fix TranslateProcessorConfig to load target.type property correct (Fix#5961) (#5969)

**What?**

This commit update TranslateProcessorConfig to load the target.type property
from pipeline config with Jackson's support. The cause is that converter parameter
is not updated while Jackson parsing the target.type properly. The fix removes
the unncessary private field converter and instead return targetType.

It also make secondar contstructor protected for unit test only.

**Why?**

Make target.type property in translate processor to take effect.

Signed-off-by: Wenjie Yao <wjyao@amazon.com>
Co-authored-by: Wenjie Yao <wjyao@amazon.com>

Author: wjyao0316

data-prepper-plugins/translate-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/translate/TargetsParameterConfig.java

@@ -9,6 +9,7 @@
 import org.opensearch.dataprepper.model.annotations.AlsoRequired;
 import org.opensearch.dataprepper.plugins.processor.mutateevent.TargetType;
 import org.opensearch.dataprepper.typeconverter.TypeConverter;
+import com.google.common.annotations.VisibleForTesting;
 
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -21,7 +22,6 @@
 public class TargetsParameterConfig {
     static final String MAP_KEY = "map";
     static final String REGEX_KEY = "regex";
-    private final TypeConverter converter;
     private final LinkedHashMap<Range<Float>, Object> rangeMappings = new LinkedHashMap<>();
     private final Map<String, Object> individualMappings = new HashMap<>();
     private final Map<Pattern, Object> compiledPatterns = new HashMap<>();
@@ -57,18 +57,17 @@ public class TargetsParameterConfig {
     @JsonPropertyDescription("Specifies the data type for the target value.")
     private TargetType targetType = TargetType.STRING;
 
-    public TargetsParameterConfig(){
-        converter = TargetType.STRING.getTargetConverter();
-    }
-    public TargetsParameterConfig(Map<String, Object> map, String target, RegexParameterConfiguration regexParameterConfig, String translateWhen, String defaultValue, TargetType targetType) {
+    public TargetsParameterConfig(){}
+
+    @VisibleForTesting
+    TargetsParameterConfig(Map<String, Object> map, String target, RegexParameterConfiguration regexParameterConfig, String translateWhen, String defaultValue, TargetType targetType) {
         this.targetType = Optional
                 .ofNullable(targetType)
                 .orElse(TargetType.STRING);
         this.target = target;
         this.map = map;
         this.defaultValue = defaultValue;
         this.regexParameterConfig = regexParameterConfig;
-        this.converter = this.targetType.getTargetConverter();
         this.translateWhen = translateWhen;
         parseMappings();
     }
@@ -109,11 +108,6 @@ public Map<Pattern, Object> fetchCompiledPatterns() {
         return compiledPatterns;
     }
 
-    public TypeConverter getConverter() {
-        return converter;
-    }
-
-
     @AssertTrue(message = "pattern option is mandatory while configuring regex option")
     public boolean isPatternPresent() {
         return regexParameterConfig == null || regexParameterConfig.getPatterns() != null;

data-prepper-plugins/translate-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/translate/TranslateProcessor.java

@@ -134,7 +134,7 @@ private String getSourceValue(Object recordObject, String sourceKey) {
     }
 
     private Object getTargetValue(Object sourceObject, List<Object> targetValues, TargetsParameterConfig targetConfig) {
-        TypeConverter converter = targetConfig.getConverter();
+        TypeConverter converter = targetConfig.getTargetType().getTargetConverter();
         if(sourceObject instanceof String) {
             return converter.convert(targetValues.get(0));
         }