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Panda Core is the core module of Panda Framework, it contains commonly used utility classes similar to apache-commons.
package panda.cast;
import java.lang.reflect.Type;
import java.util.Map;
import panda.lang.CycleDetectStrategy;
import panda.lang.Exceptions;
import panda.lang.Objects;
import panda.lang.Strings;
import panda.lang.collection.KeyValue;
import panda.lang.reflect.Types;
import panda.log.Log;
import panda.log.Logs;
/**
* Castor interface
*
* @param source type
* @param target type
*
*/
public abstract class AbstractCastor implements Castor {
protected final static Log log = Logs.getLog(AbstractCastor.class);
protected final Type fromType;
protected final Type toType;
public AbstractCastor(Type fromType, Type toType) {
this.fromType = fromType;
this.toType = toType;
}
/**
* @return the from type
*/
protected Type getFromType() {
return fromType;
}
/**
* @return the to type
*/
protected Type getToType() {
return toType;
}
protected T createTarget() {
try {
return Types.newInstance(Types.getDefaultImplType(toType));
}
catch (InstantiationException e) {
throw new CastException(e);
}
catch (IllegalAccessException e) {
throw new CastException(e);
}
}
protected boolean isObjectType(Type type) {
return type == null || Object.class.equals(Types.getRawType(type));
}
/**
* cast value
* @param context context
* @param value value
* @return casted value
*/
@Override
@SuppressWarnings("unchecked")
public T cast(S value, CastContext context) {
if (log.isTraceEnabled()) {
log.trace("cast " + context.toPath() + ": "
+ (value == null ? "NULL" : value.getClass().toString())
+ " -> " + Types.getRawType(toType).toString());
}
try {
if (value == null) {
return defaultValue();
}
if (isAssignable(value)) {
return (T)value;
}
return castValue(value, context);
}
catch (Throwable e) {
throw wrapError(e, context);
}
}
/**
* cast value to the provided target object,
* NOTE: if the target is not a mutable object, a new object will be returned.
* @param value value
* @param target target object
* @return casted value
*/
@Override
public T castTo(S value, T target) {
return castTo(value, target, null);
}
/**
* cast value to the provided target object,
* NOTE: if the target is not a mutable object, a new object will be returned.
* @param value value
* @param target target object
* @param context context
* @return casted value
*/
@Override
public T castTo(S value, T target, CastContext context) {
if (log.isTraceEnabled()) {
log.trace("castTo " + context.toPath() + ": "
+ (value == null ? "NULL" : value.getClass().toString())
+ " -> " + Objects.identityToString(target));
}
try {
if (value == null) {
return defaultValue();
}
return castValueTo(value, target, context);
}
catch (Throwable e) {
throw wrapError(e, context);
}
}
protected T defaultValue() {
return null;
}
protected boolean isAssignable(Object value) {
return Types.isAssignable(value.getClass(), toType, false);
}
/**
* cast value
* @param value source value (not null)
* @param context context
* @return casted value
*/
protected abstract T castValue(S value, CastContext context);
/**
* cast value to target
* @param value source value (not null)
* @param target target value
* @param context context
* @return casted value
*/
protected T castValueTo(S value, T target, CastContext context) {
throw Exceptions.unsupported("CastValueTo(" + (value == null ? "NULL" : value.getClass())
+ ", " + (target == null ? "NULL" : target.getClass()) + ") is not supported");
}
protected CastException wrapError(Throwable e, CastContext context) {
if (e instanceof CastException) {
return (CastException)e;
}
return new CastException("Cast Exception at " + context.toPath() + ": " + e.getMessage(), e);
}
protected CastException cycleError(CastContext context, String name, Object value) {
throw new CastException("Cycle object detected: " + context.toPath(name) + " : " + Objects.identityToString(value));
}
protected String castErrorMsg(Object value, CastContext context) {
return context.toPath() + ": Failed to cast "
+ (value == null ? "null" : value.getClass())
+ (value instanceof CharSequence ? ("[" + Strings.left((CharSequence)value, 20) + "]") : "")
+ " -> "
+ Types.getRawType(toType);
}
protected T castError(Object value, CastContext context, Throwable e) {
if (context.isSkipCastError()) {
context.addError(context.toName(), value);
return defaultValue();
}
throw new CastException(castErrorMsg(value, context), e);
}
protected T castError(Object value, CastContext context) {
if (context.isSkipCastError()) {
context.addError(context.toName(), value);
return defaultValue();
}
throw new CastException(castErrorMsg(value, context));
}
protected Castor getCastor(CastContext context, Type fromType, Type toType) {
return context.getCastors().getCastor(fromType, toType);
}
@SuppressWarnings({ "rawtypes", "unchecked" })
protected Object castChild(CastContext context, Castor conv, int index, Object value) {
if (value == null) {
return conv.cast(value, context);
}
String name = String.valueOf(index);
if (context.isCycled(value)) {
switch (context.getCycleDetectStrategy()) {
case CycleDetectStrategy.CYCLE_DETECT_NOPROP:
case CycleDetectStrategy.CYCLE_DETECT_LENIENT:
return null;
default:
throw cycleError(context, name, value);
}
}
context.push(name, value);
try {
return conv.cast(value, context);
}
finally {
context.popup();
}
}
@SuppressWarnings({ "rawtypes", "unchecked" })
protected Map.Entry castChild(CastContext context, Castor keyCastor, Castor valCastor, String name, Object key, Object value) {
if (key == null) {
key = keyCastor.cast(key, context);
}
else {
if (context.isCycled(key)) {
switch (context.getCycleDetectStrategy()) {
case CycleDetectStrategy.CYCLE_DETECT_NOPROP:
case CycleDetectStrategy.CYCLE_DETECT_LENIENT:
return null;
default:
throw cycleError(context, name, key);
}
}
context.push(name, key);
try {
key = keyCastor.cast(key, context);
}
finally {
context.popup();
}
}
if (value == null) {
value = valCastor.cast(value, context);
}
else {
if (context.isCycled(key)) {
switch (context.getCycleDetectStrategy()) {
case CycleDetectStrategy.CYCLE_DETECT_NOPROP:
return null;
case CycleDetectStrategy.CYCLE_DETECT_LENIENT:
value = null;
break;
default:
throw cycleError(context, name, value);
}
}
context.push(name, value);
try {
value = valCastor.cast(value, context);
}
finally {
context.popup();
}
}
return new KeyValue(key, value);
}
@Override
public String toString() {
return Objects.toStringBuilder()
.append("fromType", fromType)
.append("toType", toType)
.toString();
}
}