Migrate to S4 Classes

Change-Id: I27e9452e9d59f6b414898390074908ec0e91e2a9
diff --git a/R/KorAPConnection.R b/R/KorAPConnection.R
index 85b12e4..84aec06 100644
--- a/R/KorAPConnection.R
+++ b/R/KorAPConnection.R
@@ -1,28 +1,63 @@
-#' @import jsonlite
-#' @import curl
-#' @import utils
-
-defaultKorAPUrl <- "https://korap.ids-mannheim.de/"
-
-#' Connect to a KorAP server.
+#' Class KorAPConnection
 #'
-#' @param KorAPUrl instead of providing the query and vc string parameters, you can also simply copy a KorAP query URL from your browser and use it here (and in \code{KorAPConnection}) to provide all necessary information for the query.
-#' @param apiVersion which version of KorAP's API you want to connect to
-#' @param apiUrl url of the KorAP web service
-#' @return object that contains all connection information and can be used with \code{\link{KorAPQuery}}
+#' \code{KorAPConnection} objetcs represent the connection to a KorAP server.
+#' New \code{KorAPConnection} objects can be created by \code{KorAPConnection()}
+#'
+#' @import jsonlite
+#' @import utils
+#' @import methods
+#'
+#'
+
+#' @export
+KorAPConnection <- setClass("KorAPConnection", slots=c(KorAPUrl="character", apiVersion="character", apiUrl="character"))
+
+#' @param .Object KorAPConnection object
+#' @param KorAPUrl the URL of the KorAP server instance you want to access.
+#' @param apiVersion which version of KorAP's API you want to connect to.
+#' @param apiUrl URL of the KorAP web service.
+#' @return \code{\link{KorAPConnection}} object that can be used e.g. with \code{\link{corpusQuery}}
+#'
+#' @examples
+#' kcon <- new("KorAPConnection")
+#' kq <- corpusQuery(kcon, "Ameisenplage")
+#' kq <- fetchAll(kq, verbose=TRUE)
 #'
 #' @note Currently it is not possible to authenticate the client
 #'
+#' @rdname KorAPConnection-class
 #' @export
-KorAPConnection <- function(KorAPUrl=defaultKorAPUrl, apiVersion='v1.0', apiUrl) {
-  m <-regexpr("https?://[^?]+", KorAPUrl, perl = TRUE)
-  KorAPUrl <- regmatches(KorAPUrl, m)
-  if (!endsWith(KorAPUrl, '/')) {
-    KorAPUrl <- paste0(KorAPUrl, "/")
-  }
-  if (missing(apiUrl)) {
-    apiUrl = paste0(KorAPUrl, 'api/', apiVersion, '/')
-  }
-  con <- data.frame(apiUrl, KorAPUrl, apiVersion)
-  return(con)
-}
+setMethod("initialize", "KorAPConnection",
+          function(.Object, KorAPUrl = "https://korap.ids-mannheim.de/", apiVersion = 'v1.0', apiUrl) {
+            .Object <- callNextMethod()
+            m <- regexpr("https?://[^?]+", KorAPUrl, perl = TRUE)
+            .Object@KorAPUrl <- regmatches(KorAPUrl, m)
+            if (!endsWith(.Object@KorAPUrl, '/')) {
+              .Object@KorAPUrl <- paste0(.Object@KorAPUrl, "/")
+            }
+            if (missing(apiUrl)) {
+              .Object@apiUrl = paste0(.Object@KorAPUrl, 'api/', apiVersion, '/')
+            } else {
+              .Object@apiUrl = apiUrl
+            }
+            .Object@apiVersion = apiVersion
+            .Object
+          })
+
+#' @rdname KorAPConnection-class
+#' @param object KorAPConnection object
+#' @export
+setMethod("show", "KorAPConnection", function(object) {
+  cat("<KorAPConnection>", "\n")
+  cat("apiUrl: ", object@apiUrl, "\n")
+})
+
+#' Funtion KorAPConnection()
+#'
+#' Wrappper function for new("KorAPConnection")
+#'
+#' @rdname KorAPConnection-constructor
+#' @name KorAPConnection-constructor
+#' @export
+# KorAPConnection <- function(...) new("KorAPConnection", ...)
+
diff --git a/R/KorAPCorpusStats.R b/R/KorAPCorpusStats.R
index fb30b5d..dc60133 100644
--- a/R/KorAPCorpusStats.R
+++ b/R/KorAPCorpusStats.R
@@ -1,21 +1,50 @@
-#' @import jsonlite
-#' @import curl
+#' Class KorAPCorpusStats
+#'
+#' \code{KorAPCorpusStats} objetcs can hold information about a corpus or virtual corpus.
+#' \code{KorAPCorpusStats} objects can be obtained by the \code{\link{corpusStats}()} method.
+#'
+#' @include KorAPConnection.R
+#'
+#' @export
+#' @slot vc definition of the virtual corpus
+#' @slot tokens number of tokens
+#' @slot documents number of documents
+#' @slot sentences number of sentences
+#' @slot paragraphs number of paragraphs
+setClass("KorAPCorpusStats", slots=c(vc="character", documents="numeric", tokens="numeric", sentences="numeric", paragraphs="numeric"))
 
