org.xillium.data.DataBinder Maven / Gradle / Ivy
package org.xillium.data;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.io.*;
import java.util.*;
import java.sql.*;
import org.xillium.base.beans.Beans;
import org.xillium.base.beans.Strings;
import org.xillium.base.beans.JSONBuilder;
import org.xillium.base.util.Multimap;
import org.xillium.data.persistence.ResultSetWorker;
/**
* A data binder
*/
public class DataBinder extends HashMap implements ResultSetWorker {
/**
* The recommended name for a "response" DataBinder when placed within another DataBinder.
*
* @see #DataBinder(DataBinder, String)
*/
public static final String RESPONSE = "[RESPONSE]";
private final Map _rsets = new HashMap();
private final Map _named = new HashMap();
private final DataBinder _lower;
/**
* Creates a standalone DataBinder.
*/
public DataBinder() {
_lower = null;
}
/**
* Creates a DataBinder that sits on top of another binder.
*
* @param binder an existing binder
*/
public DataBinder(DataBinder binder) {
_lower = binder;
}
/**
* Creates a DataBinder that sits on top of and at the same time is placed as a named object inside another binder.
*
* @param binder an existing binder
* @param name the name of this new binder inside the existing binder
*/
public DataBinder(DataBinder binder, String name) {
_lower = binder;
binder.putNamedObject(name, this);
}
public DataBinder getLower() {
return _lower;
}
/**
* Finds a string value from all data binders, starting from the current binder searching downwards.
*
* @param name the name of the value
* @return the first value found
*/
public String find(String name) {
String value = null;
for (DataBinder top = this; top != null && (value = top.get(name)) == null; top = top.getLower());
return value;
}
/**
* Puts a new string value into this binder, but using an alternative value if the given one is null.
*/
public String put(String name, String value, String alternative) {
return put(name, value != null ? value : alternative);
}
/**
* Puts a new result set into this binder.
*/
public CachedResultSet putResultSet(String name, CachedResultSet rs) {
return _rsets.put(name, rs);
}
/**
* Retrieves a result set from this binder.
*/
public CachedResultSet getResultSet(String name) {
return _rsets.get(name);
}
/**
* Retrieves the set of all result set names.
*/
public Set getResultSetNames() {
return _rsets.keySet();
}
/**
* Puts a named object into this binder returning the original object under the name, if any.
*/
@SuppressWarnings("unchecked")
public T putNamedObject(String name, V object) {
return (T)_named.put(name, object);
}
/**
* Retrieves a named object from this binder.
*/
@SuppressWarnings("unchecked")
public T getNamedObject(String name) {
return (T)_named.get(name);
}
/**
* Retrieves a named object of a specific type from this binder.
*/
public T getNamedObject(String name, Class type) {
return type.cast(_named.get(name));
}
/**
* Retrieves the set of all named object names.
*/
public Set getNamedObjectNames() {
return _named.keySet();
}
/**
* Introduces a HashMap under the given name if one does not exist yet.
*/
public Map map(String name, Class ktype, Class vtype) {
Map map = getNamedObject(name);
if (map == null) putNamedObject(name, map = new HashMap());
return map;
}
/**
* Introduces a Multimap under the given name if one does not exist yet.
*/
public Multimap mul(String name, Class ktype, Class vtype) {
Multimap map = getNamedObject(name);
if (map == null) putNamedObject(name, map = new Multimap());
return map;
}
/**
* Fills the data binder with columns in the current row of a result set.
*/
@Override
public DataBinder process(ResultSet rset) throws Exception {
try {
if (rset.next()) {
ResultSetMetaData meta = rset.getMetaData();
int width = meta.getColumnCount();
for (int i = 1; i <= width; ++i) {
Object value = rset.getObject(i);
if (value != null) {
put(Strings.toLowerCamelCase(meta.getColumnLabel(i), '_'), value.toString());
}
}
} else {
throw new NoSuchElementException("NoSuchRow");
}
return this;
} finally {
rset.close();
}
}
/**
* Fills the data binder with non-static, non-transient fields of an Object, excluding null values.
*/
public DataBinder put(Object object) throws Exception {
for (Field field: Beans.getKnownInstanceFields(object.getClass())) {
Object value = field.get(object);
if (value != null) {
put(field.getName(), value.toString());
}
}
return this;
}
/**
* Fills the data binder with a subset of non-static, non-transient fields of an Object, excluding null values.
