/**
* Perform a standard browse, which will return a BrowseInfo object that represents the results
* for the current page, the total number of results, the range, and information to construct
* previous and next links on any web page
*
* @param bs the scope of the browse
* @return the results of the browse
* @throws BrowseException
*/
public BrowseInfo browse(BrowserScope bs) throws BrowseException {
log.debug(LogManager.getHeader(context, "browse", ""));
// first, load the browse scope into the object
this.scope = bs;
// since we use it so much, get the browse index out of the
// scope and store as a member
browseIndex = scope.getBrowseIndex();
// now make the decision as to how to browse
if (browseIndex.isMetadataIndex() && !scope.isSecondLevel()) {
// this is a single value browse type that has not gone to
// the second level (i.e. authors, not items by a given author)
return browseByValue(scope);
} else {
// this is the full browse type or a browse that has gone to
// the second level
return browseByItem(scope);
}
}
/**
* Browse the archive by the full item browse mechanism. This produces a BrowseInfo object which
* contains full BrowseItem objects as its result set.
*
* @param bs the scope of the browse
* @return the results of the browse
* @throws BrowseException
*/
private BrowseInfo browseByItem(BrowserScope bs) throws BrowseException {
log.info(LogManager.getHeader(context, "browse_by_item", ""));
try {
// get the table name that we are going to be getting our data from
dao.setTable(browseIndex.getTableName());
// tell the browse query whether we are ascending or descending on the value
dao.setAscending(scope.isAscending());
// assemble the value clause
String rawValue = null;
if (scope.hasFilterValue() && scope.isSecondLevel()) {
String value = scope.getFilterValue();
rawValue = value;
// make sure the incoming value is normalised
value =
OrderFormat.makeSortString(
value, scope.getFilterValueLang(), scope.getBrowseIndex().getDataType());
dao.setAuthorityValue(scope.getAuthorityValue());
// set the values in the Browse Query
if (scope.isSecondLevel()) {
dao.setFilterValueField("value");
dao.setFilterValue(rawValue);
} else {
dao.setFilterValueField("sort_value");
dao.setFilterValue(value);
}
dao.setFilterValuePartial(scope.getFilterValuePartial());
// to apply the filtering, we need the distinct and map tables for the index
dao.setFilterMappingTables(
browseIndex.getDistinctTableName(), browseIndex.getMapTableName());
}
// define a clause for the WHERE clause which will allow us to constrain
// our browse to a specified community or collection
if (scope.inCollection() || scope.inCommunity()) {
if (scope.inCollection()) {
Collection col = (Collection) scope.getBrowseContainer();
dao.setContainerTable("collection2item");
dao.setContainerIDField("collection_id");
dao.setContainerID(col.getID());
} else if (scope.inCommunity()) {
Community com = (Community) scope.getBrowseContainer();
dao.setContainerTable("communities2item");
dao.setContainerIDField("community_id");
dao.setContainerID(com.getID());
}
}
// this is the total number of results in answer to the query
int total = getTotalResults();
// assemble the ORDER BY clause
String orderBy = browseIndex.getSortField(scope.isSecondLevel());
if (scope.getSortBy() > 0) {
orderBy = "sort_" + Integer.toString(scope.getSortBy());
}
dao.setOrderField(orderBy);
int offset = scope.getOffset();
String rawFocusValue = null;
if (offset < 1
&& (scope.hasJumpToItem() || scope.hasJumpToValue() || scope.hasStartsWith())) {
// We need to convert these to an offset for the actual browse query.
// First, get a value that we can look up in the ordering field
rawFocusValue = getJumpToValue();
// make sure the incoming value is normalised
String focusValue = normalizeJumpToValue(rawFocusValue);
log.debug("browsing using focus: " + focusValue);
// Convert the focus value into an offset
offset = getOffsetForValue(focusValue);
}
dao.setOffset(offset);
// assemble the LIMIT clause
dao.setLimit(scope.getResultsPerPage());
// Holder for the results
List<BrowseItem> results = null;
// Does this browse have any contents?
if (total > 0) {
// now run the query
results = dao.doQuery();
// now, if we don't have any results, we are at the end of the browse. This will
// be because a starts_with value has been supplied for which we don't have
// any items.
