BuildInfoUtil.java revision 08119ea342cb47910ca80ff646d746f00e4663ce 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.databinding.annotationprocessor;
18
19import android.databinding.BindingBuildInfo;
20import android.databinding.tool.processing.ScopedException;
21import android.databinding.tool.util.L;
22import android.databinding.tool.util.Preconditions;
23
24import java.lang.annotation.Annotation;
25
26import javax.annotation.processing.RoundEnvironment;
27import javax.lang.model.element.Element;
28
29public class BuildInfoUtil {
30    private static BindingBuildInfo sCached;
31    public static BindingBuildInfo load(RoundEnvironment roundEnvironment) {
32        if (sCached == null) {
33            sCached = extractNotNull(roundEnvironment, BindingBuildInfo.class);
34            if (sCached != null) {
35                L.setDebugLog(sCached.enableDebugLogs());
36                ScopedException.encodeOutput(sCached.printEncodedError());
37            }
38        }
39        return sCached;
40    }
41
42    private static <T extends Annotation> T extractNotNull(RoundEnvironment roundEnv,
43            Class<T> annotationClass) {
44        T result = null;
45        for (Element element : roundEnv.getElementsAnnotatedWith(annotationClass)) {
46            final T info = element.getAnnotation(annotationClass);
47            if (info == null) {
48                continue; // It gets confused between BindingAppInfo and BinderBundle
49            }
50            Preconditions.check(result == null, "Should have only one %s",
51                    annotationClass.getCanonicalName());
52            result = info;
53        }
54        return result;
55    }
56}
57