/
EmptyObjectsProvider.java
42 lines (33 loc) · 1.39 KB
/
EmptyObjectsProvider.java
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package br.com.caelum.iogi;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import br.com.caelum.iogi.reflection.Target;
import br.com.caelum.iogi.spi.DependencyProvider;
import com.google.common.base.Supplier;
import com.google.common.collect.ImmutableMap;
public class EmptyObjectsProvider implements DependencyProvider {
public static final Map<? extends Class<?>, ? extends Supplier<?>> JAVA_EMPTY_SUPPLIERS = ImmutableMap.of(List.class,
new Supplier<List<Object>>() {
public List<Object> get() {
return new ArrayList<Object>();
};
});
private final Map<? extends Class<?>, ? extends Supplier<?>> emptyInstances;
private final DependencyProvider underlying;
public EmptyObjectsProvider(DependencyProvider underlying, Map<? extends Class<?>, ? extends Supplier<?>> emptyInstances) {
this.underlying = underlying;
this.emptyInstances = emptyInstances;
}
@Override
public boolean canProvide(Target<?> target) {
return selfCanProvide(target) || underlying.canProvide(target);
}
private boolean selfCanProvide(Target<?> target) {
return emptyInstances.containsKey(target.getClassType());
}
@Override
public Object provide(Target<?> target) {
return underlying.canProvide(target) ? underlying.provide(target) : emptyInstances.get(target.getClassType()).get();
}
}