Remove duplicate code in ConstantPool class

Motivation:

Currently, valueOf() and newInstance() use almost same code to create new constant.
For maintainability, it's better to share duplicate code among them.

Motification:

Added new private functions.
- checkNotNullAndNotEmpty() is for checking whether the name of a constant is null and empty.
- newConstant0() is for creating a new constant.

Result:

- Compact source code
- Improvement of maintainability
This commit is contained in:
JongYoon Lim 2015-04-15 17:55:49 +09:00 committed by Norman Maurer
parent e3980a6487
commit 5a9da7c5ba

View File

@ -55,31 +55,24 @@ public abstract class ConstantPool<T extends Constant<T>> {
* @param name the name of the {@link Constant}
*/
public T valueOf(String name) {
if (name == null) {
throw new NullPointerException("name");
}
if (name.isEmpty()) {
throw new IllegalArgumentException("empty name");
}
T c;
synchronized (constants) {
T c = constants.get(name);
if (c == null) {
c = newConstant(nextId, name);
constants.put(name, c);
nextId ++;
if (exists(name)) {
c = constants.get(name);
} else {
c = newInstance0(name);
}
return c;
}
return c;
}
/**
* Returns {@code true} if a {@link AttributeKey} exists for the given {@code name}.
*/
public boolean exists(String name) {
ObjectUtil.checkNotNull(name, "name");
checkNotNullAndNotEmpty(name);
synchronized (constants) {
return constants.containsKey(name);
}
@ -91,25 +84,33 @@ public abstract class ConstantPool<T extends Constant<T>> {
*/
@SuppressWarnings("unchecked")
public T newInstance(String name) {
if (name == null) {
throw new NullPointerException("name");
if (exists(name)) {
throw new IllegalArgumentException(String.format("'%s' is already in use", name));
}
T c = newInstance0(name);
return c;
}
// Be careful that this dose not check whether the argument is null or empty.
private T newInstance0(String name) {
synchronized (constants) {
T c = newConstant(nextId, name);
constants.put(name, c);
nextId++;
return c;
}
}
private String checkNotNullAndNotEmpty(String name) {
ObjectUtil.checkNotNull(name, "name");
if (name.isEmpty()) {
throw new IllegalArgumentException("empty name");
}
synchronized (constants) {
T c = constants.get(name);
if (c == null) {
c = newConstant(nextId, name);
constants.put(name, c);
nextId ++;
} else {
throw new IllegalArgumentException(String.format("'%s' is already in use", name));
}
return c;
}
return name;
}
protected abstract T newConstant(int id, String name);