| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.openjpa.persistence.query; |
| |
| import java.util.Calendar; |
| import java.util.Date; |
| import java.util.LinkedList; |
| |
| public class CaseExpressionImpl implements CaseExpression, Visitable { |
| private LinkedList<WhenClause> _whens = new LinkedList<WhenClause>(); |
| private final Object _caseOperand; |
| |
| public CaseExpressionImpl() { |
| this(null); |
| } |
| |
| public CaseExpressionImpl(Object caseOperand) { |
| _caseOperand = caseOperand; |
| } |
| |
| public Expression elseCase(Expression arg) { |
| return new ElseExpression(this, arg); |
| } |
| |
| public Expression elseCase(String arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public Expression elseCase(Number arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public Expression elseCase(Date arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public Expression elseCase(Calendar arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public Expression elseCase(Class arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public Expression elseCase(Enum<?> arg) { |
| return new ElseExpression(this, new ConstantExpression(arg)); |
| } |
| |
| public CaseExpression then(Expression then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(Number then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(String then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(Date then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(Calendar then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(Class then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression then(Enum<?> then) { |
| assertThenState(); |
| _whens.getLast().setThen(then); |
| return this; |
| } |
| |
| public CaseExpression when(Predicate when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Expression when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Number when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(String when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Date when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Calendar when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Class when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| public CaseExpression when(Enum<?> when) { |
| assertWhenState(); |
| WhenClause clause = new WhenClause(when); |
| _whens.add(clause); |
| return this; |
| } |
| |
| void assertWhenState() { |
| boolean ok = _whens.isEmpty() || _whens.getLast().hasThen(); |
| if (!ok) |
| throw new IllegalStateException("when() can not be called now"); |
| } |
| |
| void assertThenState() { |
| boolean ok = !_whens.isEmpty() && !_whens.getLast().hasThen(); |
| if (!ok) |
| throw new IllegalStateException("then() can not be called now"); |
| } |
| |
| public String asExpression(AliasContext ctx) { |
| StringBuilder tmp = new StringBuilder("CASE "); |
| if (_caseOperand != null) { |
| tmp.append(toJPQL(ctx, _caseOperand)); |
| } |
| for (WhenClause when : _whens) { |
| tmp.append(when.toJPQL(ctx)); |
| } |
| return tmp.toString(); |
| } |
| |
| public String asProjection(AliasContext ctx) { |
| return asExpression(ctx); |
| } |
| |
| public String asJoinable(AliasContext ctx) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public String getAliasHint(AliasContext ctx) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| |
| |
| String toJPQL(AliasContext ctx, Object o) { |
| if (o instanceof Visitable) { |
| return ((Visitable)o).asExpression(ctx); |
| } |
| return o.toString(); |
| } |
| } |