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A micro framework for creating web applications in Kotlin and Java 8 with minimal effort
package spark;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
/**
* This objects represent the parameters sent on a Http Request.
* Parses parameters keys like in Sinatra.
*
* For a querystring like:
* user[name]=federico&user[lastname]=dayan
*
*
* We get would get a structure like:
* user : {name: federico, lastname: dayan}
*
*
* That is:
* queryParamsMapInstance.get("user").get("name").value();
* queryParamsMapInstance.get("user").get("lastname").value();
*
* It is null safe, meaning that if a key does not exist, it does not throw NullPointerException
* , it just returns null.
*
* @author fddayan
*/
public class QueryParamsMap {
private static final QueryParamsMap NULL = new NullQueryParamsMap();
/**
* Pattern for parsing the key of querystring
*/
private static final Pattern KEY_PATTERN = Pattern.compile("\\A[\\[\\]]*([^\\[\\]]+)\\]*");
/**
* Holds the nested keys
*/
private Map queryMap = new HashMap<>();
/**
* Value(s) for this key
*/
private String[] values;
/**
* Creates a new QueryParamsMap from and HttpServletRequest.
* Parses the parameters from request.getParameterMap()
* No need to decode, since HttpServletRequest does it for us.
*
* @param request the servlet request
*/
public QueryParamsMap(HttpServletRequest request) {
if (request == null) {
throw new IllegalArgumentException("HttpServletRequest cannot be null.");
}
loadQueryString(request.getParameterMap());
}
// Just for testing
protected QueryParamsMap() {
}
/**
* Parses the key and creates the child QueryParamMaps
* user[info][name] creates 3 nested QueryParamMaps. For user, info and
* name.
*
* @param key The key in the formar fo key1[key2][key3] (for example:
* user[info][name]).
* @param values the values
*/
protected QueryParamsMap(String key, String... values) {
loadKeys(key, values);
}
/**
* Constructor
*
* @param params the parameters
*/
protected QueryParamsMap(Map params) {
loadQueryString(params);
}
/**
* loads query string
*
* @param params the parameters
*/
protected final void loadQueryString(Map params) {
for (Map.Entry param : params.entrySet()) {
loadKeys(param.getKey(), param.getValue());
}
}
/**
* loads keys
*
* @param key the key
* @param value the values
*/
protected final void loadKeys(String key, String[] value) {
String[] parsed = parseKey(key);
if (parsed == null) {
return;
}
if (!queryMap.containsKey(parsed[0])) {
queryMap.put(parsed[0], new QueryParamsMap());
}
if (!parsed[1].isEmpty()) {
queryMap.get(parsed[0]).loadKeys(parsed[1], value);
} else {
queryMap.get(parsed[0]).values = value.clone();
}
}
protected final String[] parseKey(String key) {
Matcher m = KEY_PATTERN.matcher(key);
if (m.find()) {
return new String[] {cleanKey(m.group()), key.substring(m.end())};
} else {
return null; // NOSONAR
}
}
protected static final String cleanKey(String group) {
if (group.startsWith("[")) {
return group.substring(1, group.length() - 1);
} else {
return group;
}
}
/**
* Returns an element from the specified key.
* For querystring:
*
* user[name]=fede
*
*
* get("user").get("name").value() # fede
*
* or
*
* get("user","name").value() # fede
*
* @param keys The parameter nested key(s)
* @return the query params map
*/
public QueryParamsMap get(String... keys) {
QueryParamsMap ret = this;
for (String key : keys) {
if (ret.queryMap.containsKey(key)) {
ret = ret.queryMap.get(key);
} else {
ret = NULL;
}
}
return ret;
}
/**
* Returns the value for this key.
* If this key has nested elements and does not have a value returns null.
*
* @return the value
*/
public String value() {
if (hasValue()) {
return values[0];
} else {
return null;
}
}
/**
* Returns the value for that key.
* It is a shortcut for:
*
*
* get("user").get("name").value()
* get("user").value("name")
*
*
* @param keys the key(s)
* @return the value
*/
public String value(String... keys) {
return get(keys).value();
}
/**
* @return has keys
*/
public boolean hasKeys() {
return !this.queryMap.isEmpty();
}
/**
* @return true if the map contains the given key
*/
public boolean hasKey(String key) {
return this.queryMap.containsKey( key );
}
/**
* @return has values
*/
public boolean hasValue() {
return this.values != null && this.values.length > 0;
}
/**
* @return the boolean value
*/
public Boolean booleanValue() {
return hasValue() ? Boolean.valueOf(value()) : null;
}
/**
* @return the integer value
*/
public Integer integerValue() {
return hasValue() ? Integer.valueOf(value()) : null;
}
/**
* @return the long value
*/
public Long longValue() {
return hasValue() ? Long.valueOf(value()) : null;
}
/**
* @return the float value
*/
public Float floatValue() {
return hasValue() ? Float.valueOf(value()) : null;
}
/**
* @return the double value
*/
public Double doubleValue() {
return hasValue() ? Double.valueOf(value()) : null;
}
/**
* @return the values
*/
public String[] values() {
return this.values.clone();
}
/**
* @return the queryMap
*/
Map getQueryMap() {
return queryMap;
}
/**
* @return the values
*/
String[] getValues() {
return values;
}
private static class NullQueryParamsMap extends QueryParamsMap {
public NullQueryParamsMap() {
super();
}
}
/**
* @return Map representation
*/
public Map toMap() {
Map map = new HashMap<>();
for (Entry key : this.queryMap.entrySet()) {
map.put(key.getKey(), key.getValue().values);
}
return map;
}
}