*
* @param names - the names of the fields in the subset
*/
public DataBinder put(T object, String... names) throws Exception {
Class type = object.getClass();
Object value;
for (String name: names) {
Field field = Beans.getKnownField(type, name);
if (!Modifier.isStatic(field.getModifiers()) && !Modifier.isTransient(field.getModifiers()) && (value = field.get(object)) != null) {
put(field.getName(), value.toString());
}
}
return this;
}
/**
* Removes all auto-values (those whose names start and end with '#').
*
* @return the number of auto-values removed
*/
public int clearAutoValues() {
int count = 0;
Iterator> it = entrySet().iterator();
while (it.hasNext()) {
String key = it.next().getKey();
if (key.charAt(0) == '#' && key.charAt(key.length()-1) == '#') {
it.remove();
++count;
}
}
return count;
}
/**
* Loads parameters from an array of strings each in the form of name=value.
*/
public DataBinder load(String[] args, int offset) {
for (int i = offset; i < args.length; ++i) {
int equal = args[i].indexOf('=');
if (equal > 0) {
put(args[i].substring(0, equal), args[i].substring(equal + 1));
} else {
throw new RuntimeException("***InvalidParameter{" + args[i] + '}');
}
}
return this;
}
/**
* Loads parameters from a property file.
*/
public DataBinder load(String filename) throws IOException {
Properties props = new Properties();
Reader reader = new FileReader(filename);
props.load(reader);
reader.close();
return load(props);
}
/**
* Loads parameters from a Properties object.
*/
public DataBinder load(Properties props) {
Enumeration enumeration = props.propertyNames();
while (enumeration.hasMoreElements()) {
String key = (String)enumeration.nextElement();
put(key, props.getProperty(key));
}
return this;
}
/**
* Provides a very rough estimate of how big a JSON representative of this binder might be.
*/
public int estimateMaximumBytes() {
int count = this.size();
for (String key: _rsets.keySet()) {
CachedResultSet crs = _rsets.get(key);
if (crs.rows != null) {
count += crs.columns.length*crs.rows.size();
}
}
return count * 64;
}
/**
* Returns a JSON string representing the contents of this data binder, excluding named objects.
*/
public String toJSON() {
JSONBuilder jb = new JSONBuilder(estimateMaximumBytes()).append('{');
appendParams(jb).append(',');
appendTables(jb);
jb.append('}');
return jb.toString();
}
public JSONBuilder appendParams(JSONBuilder jb) {
boolean json = false;
jb.append("\"params\":{ ");
Iterator it = keySet().iterator();
while (it.hasNext()) {
String key = it.next();
String val = get(key);
if (val == null) {
jb.quote(key).append(":null");
} else if (val.startsWith("json:")) {
json = true;
continue;
} else {
jb.serialize(key, val);
}
jb.append(',');
}
jb.replaceLast('}');
if (json) {
jb.append(",\"values\":{ ");
it = keySet().iterator();
while (it.hasNext()) {
String key = it.next();
String val = get(key);
if (val != null && val.startsWith("json:")) {
jb.quote(key).append(':').append(val.substring(5)).append(',');
}
}
jb.replaceLast('}');
}
return jb;
}
public JSONBuilder appendTables(JSONBuilder jb) {
jb.append("\"tables\":{ ");
Set rsets = getResultSetNames();
Iterator it = rsets.iterator();
while (it.hasNext()) {
String name = it.next();
jb.quote(name).append(":");
getResultSet(name).toJSON(jb);
jb.append(',');
}
jb.replaceLast('}');
return jb;
}
/**
* A data binder decoder.
*/
public static interface Decoder {
/**
* Decodes an InputStream and collects data parameters into a DataBinder.
*
* @return the InputStream
*/
public InputStream decode(DataBinder binder, InputStream stream) throws Exception;
}
/**
* A data binder encoder.
*/
public static interface Encoder {
/**
* Returns the MIME content type of this encoder's output.
*
* @return the MIME content type
*/
public String getContentType(DataBinder binder);
/**
* Encodes a DataBinder and writes the bytes into an OutputStream.
*
* @return the OutputStream
*/
public T encode(T sink, DataBinder binder) throws Exception;
}
/**
* An object equipped with a DataBinder.Decoder.
*/
public static interface WithDecoder {
/**
* Returns a DataBinder.Decoder
*
* @return the Decoder
*/
public Decoder getDataBinderDecoder();
}
/**
* An object equipped with a DataBinder.Encoder.
*/
public static interface WithEncoder {
/**
* Returns a DataBinder.Encoder
*
* @return the Encoder.
*/
public Encoder getDataBinderEncoder();
}
private static final long serialVersionUID = -4575511652015221913L;
}
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