if (results.size() == 0) {
// In this case, we will calculate a new offset for the last page of results
offset = total - scope.getResultsPerPage();
if (offset < 0) {
offset = 0;
}
// And rerun the query
dao.setOffset(offset);
results = dao.doQuery();
}
} else {
// No records, so make an empty list
results = new ArrayList<BrowseItem>();
}
// construct the BrowseInfo object to pass back
// BrowseInfo browseInfo = new BrowseInfo(results, position, total, offset);
BrowseInfo browseInfo = new BrowseInfo(results, offset, total, offset);
if (offset + scope.getResultsPerPage() < total) {
browseInfo.setNextOffset(offset + scope.getResultsPerPage());
}
if (offset - scope.getResultsPerPage() > -1) {
browseInfo.setPrevOffset(offset - scope.getResultsPerPage());
}
// add the browse index to the Browse Info
browseInfo.setBrowseIndex(browseIndex);
// set the sort option for the Browse Info
browseInfo.setSortOption(scope.getSortOption());
// tell the Browse Info which way we are sorting
browseInfo.setAscending(scope.isAscending());
// tell the Browse Info which level of browse we are at
browseInfo.setBrowseLevel(scope.getBrowseLevel());
// set the browse value if there is one
browseInfo.setValue(rawValue);
// set the browse authority key if there is one
browseInfo.setAuthority(scope.getAuthorityValue());
// set the focus value if there is one
browseInfo.setFocus(rawFocusValue);
if (scope.hasJumpToItem()) {
browseInfo.setFocusItem(scope.getJumpToItem());
}
// tell the browse info if it is working from a starts with parameter
browseInfo.setStartsWith(scope.hasStartsWith());
// tell the browse info what the container for the browse was
if (scope.inCollection() || scope.inCommunity()) {
browseInfo.setBrowseContainer(scope.getBrowseContainer());
}
browseInfo.setResultsPerPage(scope.getResultsPerPage());
browseInfo.setEtAl(scope.getEtAl());
return browseInfo;
} catch (SQLException e) {
log.error("caught exception: ", e);
throw new BrowseException(e);
}
}
/**
* Perform a limited browse, which only returns the results requested, without any extraneous
* information. To perform a full browse, use BrowseEngine.browse() above. This supports Item
* browse only, and does not currently support focus or values. This method is used, for example,
* to generate the Recently Submitted Items results.
*
* @param bs the scope of the browse
* @return the results of the browse
*/
public BrowseInfo browseMini(BrowserScope bs) throws BrowseException {
log.info(LogManager.getHeader(context, "browse_mini", ""));
// load the scope into the object
this.scope = bs;
// since we use it so much, get the browse index out of the
// scope and store as a member
browseIndex = scope.getBrowseIndex();
// get the table name that we are going to be getting our data from
dao.setTable(browseIndex.getTableName());
// tell the browse query whether we are ascending or descending on the value
dao.setAscending(scope.isAscending());
// define a clause for the WHERE clause which will allow us to constrain
// our browse to a specified community or collection
if (scope.inCollection() || scope.inCommunity()) {
if (scope.inCollection()) {
Collection col = (Collection) scope.getBrowseContainer();
dao.setContainerTable("collection2item");
dao.setContainerIDField("collection_id");
dao.setContainerID(col.getID());
} else if (scope.inCommunity()) {
Community com = (Community) scope.getBrowseContainer();
dao.setContainerTable("communities2item");
dao.setContainerIDField("community_id");
dao.setContainerID(com.getID());
}
}
dao.setOffset(scope.getOffset());
dao.setLimit(scope.getResultsPerPage());
// assemble the ORDER BY clause
String orderBy = browseIndex.getSortField(scope.isSecondLevel());
if (scope.getSortBy() > 0) {
orderBy = "sort_" + Integer.toString(scope.getSortBy());
}
dao.setOrderField(orderBy);
// now run the query
List<BrowseItem> results = dao.doQuery();
// construct the mostly empty BrowseInfo object to pass back
BrowseInfo browseInfo = new BrowseInfo(results, 0, scope.getResultsPerPage(), 0);
// add the browse index to the Browse Info
browseInfo.setBrowseIndex(browseIndex);
// set the sort option for the Browse Info
browseInfo.setSortOption(scope.getSortOption());
// tell the Browse Info which way we are sorting
browseInfo.setAscending(scope.isAscending());
// tell the browse info what the container for the browse was
if (scope.inCollection() || scope.inCommunity()) {
browseInfo.setBrowseContainer(scope.getBrowseContainer());
}
browseInfo.setResultsPerPage(scope.getResultsPerPage());
browseInfo.setEtAl(scope.getEtAl());
return browseInfo;
}