[#1178] Allow for treating Condition as Field<Boolean>

jOOQ-test/src/org/jooq/test/_/testcases/PredicateTests.java

@@ -40,7 +40,6 @@ import static junit.framework.Assert.assertEquals;
 import static org.jooq.SQLDialect.ASE;
 import static org.jooq.SQLDialect.DB2;
 import static org.jooq.SQLDialect.DERBY;
-import static org.jooq.SQLDialect.MYSQL;
 import static org.jooq.conf.StatementType.STATIC_STATEMENT;
 import static org.jooq.impl.Factory.all;
 import static org.jooq.impl.Factory.any;
@@ -48,12 +47,15 @@ import static org.jooq.impl.Factory.castNull;
 import static org.jooq.impl.Factory.concat;
 import static org.jooq.impl.Factory.count;
 import static org.jooq.impl.Factory.escape;
+import static org.jooq.impl.Factory.field;
 import static org.jooq.impl.Factory.lower;
+import static org.jooq.impl.Factory.one;
 import static org.jooq.impl.Factory.select;
 import static org.jooq.impl.Factory.selectOne;
 import static org.jooq.impl.Factory.trueCondition;
 import static org.jooq.impl.Factory.upper;
 import static org.jooq.impl.Factory.val;
+import static org.jooq.impl.Factory.zero;
 
 import java.sql.Date;
 import java.util.ArrayList;
@@ -63,6 +65,7 @@ import java.util.List;
 
 import org.jooq.Condition;
 import org.jooq.Field;
+import org.jooq.Record;
 import org.jooq.Record1;
 import org.jooq.Record2;
 import org.jooq.Record3;
@@ -459,7 +462,7 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T725,
                 .fetch(TBook_ID()));
 
         // [#1073] Some dialects incorrectly handle NULL in NOT IN predicates
-        if (asList(ASE, MYSQL).contains(getDialect())) {
+        if (asList(ASE).contains(getDialect())) {
             assertEquals(
             asList(2, 3, 4),
             create().select(TBook_ID())
@@ -488,6 +491,14 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T725,
             .orderBy(TBook_ID()).fetch(TBook_ID()));
     }
 
+    @Test
+    public void testConditionsAsFields() throws Exception {
+        Record record = create().select(field(one().eq(zero())), field(one().eq(1))).fetchOne();
+
+        assertEquals(false, record.getValue(0));
+        assertEquals(true, record.getValue(1));
+    }
+
     @Test
     public void testQuantifiedPredicates() throws Exception {
 

jOOQ-test/src/org/jooq/test/jOOQAbstractTest.java

@@ -1030,6 +1030,11 @@ public abstract class jOOQAbstractTest<
         new PredicateTests(this).testConditions();
     }
 
+    @Test
+    public void testConditionsAsFields() throws Exception {
+        new PredicateTests(this).testConditionsAsFields();
+    }
+
     @Test
     public void testQuantifiedPredicates() throws Exception {
         new PredicateTests(this).testQuantifiedPredicates();

jOOQ/src/main/java/org/jooq/impl/ConditionAsField.java

@@ -0,0 +1,92 @@
+/**
+ * Copyright (c) 2009-2012, Lukas Eder, lukas.eder@gmail.com
+ * All rights reserved.
+ *
+ * This software is licensed to you under the Apache License, Version 2.0
+ * (the "License"); You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * . Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * . Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * . Neither the name "jOOQ" nor the names of its contributors may be
+ *   used to endorse or promote products derived from this software without
+ *   specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.jooq.impl;
+
+import static org.jooq.impl.Factory.inline;
+
+import org.jooq.Condition;
+import org.jooq.Configuration;
+import org.jooq.QueryPart;
+
+/**
+ * @author Lukas Eder
+ */
+class ConditionAsField extends AbstractFunction<Boolean> {
+
+    /**
+     * Generated UID
+     */
+    private static final long serialVersionUID = -5921673852489483721L;
+    private final Condition   condition;
+
+    ConditionAsField(Condition condition) {
+        super(condition.toString(), SQLDataType.BOOLEAN);
+
+        this.condition = condition;
+    }
+
+    @Override
+    final QueryPart getFunction0(Configuration configuration) {
+        switch (configuration.getDialect()) {
+
+            // Most databases don't accept predicates where column expressions
+            // are expected.
+            case CUBRID:
+            case DB2:
+            case ORACLE:
+            case SQLSERVER:
+                return Factory.decode().when(condition, inline(true)).otherwise(inline(false));
+
+            // These databases can inline predicates in column expression contexts
+            case DERBY:
+            case H2:
+            case HSQLDB:
+            case MYSQL:
+            case POSTGRES:
+            case SQLITE:
+
+            // Unknown (to be evaluated):
+            case ASE:
+            case FIREBIRD:
+            case INGRES:
+            case SYBASE:
+                return condition;
+        }
+
+        // The default, for new dialects
+        return condition;
+    }
+}

jOOQ/src/main/java/org/jooq/impl/Factory.java

@@ -3053,6 +3053,14 @@ public class Factory {
         return condition.not();
     }
 
+    /**
+     * Transform a condition into a boolean field
+     */
+    @Support
+    public static Field<Boolean> field(Condition condition) {
+        return new ConditionAsField(condition);
+    }
+
     // -------------------------------------------------------------------------
     // XXX Global Field and Function factory
     // -------------------------------------------------------------------------