Service Layer changes for Recommission API

server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttribute.java

@@ -0,0 +1,92 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * {@link DecommissionAttribute} encapsulates information about decommissioned node attribute like attribute name, attribute value.
+ *
+ * @opensearch.internal
+ */
+public final class DecommissionAttribute implements Writeable {
+    private final String attributeName;
+    private final String attributeValue;
+
+    /**
+     * Constructs new decommission attribute name value pair
+     *
+     * @param attributeName   attribute name
+     * @param attributeValue attribute value
+     */
+    public DecommissionAttribute(String attributeName, String attributeValue) {
+        this.attributeName = attributeName;
+        this.attributeValue = attributeValue;
+    }
+
+    /**
+     * Returns attribute name
+     *
+     * @return attributeName
+     */
+    public String attributeName() {
+        return this.attributeName;
+    }
+
+    /**
+     * Returns attribute value
+     *
+     * @return attributeValue
+     */
+    public String attributeValue() {
+        return this.attributeValue;
+    }
+
+    public DecommissionAttribute(StreamInput in) throws IOException {
+        attributeName = in.readString();
+        attributeValue = in.readString();
+    }
+
+    /**
+     * Writes decommission attribute name value to stream output
+     *
+     * @param out stream output
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(attributeName);
+        out.writeString(attributeValue);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        DecommissionAttribute that = (DecommissionAttribute) o;
+
+        if (!attributeName.equals(that.attributeName)) return false;
+        return attributeValue.equals(that.attributeValue);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributeName, attributeValue);
+    }
+
+    @Override
+    public String toString() {
+        return "DecommissionAttribute{" + "attributeName='" + attributeName + '\'' + ", attributeValue='" + attributeValue + '\'' + '}';
+    }
+}

server/src/main/java/org/opensearch/cluster/decommission/DecommissionFailedException.java

@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown whenever a failure occurs in decommission request @{@link DecommissionService}
+ *
+ * @opensearch.internal
+ */
+public class DecommissionFailedException extends OpenSearchException {
+
+    private final DecommissionAttribute decommissionAttribute;
+
+    public DecommissionFailedException(DecommissionAttribute decommissionAttribute, String msg) {
+        this(decommissionAttribute, msg, null);
+    }
+
+    public DecommissionFailedException(DecommissionAttribute decommissionAttribute, String msg, Throwable cause) {
+        super("[" + (decommissionAttribute == null ? "_na" : decommissionAttribute.toString()) + "] " + msg, cause);
+        this.decommissionAttribute = decommissionAttribute;
+    }
+
+    public DecommissionFailedException(StreamInput in) throws IOException {
+        super(in);
+        decommissionAttribute = new DecommissionAttribute(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        decommissionAttribute.writeTo(out);
+    }
+
+    /**
+     * Returns decommission attribute
+     *
+     * @return decommission attribute
+     */
+    public DecommissionAttribute decommissionAttribute() {
+        return decommissionAttribute;
+    }
+}