-dummy <- NA # without this roxygen2 fails
+setGeneric("corpusStats", function(kco, ...)  standardGeneric("corpusStats") )
 
 #' Fetch information about a (virtual) corpus
-#' @param con object obtained from \code{\link{KorAPConnection}}
-#' @param query object returned from \code{\link{KorAPQuery}}
+#' @param kco \code{\link{KorAPConnection}} object (obtained e.g. from \code{new("KorAPConnection")}
 #' @param vc string describing the virtual corpus. An empty string (default) means the whole corpus, as far as it is license-wise accessible.
+#' @return \code{KorAPCorpusStats} object with the slots \code{documents}, \code{tokens}, \code{sentences}, \code{paragraphs}
+#'
+#' @examples
+#' corpusStats(new("KorAPConnection"))
+#'
+#' kco <- new("KorAPConnection")
+#' corpusStats(kco, "pubDate in 2017 & articleType=/Zeitung.*/")
+#'
+#' @aliases corpusStats
 #' @export
-#' @return object with the fields \code{$documents}, \code{$tokens}, \code{$sentences}, \code{$paragraphs}
-KorAPCorpusStats <- function(con, vc, query) {
-  if ((missing(query) && missing(vc)) || !(missing(query) || missing(vc))) {
-    stop("Exaclty one of the parameters query and vc must be specified.")
+setMethod("corpusStats", "KorAPConnection",  function(kco, vc="") {
+  url <- paste0(kco@apiUrl, 'statistics?cq=', URLencode(vc, reserved=TRUE))
+  res <- fromJSON(url)
+  new("KorAPCorpusStats", vc = vc, documents = res$documents, tokens = res$tokens, sentences = res$sentences, paragraphs = res$paragraphs)
+})
+
+#' @rdname KorAPCorpusStats-class
+#' @param object KorAPCorpusStats object
+#' @export
+setMethod("show", "KorAPCorpusStats", function(object) {
+  cat("<KorAPCorpusStats>", "\n")
+  if (object@vc == "") {
+    cat("The whole corpus")
+  } else {
+    cat("The virtual corpus described by \"", object@vc, "\"", sep="")
   }
-  if (missing(vc)) {
-    vc = query$vc
-  }
-  url <- paste0(con$apiUrl, 'statistics?cq=', URLencode(vc, reserved=TRUE))
-  return(fromJSON(url))
-}
+  cat(" contains", formatC(object@tokens, format="f", digits=0, big.mark=","), "tokens in",
+      formatC(object@sentences, format="d", big.mark=","), "sentences in",
+      formatC(object@documents, format="d", big.mark=","), "documents.\n")
+})
diff --git a/R/KorAPQuery.R b/R/KorAPQuery.R
index 1d36e8d..c02b87b 100644
--- a/R/KorAPQuery.R
+++ b/R/KorAPQuery.R
@@ -1,13 +1,67 @@
+#' Class KorAPQuery
+#'
+#' \code{KorAPQuery} objetcs represent the current state of a query to a KorAP server.
+#' New \code{KorAPQuery} objects are typically created by the \code{\link{corpusQuery}} method.
+#'
+#' @include KorAPConnection.R
 #' @import jsonlite
-#' @import curl
-#' @import utils
+#' @import httr
+#'
+#'
 
