How to use

validateKey

method

in

co.cask.cdap.api.metadata.MetadataEntity$Builder

/**
 * Put the given key (case insensitive) with the given value in {@link MetadataEntity.Builder}.
 * The returned {@link MetadataEntity} type is set to the given key. If an append is required without the
 * type change then {@link #append(String, String)} should be used.
 *
 * @param key the key (case insensitive) to be added
 * @param value the value to be added
 * @return a new {@link MetadataEntity.Builder} whose type is set to the given key and consists of the given
 * key and value in addition
 */
public Builder appendAsType(String key, String value) {
 validateKey(key);
 parts.put(key.toLowerCase(), value);
 this.type = key.toLowerCase();
 return this;
}

/**
 * Put the given key (case insensitive) with the given value in {@link MetadataEntity.Builder}.
 * The returned {@link MetadataEntity.Builder} is of the same type. If the type needs to
 * changed during append then {@link #appendAsType(String, String)}  should be used.
 *
 * @param key the key (case insensitive) to be added
 * @param value the value to be added
 * @return a new {@link MetadataEntity.Builder} which is of same type of this {@link MetadataEntity.Builder}
 * but consists of the given key and value in addition
 */
public Builder append(String key, String value) {
 validateKey(key);
 parts.put(key.toLowerCase(), value);
 return this;
}