01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: *
17: */
18:
19: package org.apache.tools.ant.taskdefs.condition;
20:
21: import org.apache.tools.ant.BuildException;
22:
23: /**
24: * <not> condition.
25: *
26: * Evaluates to true if the single condition nested into it is false
27: * and vice versa.
28: *
29: * @since Ant 1.4
30: */
31: public class Not extends ConditionBase implements Condition {
32:
33: /**
34: * Evaluate condition
35: *
36: * @return true if the condition is true.
37: * @throws BuildException if the condition is not configured correctly.
38: */
39: public boolean eval() throws BuildException {
40: if (countConditions() > 1) {
41: throw new BuildException("You must not nest more than one "
42: + "condition into <not>");
43: }
44: if (countConditions() < 1) {
45: throw new BuildException(
46: "You must nest a condition into <not>");
47: }
48: return !((Condition) getConditions().nextElement()).eval();
49: }
50:
51: }
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