<p>
return the value of data-* attribute. If not set, return null.
</p>

@param key
data-"key"
@return null if not found attribute
542855
public String getData(String key) {
        QName qn = new QName("data-" + key);
        return this.getOtherAttributes().get(qn);
    }
737746
public Data get(Key key) {
		synchronized (cache) {
			Pair<Data,Long> p = cache.get(key);
			if (p != null) {
				p.setValue2(Long.valueOf(System.currentTimeMillis()));
				return p.getValue1();
			}
			p = new Pair<>(provider.provide(key), Long.valueOf(System.currentTimeMillis()));
			cache.put(key, p);
			return p.getValue1();
		}
	}
831332
public String getValue(String key) throws Exception{

    Object val = null;

    for (ObjectName oname: hadoopObjectNames) {
      try {
        val = mbsc.getAttribute(oname, key);
      } catch (AttributeNotFoundException anfe) {
        /*just go to the next */
        continue;
      } catch(ReflectionException re) {
        if (re.getCause() instanceof NoSuchMethodException) {
          continue;
        }
      }
      err("Info: key = " + key + "; val = " + val);
      break;
    }

    return (val == null) ? null : val.toString();
  }
26338
public Property get(String key) {
        for (Property property : properties) {
            if (property.getKey().equals(key)) {
                return property;
            }
        }
        return null;
    }
742188
public synchronized XAttribute get(Object key) {
		if(backingStore != null) {
			return backingStore.get(key);
		} else {
			return null;
		}
	}
845724
private String getAttributeKeyValue(String key) {
    String prefix = key + '=';
    String attribute = getAttribute(prefix);
    return attribute != null ? attribute.substring(prefix.length()) : null;
  }
385168
public Object value(int i, String key) {
        Object data = getData();
        if (data instanceof List) {
            List list = (List) data;
            if (list.size() > 0) {
                Map map = (Map) list.get(i);
                return map.get(key);
            }
        } else if (data instanceof Map) {
            return ((Map) data).get(key);
        }
        return null;
    }
838188
public Object getFirstValue(String key) {
    List values = fields.get(key);
    return values.size() > 0 ? values.get(0) : null;
  }
71763
@Override
    public Object getValue(@NonNull String key) {
        if (key == null) { throw new IllegalArgumentException("key cannot be null."); }

        final int index = indexForColumnName(key);
        return index >= 0 ? getValue(index) : null;
    }
729126
public String get(String key) {
        Objects.requireNonNull(key, Required.KEY.toString());

        return this.values.get(key);
    }
669182
public Property getProperty(String key) {
        for (Property property : m_properties) {
            if (property.getKey().equals(key)) {
                return property;
            }
        }
        
        return null;
    }
469399
public <T> T getAttribute(String key, Class<T> clazz) {
        return (T) getAttribute(key);
    }
485755
public String get(String key) {
        int i = indexOfKey(key);
        return i == NotFound ? EmptyString : checkNotNull(vals[i]);
    }
748215
public Object get(String key) {
    if (!StringUtil.isEmpty(key)) {
      if (pendingInstanceData.containsKey(key)) {
        return pendingInstanceData.get(key);
      }
      if (instanceData.containsKey(key)) {
        return instanceData.get(key);
      }
    }
    return null;
  }
1344687
public Object attribute(Object key) {
        return (attributes != null) ? attributes.get(key) : null;
    }
1302275
public String get(final String key) {
        final Collection<Argument> args = map.get(key);
        if (args != null) {
            return args.iterator().hasNext() ? args.iterator().next().getValue() : null;
        }
        return null;
    }
494458
public Object getAttribute(String key) {
    Object value;
    if (pendingAttributes.containsKey(key)) {
      value = pendingAttributes.get(key);
    } else {
      value = attributes.get(key);
    }
    return value;
  }