/**
* SqlJetCaseExpression.java
* Copyright (C) 2009-2010 TMate Software Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
package org.tmatesoft.sqljet.core.internal.schema;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.antlr.runtime.tree.CommonTree;
import org.tmatesoft.sqljet.core.SqlJetException;
import org.tmatesoft.sqljet.core.schema.ISqlJetCaseExpression;
import org.tmatesoft.sqljet.core.schema.ISqlJetExpression;
/**
* @author TMate Software Ltd.
* @author Dmitry Stadnik (dtrace@seznam.cz)
*/
public class SqlJetCaseExpression extends SqlJetExpression implements ISqlJetCaseExpression {
private final ISqlJetExpression expression, defaultValue;
private final List<ISqlJetExpression> conditions, values;
public SqlJetCaseExpression(CommonTree ast) throws SqlJetException {
assert "case".equalsIgnoreCase(ast.getText());
int idx = 0;
CommonTree child = (CommonTree) ast.getChild(idx++);
if ("when".equalsIgnoreCase(child.getText())) {
expression = null;
} else {
expression = create(child);
child = (CommonTree) ast.getChild(idx++);
}
List<ISqlJetExpression> conditions = new ArrayList<ISqlJetExpression>();
List<ISqlJetExpression> values = new ArrayList<ISqlJetExpression>();
while (idx < ast.getChildCount()) {
if ("when".equalsIgnoreCase(child.getText())) {
ISqlJetExpression condition = create((CommonTree) child.getChild(0));
ISqlJetExpression value = create((CommonTree) child.getChild(1));
conditions.add(condition);
values.add(value);
child = (CommonTree) ast.getChild(idx++);
} else {
break;
}
}
this.conditions = Collections.unmodifiableList(conditions);
this.values = Collections.unmodifiableList(values);
if (idx < child.getChildCount()) {
defaultValue = create(child);
} else {
defaultValue = null;
}
}
public ISqlJetExpression getExpression() {
return expression;
}
public List<ISqlJetExpression> getConditions() {
return conditions;
}
public List<ISqlJetExpression> getValues() {
return values;
}
public ISqlJetExpression getDefaultValue() {
return defaultValue;
}
@Override
public String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append("CASE ");
if (getExpression() != null) {
buffer.append(getExpression());
buffer.append(' ');
}
for (int idx = 0; idx < getConditions().size(); idx++) {
buffer.append("WHEN ");
buffer.append(getConditions().get(idx));
buffer.append(' ');
buffer.append(getValues().get(idx));
buffer.append(' ');
}
if (getDefaultValue() != null) {
buffer.append("ELSE ");
buffer.append(getDefaultValue());
buffer.append(' ');
}
buffer.append("END");
return buffer.toString();
}
}