org.apache.juneau.utils.MetadataMap Maven / Gradle / Ivy
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// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance *
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// * *
// * http://www.apache.org/licenses/LICENSE-2.0 *
// * *
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// ***************************************************************************************************************************
package org.apache.juneau.utils;
import static org.apache.juneau.internal.ClassUtils.*;
import java.lang.reflect.*;
import org.apache.juneau.*;
/**
* Utility class for quick lookup of class metadata instances.
*
*
* Class instances are created once and then cached.
*
*
* Classes must have a constructor that takes in a single argument.
*/
public class MetadataMap {
private Class[] classes = new Class[0];
private Object[] metadata = new Object[0];
/**
* Constructor.
*
* @param c The metadata class to create.
* @param constructorArg The argument needed to construct the metadata.
* @return The cached metadata object.
*/
@SuppressWarnings("unchecked")
public T get(Class c, Object constructorArg) {
for (int i = 0; i < classes.length; i++)
if (classes[i] == c)
return (T)metadata[i];
synchronized(this) {
for (int i = 0; i < classes.length; i++)
if (classes[i] == c)
return (T)metadata[i];
Class[] classes2 = new Class[classes.length + 1];
Object[] metadata2 = new Object[classes.length + 1];
for (int i = 0; i < classes.length; i++) {
classes2[i] = classes[i];
metadata2[i] = metadata[i];
}
Object o = null;
try {
for (Constructor con : c.getConstructors()) {
Class[] pt = con.getParameterTypes();
if (pt.length == 1 && isParentClass(pt[0], constructorArg.getClass())) {
o = con.newInstance(constructorArg);
break;
}
}
} catch (InvocationTargetException e) {
Throwable t = e.getTargetException();
if (t instanceof RuntimeException)
throw (RuntimeException)t;
throw new RuntimeException(t);
} catch (Exception e) {
throw new RuntimeException(e);
}
if (o == null)
throw new BeanRuntimeException(c,
"Could not find a constructor on class with a parameter to handle type {0}", constructorArg.getClass());
classes2[classes.length] = c;
metadata2[classes.length] = o;
classes = classes2;
metadata = metadata2;
return (T)o;
}
}
}