Added three new index alias related apis.

Added apis to get specific index aliases based on filtering by alias name and index name:
```
curl -XGET 'localhost:9200/{index_or_alias}/_alias/{alias_name}'
```

Added delete index alias api for deleting a single index alias:
```
curl -XDELETE 'localhost:9200/{index}/_alias/{alias_name}'
```

Added create index alias api for adding a single index alias:
```
curl -XPUT 'localhost:9200/{index}/_alias/{alias_name}'

curl -XPUT 'localhost:9200/{index}/_alias/{alias_name}' -d '{
	"routing" : {routing},
	"filter" : {filter}
}'

```

Closes #3075 #3076 #3077

src/main/java/org/elasticsearch/action/ActionModule.java

@@ -42,6 +42,8 @@
 import org.elasticsearch.action.admin.cluster.state.TransportClusterStateAction;
 import org.elasticsearch.action.admin.indices.alias.IndicesAliasesAction;
 import org.elasticsearch.action.admin.indices.alias.TransportIndicesAliasesAction;
+import org.elasticsearch.action.admin.indices.alias.get.IndicesGetAliasesAction;
+import org.elasticsearch.action.admin.indices.alias.get.TransportIndicesGetAliasesAction;
 import org.elasticsearch.action.admin.indices.analyze.AnalyzeAction;
 import org.elasticsearch.action.admin.indices.analyze.TransportAnalyzeAction;
 import org.elasticsearch.action.admin.indices.cache.clear.ClearIndicesCacheAction;
@@ -201,6 +203,7 @@ protected void configure() {
         registerAction(ClearIndicesCacheAction.INSTANCE, TransportClearIndicesCacheAction.class);
         registerAction(PutWarmerAction.INSTANCE, TransportPutWarmerAction.class);
         registerAction(DeleteWarmerAction.INSTANCE, TransportDeleteWarmerAction.class);
+        registerAction(IndicesGetAliasesAction.INSTANCE, TransportIndicesGetAliasesAction.class);
 
         registerAction(IndexAction.INSTANCE, TransportIndexAction.class);
         registerAction(GetAction.INSTANCE, TransportGetAction.class);

src/main/java/org/elasticsearch/action/admin/indices/alias/get/IndicesGetAliasesAction.java

@@ -0,0 +1,45 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you 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.elasticsearch.action.admin.indices.alias.get;
+
+import org.elasticsearch.action.admin.indices.IndicesAction;
+import org.elasticsearch.client.IndicesAdminClient;
+
+/**
+ */
+public class IndicesGetAliasesAction extends IndicesAction<IndicesGetAliasesRequest, IndicesGetAliasesResponse, IndicesGetAliasesRequestBuilder> {
+
+    public static final IndicesGetAliasesAction INSTANCE = new IndicesGetAliasesAction();
+    public static final String NAME = "indices/get/aliases";
+
+    private IndicesGetAliasesAction() {
+        super(NAME);
+    }
+
+    @Override
+    public IndicesGetAliasesRequestBuilder newRequestBuilder(IndicesAdminClient client) {
+        return new IndicesGetAliasesRequestBuilder(client);
+    }
+
+    @Override
+    public IndicesGetAliasesResponse newResponse() {
+        return new IndicesGetAliasesResponse();
+    }
+}

src/main/java/org/elasticsearch/action/admin/indices/alias/get/IndicesGetAliasesRequest.java

@@ -0,0 +1,103 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you 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.elasticsearch.action.admin.indices.alias.get;
+
+import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.action.support.IgnoreIndices;
+import org.elasticsearch.action.support.master.MasterNodeOperationRequest;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+import static org.elasticsearch.action.ValidateActions.addValidationError;
+
+/**
+ */
+public class IndicesGetAliasesRequest extends MasterNodeOperationRequest<IndicesGetAliasesRequest> {
+
+    private String[] indices = Strings.EMPTY_ARRAY;
+    private String[] aliases = Strings.EMPTY_ARRAY;
+
+    private IgnoreIndices ignoreIndices = IgnoreIndices.NONE;
+
+    public IndicesGetAliasesRequest(String[] aliases) {
+        this.aliases = aliases;
+    }
+
+    public IndicesGetAliasesRequest(String alias) {
+        this.aliases = new String[]{alias};
+    }
+
+    IndicesGetAliasesRequest() {
+    }
+
+    public IndicesGetAliasesRequest indices(String... indices) {
+        this.indices = indices;
+        return this;
+    }
+
+    public IndicesGetAliasesRequest aliases(String... aliases) {
+        this.aliases = aliases;
+        return this;
+    }
+
+    public IndicesGetAliasesRequest ignoreIndices(IgnoreIndices ignoreIndices) {
+        this.ignoreIndices = ignoreIndices;
+        return this;
+    }
+
+    public String[] indices() {
+        return indices;
+    }
+
+    public String[] aliases() {
+        return aliases;
+    }
+
+    public IgnoreIndices ignoreIndices() {
+        return ignoreIndices;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        if (aliases.length == 0) {
+            return addValidationError("No alias specified", null);
+        } else {
+            return null;
+        }
+    }
+
+    @Override
+    public void readFrom(StreamInput in) throws IOException {
+        super.readFrom(in);
+        indices = in.readStringArray();
+        aliases = in.readStringArray();
+        ignoreIndices = IgnoreIndices.fromId(in.readByte());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(indices);
+        out.writeStringArray(aliases);
+        out.writeByte(ignoreIndices.id());
+    }
+}

