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tasks/astrid/common-src/com/todoroo/andlib/sql/QueryTemplate.java

118 lines
3.4 KiB
Java

package com.todoroo.andlib.sql;
import static com.todoroo.andlib.sql.SqlConstants.COMMA;
import static com.todoroo.andlib.sql.SqlConstants.GROUP_BY;
import static com.todoroo.andlib.sql.SqlConstants.LIMIT;
import static com.todoroo.andlib.sql.SqlConstants.ORDER_BY;
import static com.todoroo.andlib.sql.SqlConstants.SPACE;
import static com.todoroo.andlib.sql.SqlConstants.WHERE;
import static java.util.Arrays.asList;
import java.util.ArrayList;
/**
* Query Template returns a bunch of criteria that allows a query to be
* constructed
*
* @author Tim Su <tim@todoroo.com>
*
*/
public final class QueryTemplate {
private final ArrayList<Criterion> criterions = new ArrayList<Criterion>();
private final ArrayList<Join> joins = new ArrayList<Join>();
private final ArrayList<Field> groupBies = new ArrayList<Field>();
private final ArrayList<Order> orders = new ArrayList<Order>();
private final ArrayList<Criterion> havings = new ArrayList<Criterion>();
private Integer limit = null;
public QueryTemplate join(Join... join) {
joins.addAll(asList(join));
return this;
}
public QueryTemplate where(Criterion criterion) {
criterions.add(criterion);
return this;
}
public QueryTemplate groupBy(Field... groupBy) {
groupBies.addAll(asList(groupBy));
return this;
}
public QueryTemplate orderBy(Order... order) {
orders.addAll(asList(order));
return this;
}
@Override
public String toString() {
StringBuilder sql = new StringBuilder();
visitJoinClause(sql);
visitWhereClause(sql);
visitGroupByClause(sql);
visitOrderByClause(sql);
if(limit != null)
sql.append(LIMIT).append(SPACE).append(limit);
return sql.toString();
}
private void visitOrderByClause(StringBuilder sql) {
if (orders.isEmpty()) {
return;
}
sql.append(ORDER_BY);
for (Order order : orders) {
sql.append(SPACE).append(order).append(COMMA);
}
sql.deleteCharAt(sql.length() - 1).append(SPACE);
}
@SuppressWarnings("nls")
private void visitGroupByClause(StringBuilder sql) {
if (groupBies.isEmpty()) {
return;
}
sql.append(GROUP_BY);
for (Field groupBy : groupBies) {
sql.append(SPACE).append(groupBy).append(COMMA);
}
sql.deleteCharAt(sql.length() - 1).append(SPACE);
if (havings.isEmpty()) {
return;
}
sql.append("HAVING");
for (Criterion havingCriterion : havings) {
sql.append(SPACE).append(havingCriterion).append(COMMA);
}
sql.deleteCharAt(sql.length() - 1).append(SPACE);
}
private void visitWhereClause(StringBuilder sql) {
if (criterions.isEmpty()) {
return;
}
sql.append(WHERE);
for (Criterion criterion : criterions) {
sql.append(SPACE).append(criterion).append(SPACE);
}
}
private void visitJoinClause(StringBuilder sql) {
for (Join join : joins) {
sql.append(join).append(SPACE);
}
}
public QueryTemplate having(Criterion criterion) {
this.havings.add(criterion);
return this;
}
public QueryTemplate limit(int limitValue) {
this.limit = limitValue;
return this;
}
}