Added CharacterCodec for encoding and decoding from and to a Character.

Added CharacterCodec to ValueCodecProvider.

 JAVA-1804

Author: jyemin

bson/src/main/org/bson/codecs/CharacterCodec.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2015 MongoDB, Inc.
+ *
+ * Licensed 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.bson.codecs;
+
+import org.bson.BsonInvalidOperationException;
+import org.bson.BsonReader;
+import org.bson.BsonWriter;
+
+import static java.lang.String.format;
+import static org.bson.assertions.Assertions.notNull;
+
+/**
+ * Encodes and decodes {@code Character} objects.
+ *
+ * @since 3.0
+ */
+public class CharacterCodec implements Codec<Character> {
+    @Override
+    public void encode(final BsonWriter writer, final Character value, final EncoderContext encoderContext) {
+        notNull("value", value);
+
+        writer.writeString(value.toString());
+    }
+
+    @Override
+    public Character decode(final BsonReader reader, final DecoderContext decoderContext) {
+        String string = reader.readString();
+        if (string.length() != 1) {
+            throw new BsonInvalidOperationException(format("Attempting to decode the string '%s' to a character, but its length is not "
+                                                           + "equal to one", string));
+        }
+
+        return string.charAt(0);
+    }
+
+    @Override
+    public Class<Character> getEncoderClass() {
+        return Character.class;
+    }
+}

bson/src/main/org/bson/codecs/ValueCodecProvider.java

@@ -37,6 +37,7 @@
  *     <li>{@link org.bson.codecs.MaxKeyCodec}</li>
  *     <li>{@link org.bson.codecs.CodeCodec}</li>
  *     <li>{@link org.bson.codecs.ObjectIdCodec}</li>
+ *     <li>{@link org.bson.codecs.CharacterCodec}</li>
  *     <li>{@link org.bson.codecs.StringCodec}</li>
  *     <li>{@link org.bson.codecs.SymbolCodec}</li>
  *     <li>{@link org.bson.codecs.UuidCodec}</li>
@@ -78,6 +79,7 @@ private void addCodecs() {
         addCodec(new MaxKeyCodec());
         addCodec(new CodeCodec());
         addCodec(new ObjectIdCodec());
+        addCodec(new CharacterCodec());
         addCodec(new StringCodec());
         addCodec(new SymbolCodec());
         addCodec(new UuidCodec());

bson/src/test/unit/org/bson/codecs/CharacterCodecSpecification.groovy

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2015 MongoDB, Inc.
+ *
+ * Licensed 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.bson.codecs
+
+import org.bson.BsonDocument
+import org.bson.BsonDocumentReader
+import org.bson.BsonDocumentWriter
+import org.bson.BsonInvalidOperationException
+import org.bson.BsonString
+import spock.lang.Specification
+
+class CharacterCodecSpecification extends Specification {
+    private final CharacterCodec codec = new CharacterCodec()
+
+    def 'should get encoder class'() {
+        expect:
+        codec.encoderClass == Character
+    }
+    def 'when encoding a character, should throw if it is null'() {
+        given:
+        def writer = new BsonDocumentWriter(new BsonDocument())
+
+        when:
+        codec.encode(writer, null, EncoderContext.builder().build())
+
+        then:
+        thrown(IllegalArgumentException)
+    }
+
+    def 'should encode a character'() {
+        given:
+        def writer = new BsonDocumentWriter(new BsonDocument())
+
+        when:
+        writer.writeStartDocument()
+        writer.writeName('str')
+        codec.encode(writer, 'c' as char, EncoderContext.builder().build())
+        writer.writeEndDocument()
+
+        then:
+        writer.document == new BsonDocument('str', new BsonString('c'))
+    }
+
+    def 'should decode a character'() {
+        given:
+        def reader = new BsonDocumentReader(new BsonDocument('str', new BsonString('c')))
+
+        when:
+        reader.readStartDocument()
+        reader.readName()
+        def character = codec.decode(reader, DecoderContext.builder().build())
+
+        then:
+        character == 'c' as char
+    }
+
+    def 'when decoding a string whose length is not 1, should throw a BsonInvalidOperationException'() {
+        given:
+        def reader = new BsonDocumentReader(new BsonDocument('str', new BsonString('cc')))
+
+        when:
+        reader.readStartDocument()
+        reader.readName()
+        codec.decode(reader, DecoderContext.builder().build())
+
+        then:
+        thrown(BsonInvalidOperationException)
+    }
+}

bson/src/test/unit/org/bson/codecs/ValueCodecProviderSpecification.groovy

@@ -45,6 +45,7 @@ class ValueCodecProviderSpecification extends Specification {
         provider.get(Integer, registry) instanceof IntegerCodec
         provider.get(Long, registry) instanceof LongCodec
         provider.get(Double, registry) instanceof DoubleCodec
+        provider.get(Character, registry) instanceof CharacterCodec
         provider.get(String, registry) instanceof StringCodec
         provider.get(Date, registry) instanceof DateCodec
         provider.get(Byte, registry) instanceof ByteCodec
@@ -64,4 +65,4 @@ class ValueCodecProviderSpecification extends Specification {
         provider.get(Document, registry) == null
     }
 
-}
+}