(tableFilter, b);
}
}
}
public int getScale() {
return DataType.getDataType(getType()).defaultScale;
}
public long getPrecision() {
return Integer.MAX_VALUE;
}
public int getDisplaySize() {
return Integer.MAX_VALUE;
}
public String getSQL(boolean isDistributed) {
StatementBuilder buff = new StatementBuilder();
// TODO always append the schema once FUNCTIONS_IN_SCHEMA is enabled
if (functionAlias.getDatabase().getSettings().functionsInSchema
|| !functionAlias.getSchema().getName().equals(Constants.SCHEMA_MAIN)) {
buff.append(Parser.quoteIdentifier(functionAlias.getSchema().getName())).append('.');
}
buff.append(Parser.quoteIdentifier(functionAlias.getName())).append('(');
for (Expression e : args) {
buff.appendExceptFirst(", ");
buff.append(e.getSQL(isDistributed));
}
return buff.append(')').toString();
}
public void updateAggregate(Session session) {
for (Expression e : args) {
if (e != null) {
e.updateAggregate(session);
}
}
}
public String getName() {
return functionAlias.getName();
}
public int getParameterCount() {
return javaMethod.getParameterCount();
}
public ValueResultSet getValueForColumnList(Session session, Expression[] argList) {
Value v = javaMethod.getValue(session, argList, true);
return v == ValueNull.INSTANCE ? null : (ValueResultSet) v;
}
public Expression[] getArgs() {
return args;
}
public boolean isEverything(ExpressionVisitor visitor) {
switch (visitor.getType()) {
case ExpressionVisitor.DETERMINISTIC:
if (!isDeterministic()) {
return false;
}
// only if all parameters are deterministic as well
break;
case ExpressionVisitor.GET_DEPENDENCIES:
visitor.addDependency(functionAlias);
break;
default:
}
for (Expression e : args) {
if (e != null && !e.isEverything(visitor)) {
return false;
}
}
return true;
}
public int getCost() {
int cost = javaMethod.hasConnectionParam() ? 25 : 5;
for (Expression e : args) {
cost += e.getCost();
}
return cost;
}
public boolean isDeterministic() {
return functionAlias.isDeterministic();
}
public Expression[] getExpressionColumns(Session session) {
switch (getType()) {
case Value.RESULT_SET:
ValueResultSet rs = getValueForColumnList(session, getArgs());
return getExpressionColumns(session, rs.getResultSet());
case Value.ARRAY:
return getExpressionColumns(session, (ValueArray) getValue(session));
}
return super.getExpressionColumns(session);
}
public boolean isFast() {
return false;
}
}