-defaultFields <- c("corpusSigle", "textSigle", "pubDate",  "pubPlace",
-            "availability", "textClass", "snippet")
+#' @export
+KorAPQuery <- setClass("KorAPQuery", slots = c(
+  "request",
+  "vc",
+  "totalResults",
+  "nextStartIndex",
+  "fields",
+  "requestUrl",
+  "webUIRequestUrl",
+  "apiResponse",
+  "collectedMatches",
+  "hasMoreMatches"
+))
 
-contentFields <- c("snippet")
+#' Method initialize
+#'
+#' @rdname KorAPQuery-class
+#' @param .Object …
+#' @param request query part of the request URL
+#' @param vc definition of a virtual corpus
+#' @param totalResults number of hits the query has yielded
+#' @param nextStartIndex at what index to start the next fetch of query results
+#' @param fields what data / metadata fields should be collected
+#' @param requestUrl complete URL of the API request
+#' @param webUIRequestUrl URL of a web frontend request corresponding to the API request
+#' @param apiResponse data-frame representation of the JSON response of the API request
+#' @param hasMoreMatches boolean that signals if more query results can be fetched
+#' @param collectedMatches matches already fetched from the KorAP-API-server
+#' @export
+setMethod("initialize", "KorAPQuery",
+          function(.Object, request = NULL, vc="", totalResults=0, nextStartIndex=0, fields=c("corpusSigle", "textSigle", "pubDate",  "pubPlace",
+                                                                              "availability", "textClass", "snippet"),
+                   requestUrl="", webUIRequestUrl = "", apiResponse = NULL, hasMoreMatches= FALSE, collectedMatches = NULL) {
+            .Object <- callNextMethod()
+            .Object@request = request
+            .Object@vc = vc
+            .Object@totalResults = totalResults
+            .Object@nextStartIndex = nextStartIndex
+            .Object@fields = fields
+            .Object@requestUrl = requestUrl
+            .Object@webUIRequestUrl = webUIRequestUrl
+            .Object@apiResponse = apiResponse
+            .Object@hasMoreMatches = hasMoreMatches
+            .Object@collectedMatches = collectedMatches
+            .Object
+          })
 
-maxResultsPerPage <- 50;
+setGeneric("corpusQuery", function(kco, ...)  standardGeneric("corpusQuery") )
+setGeneric("fetchAll", function(kqo, ...)  standardGeneric("fetchAll") )
+setGeneric("fetchNext", function(kqo, ...)  standardGeneric("fetchNext") )
+setGeneric("fetchRest", function(kqo, ...)  standardGeneric("fetchRest") )
+
+maxResultsPerPage <- 50
 
 QueryParameterFromUrl <- function(url, parameter) {
   regex <- paste0(".*[?&]", parameter, "=([^&]*).*")
@@ -22,8 +76,11 @@
   return(URLdecode(gsub(".*[?&]q=([^&]*).*", '\\1', KorAPUrl, perl = TRUE)))
 }
 
