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ru.shemplo.snowball.annot.processor.SnowflakeInitializer Maven / Gradle / Ivy
package ru.shemplo.snowball.annot.processor;
import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.function.Predicate;
import java.util.stream.Stream;
import ru.shemplo.snowball.annot.Snowflake;
public final class SnowflakeInitializer {
private static final Predicate NEED_REFRESH
= m -> !m.isAnnotationPresent (Snowflake.class) ? false
: m.getAnnotation (Snowflake.class).refresh ();
private final Class TOKEN;
private final Method METHOD;
private final Field FIELD;
private T instance;
private final boolean REFRESH;
private final int PRIORITY;
public SnowflakeInitializer (Class token, int priority) {
this (token, null, null, null, priority,
NEED_REFRESH.test (token));
}
public SnowflakeInitializer (Field field, int priority) {
this (null, field, null, null, priority,
NEED_REFRESH.test (field));
}
public SnowflakeInitializer (Method method, int priority) {
this (null, null, method, null, priority,
NEED_REFRESH.test (method));
}
public SnowflakeInitializer (T instance, int priority) {
this (null, null, null, instance, priority, false);
}
private SnowflakeInitializer (Class token, Field field,
Method method, T instance, int priority, boolean refresh) {
this.TOKEN = token; this.FIELD = field; this.METHOD = method;
this.instance = instance; this.PRIORITY = priority;
this.REFRESH = refresh;
}
@Override
public String toString () {
return String.format ("SI of `%s` (t: %b, f: %b, m: %b, i: %b)", getType (),
TOKEN != null, FIELD != null, METHOD != null, instance != null);
}
public Class getType () {
return TOKEN != null ? TOKEN
: (METHOD != null ? METHOD.getReturnType ()
: (FIELD != null ? FIELD.getType ()
: (instance != null ? instance.getClass ()
: null)));
}
public int getPriority () {
return PRIORITY;
}
public boolean isRefreshing () {
return REFRESH;
}
private Object [] context;
public void rememberContext (Object ... args) {
this.context = args;
}
public T getInstance () {
return instance;
}
public List > getRequiredTokens (boolean deleteVarArgs) {
List > result = new ArrayList <> ();
if (TOKEN != null) {
Arrays.asList (TOKEN.getDeclaredConstructors ()).stream ()
. filter (c -> Modifier.isPublic (c.getModifiers ()))
. filter (c -> {
for (Class type : c.getParameterTypes ()) {
if (type.isPrimitive ()) { return false; }
}
return true;
})
. sorted ((a, b) -> {
int argsA = a.getParameterCount (), argsB = b.getParameterCount ();
argsA -= a.isVarArgs () ? 1 : 0; argsB -= b.isVarArgs () ? 1 : 0;
return Integer.compare (argsA, argsB);
})
. limit (1)
. flatMap (c -> {
Class [] types = c.getParameterTypes ();
if (c.isVarArgs () && deleteVarArgs) {
Class [] tmp = new Class [types.length - 1];
System.arraycopy (types, 0, tmp, 0, tmp.length);
types = tmp; // for 1 argument less b/c it's varArgs
}
return Stream.of (types);
})
. forEach (result::add);
} else if (METHOD != null) {
for (Class type : METHOD.getParameterTypes ()) {
if (type.isPrimitive ()) {
String message = String.format ("Snowflake method %s can't have "
+ "primitive arguments", METHOD.getName ());
throw new IllegalStateException (message);
}
result.add (type);
}
}
return result;
}
public List > getRequiredTokens () {
return getRequiredTokens (true);
}
private boolean inputMatches (Object... input) {
List > need = getRequiredTokens ();
if (need.size () != input.length) { return false; }
for (int i = 0; i < need.size (); i++) {
if (input [i] == null) { continue; }
final Class token = need.get (i);
if (!token.isAssignableFrom (input [i].getClass ())) {
return false;
}
}
return true;
}
public T init () {
Objects.requireNonNull (context);
return this.init (context);
}
public T init (SnowballContext context) {
final T result = this.init ();
initFields (context, result);
return result;
}
public static void initFields (SnowballContext context, Object instance) {
Arrays.asList (instance.getClass ().getDeclaredFields ()).forEach (f -> {
try {
final Class type = f.getType ();
f.setAccessible (true);
if (Modifier.isStatic (f.getModifiers ())) { return; }
if (Modifier.isFinal (f.getModifiers ())) { return; }
if (type.isPrimitive ()) { return; }
if (f.get (instance) != null) { return; } // already initialized
if (f.isAnnotationPresent (Snowflake.class)) {
if (f.getAnnotation (Snowflake.class).manual ()) {
return; // field will be initialized manually
}
}
f.set (instance, context.getSnowflakeFor (type));
System.out.println (type + " " + context.registeredSnowflakes.get (type));
if (context.registeredSnowflakes.get (type).isRefreshing ()) {
initFields (context, f.get (instance));
}
} catch (Exception e) { e.printStackTrace (); }
});
}
public T init (Object ... args) {
Objects.requireNonNull (args);
if (instance != null && !REFRESH) {
return instance;
}
try {
if (TOKEN != null && inputMatches (args)) {
Class [] types = getRequiredTokens (false)
. toArray (new Class [0]);
@SuppressWarnings ("unchecked")
Constructor constructor = (Constructor ) TOKEN
. getConstructor (types);
if (constructor.isVarArgs ()) {
Object [] tmp = new Object [args.length + 1];
if (args.length > 0) {
System.arraycopy (args, 0, tmp, 0, tmp.length);
}
Class stub = types [types.length - 1].getComponentType ();
tmp [args.length] = Array.newInstance (stub, 0);
args = tmp;
}
return this.instance = constructor.newInstance (args);
} else if (FIELD != null) {
@SuppressWarnings ("unchecked")
final T result = (T) FIELD.get (null);
this.instance = result;
return result;
} else if (METHOD != null && inputMatches (args)) {
Class [] types = getRequiredTokens (false)
. toArray (new Class [0]);
if (METHOD.isVarArgs ()) {
Object [] tmp = new Object [args.length + 1];
if (args.length > 0) {
System.arraycopy (args, 0, tmp, 0, tmp.length);
}
Class stub = types [types.length - 1].getComponentType ();
tmp [args.length] = Array.newInstance (stub, 0);
args = tmp;
}
@SuppressWarnings ("unchecked")
final T result = (T) METHOD.invoke (null, args);
this.instance = result;
return result;
}
} catch (Exception e) { e.printStackTrace (); }
return instance;
}
}
