/**
 * END USER LICENSE AGREEMENT (“EULA”)
 *
 * READ THIS AGREEMENT CAREFULLY (date: 9/13/2011):
 * http://www.akiban.com/licensing/20110913
 *
 * BY INSTALLING OR USING ALL OR ANY PORTION OF THE SOFTWARE, YOU ARE ACCEPTING
 * ALL OF THE TERMS AND CONDITIONS OF THIS AGREEMENT. YOU AGREE THAT THIS
 * AGREEMENT IS ENFORCEABLE LIKE ANY WRITTEN AGREEMENT SIGNED BY YOU.
 *
 * IF YOU HAVE PAID A LICENSE FEE FOR USE OF THE SOFTWARE AND DO NOT AGREE TO
 * THESE TERMS, YOU MAY RETURN THE SOFTWARE FOR A FULL REFUND PROVIDED YOU (A) DO
 * NOT USE THE SOFTWARE AND (B) RETURN THE SOFTWARE WITHIN THIRTY (30) DAYS OF
 * YOUR INITIAL PURCHASE.
 *
 * IF YOU WISH TO USE THE SOFTWARE AS AN EMPLOYEE, CONTRACTOR, OR AGENT OF A
 * CORPORATION, PARTNERSHIP OR SIMILAR ENTITY, THEN YOU MUST BE AUTHORIZED TO SIGN
 * FOR AND BIND THE ENTITY IN ORDER TO ACCEPT THE TERMS OF THIS AGREEMENT. THE
 * LICENSES GRANTED UNDER THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON ACCEPTANCE
 * BY SUCH AUTHORIZED PERSONNEL.
 *
 * IF YOU HAVE ENTERED INTO A SEPARATE WRITTEN LICENSE AGREEMENT WITH AKIBAN FOR
 * USE OF THE SOFTWARE, THE TERMS AND CONDITIONS OF SUCH OTHER AGREEMENT SHALL
 * PREVAIL OVER ANY CONFLICTING TERMS OR CONDITIONS IN THIS AGREEMENT.
 */

package com.akiban.server.types3.mcompat.aggr;

import com.akiban.server.types3.TAggregator;
import com.akiban.server.types3.TAggregatorBase;
import com.akiban.server.types3.TInstance;
import com.akiban.server.types3.TOverloadResult;
import com.akiban.server.types3.pvalue.PValue;
import com.akiban.server.types3.pvalue.PValueSource;
import com.akiban.server.types3.pvalue.PValueTarget;

public class MFirst extends TAggregatorBase {

    public static final TAggregator[] INSTANCES = {
        new MFirst ("first"),
    };
    
    protected MFirst(String name) {
        super(name, null);
        first = false;
    }

    @Override
    public void input(TInstance instance, PValueSource source,
            TInstance stateType, PValue state, Object option) {
        // TODO: Implement this function
    }

    @Override
    public void emptyValue(PValueTarget state) {
        state.putNull();
    }

    @Override
    public TOverloadResult resultType() {
        return TOverloadResult.picking();
    }
    
    private boolean first; 
    private PValueSource source; 

}

/**
 * END USER LICENSE AGREEMENT (“EULA”)
 *
 * READ THIS AGREEMENT CAREFULLY (date: 9/13/2011):
 * http://www.akiban.com/licensing/20110913
 *
 * BY INSTALLING OR USING ALL OR ANY PORTION OF THE SOFTWARE, YOU ARE ACCEPTING
 * ALL OF THE TERMS AND CONDITIONS OF THIS AGREEMENT. YOU AGREE THAT THIS
 * AGREEMENT IS ENFORCEABLE LIKE ANY WRITTEN AGREEMENT SIGNED BY YOU.
 *
 * IF YOU HAVE PAID A LICENSE FEE FOR USE OF THE SOFTWARE AND DO NOT AGREE TO
 * THESE TERMS, YOU MAY RETURN THE SOFTWARE FOR A FULL REFUND PROVIDED YOU (A) DO
 * NOT USE THE SOFTWARE AND (B) RETURN THE SOFTWARE WITHIN THIRTY (30) DAYS OF
 * YOUR INITIAL PURCHASE.
 *
 * IF YOU WISH TO USE THE SOFTWARE AS AN EMPLOYEE, CONTRACTOR, OR AGENT OF A
 * CORPORATION, PARTNERSHIP OR SIMILAR ENTITY, THEN YOU MUST BE AUTHORIZED TO SIGN
 * FOR AND BIND THE ENTITY IN ORDER TO ACCEPT THE TERMS OF THIS AGREEMENT. THE
 * LICENSES GRANTED UNDER THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON ACCEPTANCE
 * BY SUCH AUTHORIZED PERSONNEL.
 *
 * IF YOU HAVE ENTERED INTO A SEPARATE WRITTEN LICENSE AGREEMENT WITH AKIBAN FOR
 * USE OF THE SOFTWARE, THE TERMS AND CONDITIONS OF SUCH OTHER AGREEMENT SHALL
 * PREVAIL OVER ANY CONFLICTING TERMS OR CONDITIONS IN THIS AGREEMENT.
 */

package com.akiban.server.types3.mcompat.aggr;

import com.akiban.server.types3.TAggregator;
import com.akiban.server.types3.TAggregatorBase;
import com.akiban.server.types3.TInstance;
import com.akiban.server.types3.TOverloadResult;
import com.akiban.server.types3.pvalue.PValue;
import com.akiban.server.types3.pvalue.PValueSource;
import com.akiban.server.types3.pvalue.PValueTarget;
import com.akiban.server.types3.pvalue.PValueTargets;

public class MFirst extends TAggregatorBase {

    public static final TAggregator[] INSTANCES = {
        new MFirst ("first"),
    };
    
    protected MFirst(String name) {
        super(name, null);
        first = false;
    }

    @Override
    public void input(TInstance instance, PValueSource source,
            TInstance stateType, PValue state, Object option) {
        if (source.isNull())
            return;
        
        if (!first) {
            PValueTargets.copyFrom(source, state);
            first = true;
            return;
        }
    }

    @Override
    public void emptyValue(PValueTarget state) {
        state.putNull();
    }

    @Override
    public TOverloadResult resultType() {
        return TOverloadResult.picking();
    }
    
    private boolean first; 
}

Implement MFirst