-#' Send a query to a KorAP connection.
-#' @param con object obtained from \code{\link{KorAPConnection}}, that contains all necessary connection information
+#' Method corpusQuery
+#'
+#' Perform a corpus query via a connection to a KorAP-API-server.
+#'
+#' @param kco \code{\link{KorAPConnection}} object (obtained e.g. from \code{new("KorAPConnection")}
 #' @param query string that contains the corpus query. The query langauge depends on the \code{ql} parameter. Either \code{query} must be provided or \code{KorAPUrl}
 #' @param vc string describing the virtual corpus in which the query should be performed. An empty string (default) means the whole corpus, as far as it is license-wise accessible.
 #' @param KorAPUrl instead of providing the query and vc string parameters, you can also simply copy a KorAP query URL from your browser and use it here (and in \code{KorAPConnection}) to provide all necessary information for the query.
@@ -32,99 +89,106 @@
 #' @param fields (meta)data fields that will be fetched for every match
 #' @param accessRewriteFatal abort if query or given vc had to be rewritten due to insufficent rights (not yet implemented)
 #' @param verbose print some info
-#' @return A KorAP query object that, among other information, contains the total number of results in \code{$meta$totalResults}. The resulting object can be used to fetch all query results (with \code{\link{KorAPFetchAll}}) or the next page of results (with \code{\link{KorAPFetchNext}}).
-#' A correspunding URL to be used within a web browser is contained in \code{$webUIRequestUrl}
+#' @return A \code{\link{KorAPQuery}} object that, among other information, contains the total number of results in \code{@totalResults}. The resulting object can be used to fetch all query results (with \code{\link{fetchAll}}) or the next page of results (with \code{\link{fetchNext}}).
+#' A corresponding URL to be used within a web browser is contained in \code{@webUIRequestUrl}
 #' Please make sure to check \code{$collection$rewrites} to see if any unforseen access rewrites of the query's virtual corpus had to be performed.
 #'
 #' @examples
-#' con <- KorAPConnection()
-#' q <- KorAPQuery(con, "Ameisenplage")
-#' q <- KorAPFetchAll(q)
-#' summary(q$collectedMatches)
+#' kco <- new("KorAPConnection")
+#' kqo <- corpusQuery(kco, "Ameisenplage")
+#' kqo <- fetchAll(kqo)
+#' kqo
 #'
-#' q <- KorAPQuery(con,
+#' kqo <- corpusQuery(kco,
 #'        KorAPUrl = "https://korap.ids-mannheim.de/?q=Ameise&cq=pubDate+since+2017&ql=poliqarp")
-#' q$meta$totalResults
+#' kqo
 #'
-#' q <- KorAPQuery(con, "Ameisenplage")
-#' q <- KorAPFetchAll(q, verbose=TRUE)
-#' tokensPerYear <- function(year) { return(KorAPCorpusStats(con, paste("pubDate in", year))$tokens) }
-#' df <- as.data.frame(table(as.numeric(format(q$collectedMatches$pubDate,"%Y")), dnn="year"),
+#' q <- corpusQuery(kco, "Ameisenplage")
+#' q <- fetchAll(q, verbose=TRUE)
+#' tokensPerYear <- function(year) { return(corpusStats(kco, paste("pubDate in", year))@tokens) }
+#' df <- as.data.frame(table(as.numeric(format(q@collectedMatches$pubDate,"%Y")), dnn="year"),
 #'                     stringsAsFactors = FALSE)
 #' df$ipm <- 1000000 * df$Freq / tokensPerYear(df$year)
 #' plot(df$year, df$ipm, type="l")
 #'
-#' @seealso \code{\link{KorAPConnection}}, \code{\link{KorAPFetchNext}}, \code{\link{KorAPFetchRest}}, \code{\link{KorAPFetchAll}}, \code{\link{KorAPCorpusStats}}
+#' @seealso \code{\link{KorAPConnection}}, \code{\link{fetchNext}}, \code{\link{fetchRest}}, \code{\link{fetchAll}}, \code{\link{corpusStats}}
 #'
 #' @references
 #' \url{https://ids-pub.bsz-bw.de/frontdoor/index/index/docId/9026}
 #'
+#' @aliases corpusQuery
 #' @export
-KorAPQuery <- function(con, query, vc="", KorAPUrl, metadataOnly = TRUE, ql = "poliqarp", fields = defaultFields,
-                       accessRewriteFatal = TRUE, verbose=FALSE) {
-  if (missing(query) && missing(KorAPUrl) ||  ! (missing(query) || missing(KorAPUrl))) {
-    stop("Exactly one of the parameters query and KorAPUrl must be specified.")
-  }
-  if (missing(query)) {
-    query <- QueryParameterFromUrl(KorAPUrl, "q")
-    vc <- QueryParameterFromUrl(KorAPUrl, "vc")
-    ql <- QueryParameterFromUrl(KorAPUrl, "ql")
-  }
-  request <- paste0('?q=', URLencode(query, reserved=TRUE),
-                    ifelse(vc != '', paste0('&cq=', URLencode(vc, reserved=TRUE)), ''), '&ql=', ql)
-  webUIRequestUrl <- paste0(con$KorAPUrl, request)
-  requestUrl <- paste0(con$apiUrl, 'search', request,
-                       '&fields=', paste(defaultFields, collapse = ","),
-                       ifelse(metadataOnly, '&access-rewrite-disabled=true', ''))
-  if (verbose) {
-    cat(paste0(webUIRequestUrl, "\n"))
-  }
-  result <- fromJSON(paste0(requestUrl, '&count=1'))
-  result$fields <- fields[!fields %in% contentFields]
-  result$requestUrl <- requestUrl
-  result$request <- request
-  result$vc <- vc
-  result$webUIRequestUrl <- webUIRequestUrl
-  result$nextStartIndex <- 0
-  result$hasMoreMatches <- (result$meta$totalResults > 0)
-  return(result)
-}
+setMethod("corpusQuery", "KorAPConnection",
+          function(kco, query, vc="", KorAPUrl, metadataOnly = TRUE, ql = "poliqarp", fields = defaultFields,
+                   accessRewriteFatal = TRUE, verbose=FALSE) {
+            defaultFields <- c("corpusSigle", "textSigle", "pubDate",  "pubPlace",
+                               "availability", "textClass", "snippet")
+            contentFields <- c("snippet")
+
+            if (missing(query) && missing(KorAPUrl) ||  ! (missing(query) || missing(KorAPUrl))) {
+              stop("Exactly one of the parameters query and KorAPUrl must be specified.")
+            }
+            if (missing(query)) {
+              query <- QueryParameterFromUrl(KorAPUrl, "q")
+              vc <- QueryParameterFromUrl(KorAPUrl, "vc")
+              ql <- QueryParameterFromUrl(KorAPUrl, "ql")
+            }
+            request <- paste0('?q=', URLencode(query, reserved=TRUE),
+                              ifelse(vc != '', paste0('&cq=', URLencode(vc, reserved=TRUE)), ''), '&ql=', ql)
+            webUIRequestUrl <- paste0(kco@KorAPUrl, request)
+            requestUrl <- paste0(kco@apiUrl, 'search', request,
+                                 '&fields=', paste(defaultFields, collapse = ","),
+                                 ifelse(metadataOnly, '&access-rewrite-disabled=true', ''))
+            if (verbose) {
+              cat(paste0(webUIRequestUrl, "\n"))
+            }
+            res = fromJSON(paste0(requestUrl, '&count=1'))
+            KorAPQuery(
+              nextStartIndex = 0,
+              fields = fields[!fields %in% contentFields],
+              requestUrl = requestUrl,
+              request = request,
+              totalResults = res$meta$totalResults,
+              vc = vc,
+              apiResponse = res,
+              webUIRequestUrl = webUIRequestUrl,
+              hasMoreMatches = (res$meta$totalResults > 0),
+            )
+          })
 
