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Added QueryBuilder.delete() along with a bunch of sanity checking. I considered

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having a separate deleteFrom(record).where(...).delete() builder, but
from(record).where(...).delete() was so much nicer that I decided that
preventing the specification of invalid clauses could be deferred from compile
to runtime.

I could do some fiddly things with return types and have from() return a
builder that then subsequently pigeon-holed you into deletability or not
depending on whether you called things like orderBy(), but to do so in Java
would require that I override every method to specialize its return type, which
presents something of a maintenance annoyance.
This commit is contained in:
Michael Bayne
2010-12-07 23:41:27 +00:00
parent 1e86fba829
commit fca5cb2386
1 changed files with 68 additions and 0 deletions
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src/main/java/com/samskivert/depot/QueryBuilder.java
+68
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@@ -81,6 +81,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> where (SQLExpression... exprs)
{
requireNull(_where, "Where clause is already configured.");
switch (exprs.length) {
case 0:
throw new IllegalArgumentException("Must supply at least one expression.");
@@ -100,6 +101,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> where (ColumnExp column, Comparable<?> value)
{
requireNull(_where, "Where clause is already configured.");
_where = new Where(column, value);
return this;
}
@@ -111,6 +113,7 @@ public class QueryBuilder<T extends PersistentRecord>
public QueryBuilder<T> where (ColumnExp index1, Comparable<?> value1,
ColumnExp index2, Comparable<?> value2)
{
requireNull(_where, "Where clause is already configured.");
_where = new Where(index1, value1, index2, value2);
return this;
}
@@ -120,6 +123,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> join (ColumnExp left, ColumnExp right)
{
requireNull(_join, "Join clause is already configured.");
_join = new Join(left, right);
return this;
}
@@ -129,6 +133,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> groupBy (SQLExpression... exprs)
{
requireNull(_groupBy, "GroupBy clause is already configured.");
_groupBy = new GroupBy(exprs);
return this;
}
@@ -138,6 +143,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> randomOrder ()
{
requireNull(_orderBy, "OrderBy clause is already configured.");
_orderBy = OrderBy.random();
return this;
}
@@ -147,6 +153,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> ascending (SQLExpression value)
{
requireNull(_orderBy, "OrderBy clause is already configured.");
_orderBy = OrderBy.ascending(value);
return this;
}
@@ -156,6 +163,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> descending (SQLExpression value)
{
requireNull(_orderBy, "OrderBy clause is already configured.");
_orderBy = OrderBy.descending(value);
return this;
}
@@ -165,6 +173,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> limit (int count)
{
requireNull(_limit, "Limit clause is already configured.");
_limit = new Limit(0, count);
return this;
}
@@ -174,6 +183,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> limit (int offset, int count)
{
requireNull(_limit, "Limit clause is already configured.");
_limit = new Limit(offset, count);
return this;
}
@@ -183,6 +193,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> override (Class<? extends PersistentRecord> fromClass)
{
requireNull(_fromOverride, "FromOverride clause is already configured.");
_fromOverride = new FromOverride(fromClass);
return this;
}
@@ -193,6 +204,7 @@ public class QueryBuilder<T extends PersistentRecord>
public QueryBuilder<T> override (Class<? extends PersistentRecord> fromClass1,
Class<? extends PersistentRecord> fromClass2)
{
requireNull(_fromOverride, "FromOverride clause is already configured.");
_fromOverride = new FromOverride(fromClass1, fromClass2);
return this;
}
@@ -202,6 +214,7 @@ public class QueryBuilder<T extends PersistentRecord>
*/
public QueryBuilder<T> forUpdate ()
{
requireNull(_forUpdate, "ForUpdate clause is already configured.");
_forUpdate = new ForUpdate();
return this;
}
@@ -248,6 +261,47 @@ public class QueryBuilder<T extends PersistentRecord>
return _repo.load(CountRecord.class, _cache, getClauseArray()).count;
}
/**
* Deletes the records that match the configured query clauses. Note that only the where
* clauses are used to evaluate a deletion. Attempts to use other clauses will result in
* failure.
*
* @return the number of rows deleted by this action.
*
* @throws DatabaseException if any problem is encountered communicating with the database.
*/
public int delete ()
{
requireNotNull(_where, "Where clause must be specified for delete.");
requireNull(_join, "Join clause not supported by delete.");
requireNull(_orderBy, "OrderBy clause not applicable for delete.");
requireNull(_groupBy, "GroupBy clause not applicable for delete.");
requireNull(_limit, "Limit clause not supported by delete.");
requireNull(_fromOverride, "FromOverride clause not applicable for delete.");
requireNull(_forUpdate, "ForUpdate clause not supported by delete.");
return _repo.deleteAll(_pclass, _where);
}
/**
* Deletes the records that match the configured query clauses. The supplied cache invalidator
* is used to remove deleted records from the cache.
*
* @return the number of rows deleted by this action.
*
* @throws DatabaseException if any problem is encountered communicating with the database.
*/
public int delete (CacheInvalidator invalidator)
{
requireNotNull(_where, "Where clause must be specified for delete.");
requireNull(_join, "Join clause not supported by delete.");
requireNull(_orderBy, "OrderBy clause not applicable for delete.");
requireNull(_groupBy, "GroupBy clause not applicable for delete.");
requireNull(_limit, "Limit clause not supported by delete.");
requireNull(_fromOverride, "FromOverride clause not applicable for delete.");
requireNull(_forUpdate, "ForUpdate clause not supported by delete.");
return _repo.deleteAll(_pclass, _where, invalidator);
}
protected List<QueryClause> getClauses ()
{
List<QueryClause> clauses = Lists.newArrayList();
@@ -274,6 +328,20 @@ public class QueryBuilder<T extends PersistentRecord>
}
}
protected void requireNotNull (Object value, String message)
{
if (value == null) {
throw new AssertionError(message);
}
}
protected void requireNull (Object value, String message)
{
if (value != null) {
throw new AssertionError(message);
}
}
protected final DepotRepository _repo;
protected final Class<T> _pclass;