src/main/java/org/elasticsearch/action/admin/indices/alias/get/IndicesGetAliasesRequestBuilder.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you 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.elasticsearch.action.admin.indices.alias.get;
+
+import com.google.common.collect.ObjectArrays;
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.elasticsearch.client.IndicesAdminClient;
+import org.elasticsearch.client.internal.InternalIndicesAdminClient;
+
+/**
+ */
+public class IndicesGetAliasesRequestBuilder extends MasterNodeOperationRequestBuilder<IndicesGetAliasesRequest, IndicesGetAliasesResponse, IndicesGetAliasesRequestBuilder> {
+
+    public IndicesGetAliasesRequestBuilder(IndicesAdminClient client, String... aliases) {
+        super((InternalIndicesAdminClient)client, new IndicesGetAliasesRequest(aliases));
+    }
+
+    public IndicesGetAliasesRequestBuilder setAliases(String... aliases) {
+        request.aliases(aliases);
+        return this;
+    }
+
+    public IndicesGetAliasesRequestBuilder addAliases(String... aliases) {
+        request.aliases(ObjectArrays.concat(request.aliases(), aliases, String.class));
+        return this;
+    }
+
+    public IndicesGetAliasesRequestBuilder setIndices(String... indices) {
+        request.indices(indices);
+        return this;
+    }
+
+    public IndicesGetAliasesRequestBuilder addIndices(String... indices) {
+        request.indices(ObjectArrays.concat(request.indices(), indices, String.class));
+        return this;
+    }
+
+    @Override
+    protected void doExecute(ActionListener<IndicesGetAliasesResponse> listener) {
+        ((IndicesAdminClient) client).getAliases(request, listener);
+    }
+
+}

src/main/java/org/elasticsearch/action/admin/indices/alias/get/IndicesGetAliasesResponse.java

@@ -0,0 +1,78 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you 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.elasticsearch.action.admin.indices.alias.get;
+
+import org.elasticsearch.action.ActionResponse;
+import org.elasticsearch.cluster.metadata.AliasMetaData;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ */
+public class IndicesGetAliasesResponse extends ActionResponse {
+
+    private Map<String, List<AliasMetaData>> aliases = new HashMap<String, List<AliasMetaData>>();
+
+    public IndicesGetAliasesResponse(Map<String, List<AliasMetaData>> aliases) {
+        this.aliases = aliases;
+    }
+
+    IndicesGetAliasesResponse() {
+    }
+
+
+    public Map<String, List<AliasMetaData>> getAliases() {
+        return aliases;
+    }
+
+    @Override
+    public void readFrom(StreamInput in) throws IOException {
+        super.readFrom(in);
+        int size = in.readVInt();
+        for (int i = 0; i < size; i++) {
+            String key = in.readString();
+            int valueSize = in.readVInt();
+            List<AliasMetaData> value = new ArrayList<AliasMetaData>(valueSize);
+            for (int j = 0; j < valueSize; j++) {
+                value.add(AliasMetaData.Builder.readFrom(in));
+            }
+            aliases.put(key, value);
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeVInt(aliases.size());
+        for (Map.Entry<String, List<AliasMetaData>> entry : aliases.entrySet()) {
+            out.writeString(entry.getKey());
+            out.writeVInt(entry.getValue().size());
+            for (AliasMetaData aliasMetaData : entry.getValue()) {
+                AliasMetaData.Builder.writeTo(aliasMetaData, out);
+            }
+        }
+    }
+}

src/main/java/org/elasticsearch/action/admin/indices/alias/get/TransportIndicesGetAliasesAction.java

@@ -0,0 +1,77 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you 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.elasticsearch.action.admin.indices.alias.get;
+
+import org.elasticsearch.ElasticSearchException;
+import org.elasticsearch.action.support.master.TransportMasterNodeOperationAction;
+import org.elasticsearch.cluster.ClusterService;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.AliasMetaData;
+import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.indices.AliasMissingException;
+import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.transport.TransportService;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ */
+public class TransportIndicesGetAliasesAction extends TransportMasterNodeOperationAction<IndicesGetAliasesRequest, IndicesGetAliasesResponse> {
+
+    @Inject
+    public TransportIndicesGetAliasesAction(Settings settings, TransportService transportService, ClusterService clusterService, ThreadPool threadPool) {
+        super(settings, transportService, clusterService, threadPool);
+    }
+
+    @Override
+    protected String transportAction() {
+        return IndicesGetAliasesAction.NAME;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.MANAGEMENT;
+    }
+
+    @Override
+    protected IndicesGetAliasesRequest newRequest() {
+        return new IndicesGetAliasesRequest();
+    }
+
+    @Override
+    protected IndicesGetAliasesResponse newResponse() {
+        return new IndicesGetAliasesResponse();
+    }
+
+    @Override
+    protected IndicesGetAliasesResponse masterOperation(IndicesGetAliasesRequest request, ClusterState state) throws ElasticSearchException {
+        String[] concreteIndices = state.metaData().concreteIndices(request.indices(), request.ignoreIndices(), true);
+        request.indices(concreteIndices);
+
+        @SuppressWarnings("unchecked") // ImmutableList to List results incompatible type
+        Map<String, List<AliasMetaData>> result = (Map) state.metaData().findAliases(request.aliases(), request.indices());
+        if (result.isEmpty()) {
+            throw new AliasMissingException(request.aliases());
+        }
+        return new IndicesGetAliasesResponse(result);
+    }
+
+}