 #' Fetch the next bunch of results of a KorAP query.
-#' @param queryObject object obtained from \code{\link{KorAPQuery}}
+#'
+#' @param kqo object obtained from \code{\link{corpusQuery}}
 #' @param offset start offset for query results to fetch
 #' @param maxFetch maximum number of query results to fetch
 #' @param verbose print progress information if true
-#' @return The \code{queryObject} input parameter with updated fields \code{$collectedMatches}, \code{$matches} (latest bunch only), \code{$nextStartIndex}, , \code{$hasMoreMatches}
-#'
-#' @examples
-#' q <- KorAPFetchNext(KorAPQuery(KorAPConnection(), "Ameisenplage"))
-#'
-#' @seealso \code{\link{KorAPFetchRest}}, \code{\link{KorAPFetchAll}}
+#' @return The \code{kqo} input object with updated slots \code{collectedMatches}, \code{apiResponse}, \code{nextStartIndex}, \code{hasMoreMatches}
 #'
 #' @references
 #' \url{https://ids-pub.bsz-bw.de/frontdoor/index/index/docId/9026}
 #'
+#' @aliases fetchNext
+#' @rdname KorAPQuery-class
 #' @export
-KorAPFetchNext <- function(queryObject, offset = queryObject$nextStartIndex, maxFetch = maxResultsPerPage, verbose = FALSE) {
-  if (queryObject$meta$totalResults == 0 || offset >= queryObject$meta$totalResults) {
-    return(queryObject)
+setMethod("fetchNext", "KorAPQuery", function(kqo, offset = kqo@nextStartIndex, maxFetch = maxResultsPerPage, verbose = FALSE) {
+  if (kqo@totalResults == 0 || offset >= kqo@totalResults) {
+    return(kqo)
   }
 
