com.disney.groovity.model.ModelCopier Maven / Gradle / Ivy
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* © 2018 Disney | ABC Television Group
*
* Licensed under the Apache License, Version 2.0 (the "Apache License")
* with the following modification; you may not use this file except in
* compliance with the Apache License and the following modification to it:
* Section 6. Trademarks. is deleted and replaced with:
*
* 6. Trademarks. This License does not grant permission to use the trade
* names, trademarks, service marks, or product names of the Licensor
* and its affiliates, except as required to comply with Section 4(c) of
* the License and to reproduce the content of the NOTICE file.
*
* You may obtain a copy of the Apache License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the Apache License with the above modification is
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package com.disney.groovity.model;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Map;
/**
* Utility class for recursively deep-copying Models, Maps, Collections and Arrays, using an IdentityHashMap to copy circular references
* without going into stack overflow
*
* @author Alex Vigdor
*/
public class ModelCopier {
final IdentityHashMap copied = new IdentityHashMap<>();
private final Object makeNew(Class c) {
try {
return c.newInstance();
} catch (InstantiationException | IllegalAccessException e) {
throw new RuntimeException(e);
}
}
@SuppressWarnings({ "rawtypes", "unchecked" })
public final Object copy(final Object o) {
if(o==null) {
return null;
}
final Class c = o.getClass();
if(o instanceof Model) {
final Object precopy = copied.get(o);
if(precopy != null) {
return precopy;
}
final Model m = (Model) o;
final Model to = (Model) makeNew(c);
copied.put(o, to);
m.each((k,v)->{
to.put(k, copy(v));
});
return to;
}
if(o instanceof Map) {
if(o == Collections.EMPTY_MAP) {
return o;
}
final Object precopy = copied.get(o);
if(precopy != null) {
return precopy;
}
final Map from = (Map)o;
final Map to = (Map) makeNew(c);
copied.put(o, to);
for(java.util.Map.Entry e: from.entrySet()) {
to.put(e.getKey(), copy(e.getValue()));
}
return to;
}
if(o instanceof Collection) {
if(o == Collections.EMPTY_LIST || o == Collections.EMPTY_SET) {
return o;
}
final Object precopy = copied.get(o);
if(precopy != null) {
return precopy;
}
final Collection from = (Collection) o;
final Collection to = (Collection) makeNew(c);
copied.put(o, to);
for(Object f: from) {
to.add(copy(f));
}
return to;
}
if(c.isArray()) {
final int len = Array.getLength(o);
if(len == 0) {
return o;
}
final Object precopy = copied.get(o);
if(precopy != null) {
return precopy;
}
final Class ct = c.getComponentType();
if(ct.isPrimitive()) {
final Object to = Array.newInstance(ct,len);
System.arraycopy(o, 0, to, 0, len);
copied.put(o, to);
return to;
}
else {
final Object[] oa = (Object[]) o;
final Object[] to = (Object[]) Array.newInstance(ct, len);
copied.put(o, to);
for(int i=0; i < len; i++) {
to[i] = copy(oa[i]);
}
return to;
}
}
return o;
}
}