ibdo :: get parameter as string

src/main/java/emissary/core/BaseDataObject.java

@@ -27,6 +27,7 @@
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -994,32 +995,61 @@ public boolean appendUniqueParameter(final String key, final CharSequence value)
     }
 
     @Override
+    @Deprecated
     public String getStringParameter(final String key) {
-        return getStringParameter(key, DEFAULT_PARAM_SEPARATOR);
+        return getParameterAsConcatString(key);
     }
 
     @Nullable
     @Override
+    @Deprecated
     public String getStringParameter(final String key, final String sep) {
+        return getParameterAsConcatString(key, sep);
+    }
+
+    @Override
+    public Collection<String> getParameterAsStrings(final String key) {
         final List<Object> obj = getParameter(key);
+
         if (obj == null) {
-            return null;
+            return Collections.emptyList();
         } else if (obj.isEmpty()) {
-            return null;
+            return Collections.emptyList();
         } else if ((obj.size() == 1) && (obj.get(0) instanceof String)) {
-            return (String) obj.get(0);
+            return Collections.singletonList((String) obj.get(0));
         } else if ((obj.size() == 1) && (obj.get(0) == null)) {
-            return null;
+            return Collections.emptyList();
         } else {
-            final StringBuilder sb = new StringBuilder();
+            final List<String> values = new ArrayList<>(obj.size());
             for (final Object item : obj) {
-                if (sb.length() > 0) {
-                    sb.append(sep);
-                }
-                sb.append(item);
+                values.add(String.valueOf(item));
             }
-            return sb.toString();
+            return Collections.unmodifiableList(values);
+        }
+    }
+
+    @Nullable
+    @Override
+    public String getParameterAsString(final String key) {
+        final Collection<String> paramStrings = getParameterAsStrings(key);
+        if (paramStrings.size() > 1) {
+            throw new IllegalStateException("There is more than one value for parameter[" + key + " ]!!");
         }
+
+        return StringUtils.trimToNull(paramStrings.stream().findFirst().orElse(null));
+    }
+
+    @Nullable
+    @Override
+    public String getParameterAsConcatString(final String key) {
+        return getStringParameter(key, DEFAULT_PARAM_SEPARATOR);
+    }
+
+    @Nullable
+    @Override
+    public String getParameterAsConcatString(final String key, final String sep) {
+        final String strParameter = String.join(sep, getParameterAsStrings(key));
+        return StringUtils.isBlank(strParameter) ? null : strParameter;
     }
 
     /**

src/main/java/emissary/core/IBaseDataObject.java

@@ -350,7 +350,9 @@ enum MergePolicy {
      * 
      * @param key name of the metadata element
      * @return the string value or null if no such element
+     * @deprecated use {@link #getParameterAsConcatString(String)}
      */
+    @Deprecated
     String getStringParameter(String key);
 
     /**
@@ -359,9 +361,46 @@ enum MergePolicy {
      * @param key name of the metadata element
      * @param sep the separator for multivalued fields
      * @return the string value or null if no such element
+     * @deprecated use {@link #getParameterAsConcatString(String, String)}
      */
+    @Deprecated
     String getStringParameter(String key, String sep);
 
+    /**
+     * Retrieve the Collection of metadata values identified by key where each element is converted to a string
+     *
+     * @param key name of the metadata element collection
+     * @return Collection of elements converted to strings
+     */
+    Collection<String> getParameterAsStrings(String key);
+
+    /**
+     * Retrieve the metadata value identified by key where the element is converted to a string
+     *
+     * @param key name of the metadata element
+     * @return parameter converted to strings
+     * @throws IllegalStateException if the parameter has more than one value
+     */
+    String getParameterAsString(String key);
+
+
+    /**
+     * Retrieve a specified metadata element as a string of concatenated values
+     *
+     * @param key name of the metadata element
+     * @return the string value or null if no such element
+     */
+    String getParameterAsConcatString(String key);
+
+    /**
+     * Retrieve a specified metadata element as a string of concatenated values
+     *
+     * @param key name of the metadata element
+     * @param sep the separator for multivalued fields
+     * @return the string value or null if no such element
+     */
+    String getParameterAsConcatString(String key, String sep);
+
     /**
      * Retrieve all the metadata elements of this object
      *