   page <- 1
   results <- 0
   pubDate <- NULL # https://stackoverflow.com/questions/8096313/no-visible-binding-for-global-variable-note-in-r-cmd-check
-  collectedMatches <- queryObject$collectedMatches
+  collectedMatches <- kqo@collectedMatches
 
   repeat {
-    res <- fromJSON(paste0(queryObject$requestUrl, '&count=', min(ifelse(!is.na(maxFetch), maxFetch - results, maxResultsPerPage), maxResultsPerPage) ,'&offset=', offset + results))
-    if (res$meta$totalResults == 0) { return(data.frame()) }
-    for (field in queryObject$fields) {
+    res <- fromJSON(paste0(kqo@requestUrl, '&count=', min(ifelse(!is.na(maxFetch), maxFetch - results, maxResultsPerPage), maxResultsPerPage) ,'&offset=', offset + results))
+    if (res$meta$totalResults == 0) { return(kqo) }
+    for (field in kqo@fields) {
       if (!field %in% colnames(res$matches)) {
         res$matches[, field] <- NA
       }
     }
-    currentMatches <- res$matches[queryObject$fields]
+    currentMatches <- res$matches[kqo@fields]
     factorCols <- colnames(subset(currentMatches, select=-c(pubDate)))
     currentMatches[factorCols] <- lapply(currentMatches[factorCols], factor)
     currentMatches$pubDate = as.Date(currentMatches$pubDate, format = "%Y-%m-%d")
@@ -142,50 +206,72 @@
       break
     }
   }
-  res$nextStartIndex <- res$meta$startIndex + res$meta$itemsPerPage
-  res$fields <- queryObject$fields
-  res$requestUrl <- queryObject$requestUrl
-  res$request <- queryObject$request
-  res$webUIRequestUrl <- queryObject$webUIRequestUrl
-  res$hasMoreMatches <- (res$meta$totalResults > res$nextStartIndex)
-  res$collectedMatches <- collectedMatches
-  return(res)
-}
+  nextStartIndex <- min(res$meta$startIndex + res$meta$itemsPerPage, res$meta$totalResults)
+  KorAPQuery(nextStartIndex = nextStartIndex,
+    fields = kqo@fields,
+    requestUrl = kqo@requestUrl,
+    request = kqo@request,
+    totalResults = res$meta$totalResults,
+    vc = kqo@vc,
+    webUIRequestUrl = kqo@webUIRequestUrl,
+    hasMoreMatches = (res$meta$totalResults > nextStartIndex),
+    apiResponse = res,
+    collectedMatches = collectedMatches)
+})
 
