Add nullability annotations to improve Kotlin support

Builder methods taking objects are maked with @nonnull. It doesn't make
sense to provide 'null' rather than not calling them. Some DataSource
constructor parameters can be null though.

Author: saschpe

exoplayer2-ext-icy/src/main/java/saschpe/exoplayer2/ext/icy/IcyHttpDataSource.java

@@ -1,5 +1,7 @@
 package saschpe.exoplayer2.ext.icy;
 
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.util.Log;
 
 import com.google.android.exoplayer2.upstream.DataSource;
@@ -47,13 +49,13 @@ public interface IcyMetadataListener {
     }
 
     private IcyHttpDataSource(
-            final String userAgent,
-            final Predicate<String> contentTypePredicate,
-            final TransferListener<? super DefaultHttpDataSource> listener,
+            @NonNull final String userAgent,
+            @Nullable final Predicate<String> contentTypePredicate,
+            @Nullable final TransferListener<? super DefaultHttpDataSource> listener,
             final int connectTimeoutMillis,
             final int readTimeoutMillis,
             final boolean allowCrossProtocolRedirects,
-            final RequestProperties defaultRequestProperties) {
+            @Nullable final RequestProperties defaultRequestProperties) {
         super(userAgent, contentTypePredicate, listener, connectTimeoutMillis, readTimeoutMillis, allowCrossProtocolRedirects, defaultRequestProperties);
         defaultRequestProperties.set(REQUEST_HEADER_ICY_METAINT_KEY, REQUEST_HEADER_ICY_METAINT_VALUE);
         // See class Builder
@@ -210,16 +212,16 @@ public final static class Builder {
         private IcyHeadersListener icyHeadersListener;
         private IcyMetadataListener icyMetadataListener;
 
-        public Builder(final String userAgent) {
+        public Builder(@NonNull final String userAgent) {
             this.userAgent = userAgent;
         }
 
-        public Builder setContentTypePredicate(final Predicate<String> contentTypePredicate) {
+        public Builder setContentTypePredicate(@NonNull final Predicate<String> contentTypePredicate) {
             this.contentTypePredicate = contentTypePredicate;
             return this;
         }
 
-        public Builder setTransferListener(final TransferListener<? super DataSource> listener) {
+        public Builder setTransferListener(@NonNull final TransferListener<? super DataSource> listener) {
             this.listener = listener;
             return this;
         }
@@ -239,17 +241,17 @@ public Builder setAllowCrossProtocolRedirects(final boolean allowCrossProtocolRe
             return this;
         }
 
-        public Builder setDefaultRequestProperties(final RequestProperties defaultRequestProperties) {
+        public Builder setDefaultRequestProperties(@NonNull final RequestProperties defaultRequestProperties) {
             this.defaultRequestProperties = defaultRequestProperties;
             return this;
         }
 
-        public Builder setIcyHeadersListener(final IcyHttpDataSource.IcyHeadersListener icyHeadersListener) {
+        public Builder setIcyHeadersListener(@NonNull final IcyHttpDataSource.IcyHeadersListener icyHeadersListener) {
             this.icyHeadersListener = icyHeadersListener;
             return this;
         }
 
-        public Builder setIcyMetadataListener(final IcyMetadataListener icyMetadataListener) {
+        public Builder setIcyMetadataListener(@NonNull final IcyMetadataListener icyMetadataListener) {
             this.icyMetadataListener = icyMetadataListener;
             return this;
         }

exoplayer2-ext-icy/src/main/java/saschpe/exoplayer2/ext/icy/IcyHttpDataSourceFactory.java

@@ -1,5 +1,7 @@
 package saschpe.exoplayer2.ext.icy;
 
+import android.support.annotation.NonNull;
+
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
@@ -32,7 +34,7 @@ public final static class Builder {
          *
          * @param userAgent The user agent
          */
-        public Builder(final String userAgent) {
+        public Builder(@NonNull final String userAgent) {
             // Apply defaults
             factory = new IcyHttpDataSourceFactory();
             factory.userAgent = userAgent;
@@ -42,32 +44,32 @@ public Builder(final String userAgent) {
             factory.allowCrossProtocolRedirects = false;
         }
 
-        public Builder setTransferListener(final TransferListener<? super DataSource> listener) {
+        public Builder setTransferListener(@NonNull final TransferListener<? super DataSource> listener) {
             factory.listener = listener;
             return this;
         }
 
-        public Builder setConnectTimeoutMillis(final int connectTimeoutMillis) {
+        public Builder setConnectTimeoutMillis(@NonNull final int connectTimeoutMillis) {
             factory.connectTimeoutMillis = connectTimeoutMillis;
             return this;
         }
 
-        public Builder setReadTimeoutMillis(final int readTimeoutMillis) {
+        public Builder setReadTimeoutMillis(@NonNull final int readTimeoutMillis) {
             factory.readTimeoutMillis = readTimeoutMillis;
             return this;
         }
 
-        public Builder setAllowCrossProtocolRedirects(final boolean allowCrossProtocolRedirects) {
+        public Builder setAllowCrossProtocolRedirects(@NonNull final boolean allowCrossProtocolRedirects) {
             factory.allowCrossProtocolRedirects = allowCrossProtocolRedirects;
             return this;
         }
 
-        public Builder setIcyHeadersListener(final IcyHttpDataSource.IcyHeadersListener icyHeadersListener) {
+        public Builder setIcyHeadersListener(@NonNull final IcyHttpDataSource.IcyHeadersListener icyHeadersListener) {
             factory.icyHeadersListener = icyHeadersListener;
             return this;
         }
 
-        public Builder setIcyMetadataChangeListener(final IcyHttpDataSource.IcyMetadataListener icyMetadataListener) {
+        public Builder setIcyMetadataChangeListener(@NonNull final IcyHttpDataSource.IcyMetadataListener icyMetadataListener) {
             factory.icyMetadataListener = icyMetadataListener;
             return this;
         }
@@ -78,7 +80,7 @@ public IcyHttpDataSourceFactory build() {
     }
 
     @Override
-    protected IcyHttpDataSource createDataSourceInternal(HttpDataSource.RequestProperties defaultRequestProperties) {
+    protected IcyHttpDataSource createDataSourceInternal(@NonNull HttpDataSource.RequestProperties defaultRequestProperties) {
         return new IcyHttpDataSource.Builder(userAgent)
                 .setTransferListener(listener)
                 .setConnectTimeoutMillis(connectTimeoutMillis)