public void setMatchingETagConstraints(List<String> eTagList) {
        this.matchingETagConstraints = eTagList;
    }
Sets the optional list of ETag constraints that when present <b>must</b>
include a match for the object's current ETag in order for this
request to be executed. If none of the specified ETags match the object's
current ETag, this request will not be executed. Only one ETag in the
list needs to match for the request to be executed by Amazon S3.

@param eTagList
           The optional list of ETag constraints that <b>must</b> include a
           match for the object's current ETag in order for this request
           to be executed.

@see GetObjectRequest#getMatchingETagConstraints()
@see GetObjectRequest#withMatchingETagConstraint(String)
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/model/GetObjectRequest.java