BaseCloser.java

package voldemort.store.readonly.io;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public abstract class BaseCloser<T> {

    protected List<T> delegates = new ArrayList();

    private Throwable cause = null;

    private boolean executed = false;

    public BaseCloser() {}

    public BaseCloser(List<T> delegates) {
        this.delegates = delegates;
    }

    public BaseCloser(T... delegates) {
        add(delegates);
    }

    public void add(T delegate) {
        delegates.add(delegate);
    }

    public void add(T... delegates) {
        for(T current: delegates) {
            this.delegates.add(current);
        }
    }

    public void setCause(Throwable cause) {
        this.cause = cause;
    }

    protected boolean executed() {
        return executed;
    }

    protected void exec() throws GroupIOException {

        if(executed)
            return;

        GroupIOException exc = null;

        if(cause != null)
            exc = new GroupIOException(cause);

        for(T current: delegates) {

            if(current == null)
                continue;

            try {

                onDelegate(current);

            } catch(Throwable t) {

                if(exc == null) {
                    exc = new GroupIOException(t);
                } else {
                    exc.addSuppressedException(t);
                }

            }

        }

        executed = true;

        if(exc != null)
            throw exc;

    }

    protected abstract void onDelegate(T delegate) throws IOException;

}