01: /**
02: * MVEL (The MVFLEX Expression Language)
03: *
04: * Copyright (C) 2007 Christopher Brock, MVFLEX/Valhalla Project and the Codehaus
05: *
06: * Licensed under the Apache License, Version 2.0 (the "License");
07: * you may not use this file except in compliance with the License.
08: * You may obtain a copy of the License at
09: *
10: * http://www.apache.org/licenses/LICENSE-2.0
11: *
12: * Unless required by applicable law or agreed to in writing, software
13: * distributed under the License is distributed on an "AS IS" BASIS,
14: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15: * See the License for the specific language governing permissions and
16: * limitations under the License.
17: *
18: */package org.mvel.compiler;
19:
20: import static org.mvel.util.PropertyTools.isNumeric;
21:
22: import java.io.Serializable;
23: import static java.lang.String.valueOf;
24: import java.util.Collection;
25:
26: public class BlankLiteral implements Serializable {
27: public static final BlankLiteral INSTANCE = new BlankLiteral();
28:
29: public BlankLiteral() {
30: }
31:
32: public boolean equals(Object obj) {
33: if (obj == null || "".equals(valueOf(obj))) {
34: return true;
35: } else if (isNumeric(obj)) {
36: return "0".equals(valueOf(obj));
37: } else if (obj instanceof Collection) {
38: return ((Collection) obj).size() == 0;
39: } else if (obj.getClass().isArray()) {
40: return ((Object[]) obj).length == 0;
41: }
42: return false;
43: }
44:
45: public String toString() {
46: return "";
47: }
48: }
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