Add writing and reading of String lists to StreamIO classes

Author: cbuescher

src/main/java/org/elasticsearch/common/io/stream/StreamInput.java

@@ -335,6 +335,21 @@ public String[] readStringArray() throws IOException {
         return ret;
     }
 
+    /**
+     * Read in a list of strings. List can be empty but not {@code null}.
+     */
+    public List<String> readStringList() throws IOException {
+        int size = readVInt();
+        if (size == 0) {
+            return Collections.emptyList();
+        }
+        List<String> ret = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            ret.add(readString());
+        }
+        return ret;
+    }
+
     @Nullable
     public Map<String, Object> readMap() throws IOException {
         return (Map<String, Object>) readGenericValue();
@@ -427,7 +442,7 @@ public int[] readIntArray() throws IOException {
         }
         return values;
     }
-    
+
     public long[] readLongArray() throws IOException {
         int length = readVInt();
         long[] values = new long[length];
@@ -436,7 +451,7 @@ public long[] readLongArray() throws IOException {
         }
         return values;
     }
-    
+
     public float[] readFloatArray() throws IOException {
         int length = readVInt();
         float[] values = new float[length];
@@ -445,7 +460,7 @@ public float[] readFloatArray() throws IOException {
         }
         return values;
     }
-    
+
     public double[] readDoubleArray() throws IOException {
         int length = readVInt();
         double[] values = new double[length];

src/main/java/org/elasticsearch/common/io/stream/StreamOutput.java

@@ -283,6 +283,16 @@ public void writeStringArray(String[] array) throws IOException {
         }
     }
 
+    /**
+     * Write a list of strings. List can be empty but not {@code null}.
+     */
+    public void writeStringList(List<String> stringList) throws IOException {
+        writeVInt(stringList.size());
+        for (String s : stringList) {
+            writeString(s);
+        }
+    }
+
     /**
      * Writes a string array, for nullable string, writes it as 0 (empty string).
      */
@@ -399,21 +409,21 @@ public void writeIntArray(int[] value) throws IOException {
             writeInt(value[i]);
         }
     }
-    
+
     public void writeLongArray(long[] value) throws IOException {
         writeVInt(value.length);
         for (int i=0; i<value.length; i++) {
             writeLong(value[i]);
         }
     }
-    
+
     public void writeFloatArray(float[] value) throws IOException {
         writeVInt(value.length);
         for (int i=0; i<value.length; i++) {
             writeFloat(value[i]);
         }
     }
-    
+
     public void writeDoubleArray(double[] value) throws IOException {
         writeVInt(value.length);
         for (int i=0; i<value.length; i++) {

src/main/java/org/elasticsearch/index/query/IdsQueryBuilder.java

@@ -123,7 +123,7 @@ protected void doXContent(XContentBuilder builder, Params params) throws IOExcep
         builder.startObject(IdsQueryParser.NAME);
         if (types != null) {
             if (types.size() == 1) {
-                builder.field("type", types.iterator().next());
+                builder.field("type", types.get(0));
             } else {
                 builder.startArray("types");
                 for (String type : types) {
@@ -177,19 +177,18 @@ public QueryValidationException validate() {
         return null;
     }
 
-    @SuppressWarnings("unchecked")
     @Override
     public void readFrom(StreamInput in) throws IOException {
-        this.types = (List<String>) in.readGenericValue();
-        this.ids = (List<String>) in.readGenericValue();
+        this.types = in.readStringList();
+        this.ids = in.readStringList();
         queryName = in.readOptionalString();
         boost = in.readFloat();
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeGenericValue(this.types);
-        out.writeGenericValue(this.ids);
+        out.writeStringList(this.types);
+        out.writeStringList(this.ids);
         out.writeOptionalString(queryName);
         out.writeFloat(boost);
     }