 #' Fetch all results of a KorAP query.
-#' @param queryObject object obtained from \code{\link{KorAPQuery}}
-#' @param verbose print progress information if true
-#' @return The \code{queryObject} input parameter with updated fields \code{$collectedMatches}, \code{$matches} (latest bunch only), \code{$nextStartIndex}, \code{$hasMoreMatches}
 #'
 #' @examples
-#' q <- KorAPFetchAll(KorAPQuery(KorAPConnection(), "Ameisenplage"))
-#' q$collectedMatches
+#' q <- fetchAll(corpusQuery(new("KorAPConnection"), "Ameisenplage"))
+#' q@collectedMatches
 #'
-#' @seealso \code{\link{KorAPFetchRest}}, \code{\link{KorAPFetchNext}}
-#'
-#' @references
-#' \url{https://ids-pub.bsz-bw.de/frontdoor/index/index/docId/9026}
-#'
+#' @aliases fetchAll
+#' @rdname KorAPQuery-class
 #' @export
-KorAPFetchAll <- function(queryObject, verbose = FALSE) {
-  return(KorAPFetchNext(queryObject, offset = 0, maxFetch = NA, verbose = verbose))
+setMethod("fetchAll", "KorAPQuery", function(kqo, verbose = FALSE) {
+  return(fetchNext(kqo, offset = 0, maxFetch = NA, verbose = verbose))
+})
+
+#' Fetches the remaining results of a KorAP query.
+#'
+#' @examples
+#' q <- fetchRest(fetchNext(corpusQuery(new("KorAPConnection"), "Ameisenplage")))
+#' q@collectedMatches
+#'
+#' @aliases fetchRest
+#' @rdname KorAPQuery-class
+#' @export
+setMethod("fetchRest", "KorAPQuery", function(kqo, verbose = FALSE) {
+  return(fetchNext(kqo, maxFetch = NA, verbose = verbose))
+})
+
+#´ format()
+#' @rdname KorAPQuery-class
+#' @param x KorAPQuery object
+#' @param ... further arguments passed to or from other methods
+#' @export
+format.KorAPQuery <- function(x, ...) {
+  cat("<KorAPQuery>\n")
+  q <- x
+  aurl = parse_url(q@request)
+  cat("         Query: ", aurl$query$q, "\n")
+  if (!is.null(aurl$query$vc) && aurl$query$vc != "") {
+    cat("Virtual corpus: ", aurl$query$vc, "\n")
+  }
+  if (!is.null(q@collectedMatches)) {
+    cat("==============================================================================================================", "\n")
+    print(summary(q@collectedMatches))
+    cat("==============================================================================================================", "\n")
+  }
+  cat("   Total results: ", q@totalResults, "\n")
+  cat(" Fetched results: ", q@nextStartIndex, "\n")
 }
 
-#' Fetches all remaining results of a KorAP query.
-#' @param queryObject object obtained from \code{\link{KorAPQuery}}
-#' @param verbose print progress information if true
-#' @return The \code{queryObject} input parameter with updated fields \code{$collectedMatches}, \code{$matches} (latest bunch only), \code{$nextStartIndex}, \code{$hasMoreMatches}
+#' show()
 #'
-#' @examples
-#' q <- KorAPFetchRest(KorAPFetchNext(KorAPQuery(KorAPConnection(), "Ameisenplage")))
-#' q$collectedMatches
-#'
-#' @seealso \code{\link{KorAPFetchAll}}, \code{\link{KorAPFetchNext}}
-#'
-#' @references
-#' \url{https://ids-pub.bsz-bw.de/frontdoor/index/index/docId/9026}
-#'
+#' @rdname KorAPQuery-class
+#' @param object KorAPQuery object
 #' @export
-KorAPFetchRest <- function(queryObject, verbose = FALSE) {
-  return(KorAPFetchNext(queryObject, maxFetch = NA, verbose = verbose))
-}
+setMethod("show", "KorAPQuery", function(object) {
+  format(object)
+})