Java tutorial
package com.tesora.dve.sql.node.expression; /* * #%L * Tesora Inc. * Database Virtualization Engine * %% * Copyright (C) 2011 - 2014 Tesora Inc. * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License, version 3, * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * #L% */ import java.util.Collections; import java.util.List; import org.apache.commons.lang.StringUtils; import com.tesora.dve.sql.node.Edge; import com.tesora.dve.sql.node.EdgeName; import com.tesora.dve.sql.node.LanguageNode; import com.tesora.dve.sql.node.SingleEdge; import com.tesora.dve.sql.parser.SourceLocation; import com.tesora.dve.sql.transform.CopyContext; public class IntervalExpression extends ExpressionNode { private final SingleEdge<IntervalExpression, ExpressionNode> target = new SingleEdge<IntervalExpression, ExpressionNode>( IntervalExpression.class, this, EdgeName.INTERVAL_TARGET); String unit = null; public IntervalExpression(ExpressionNode expr_unit, String unit, SourceLocation orig) { super(orig); this.target.set(expr_unit); this.unit = unit; } @SuppressWarnings("unchecked") @Override public <T extends Edge<?, ?>> List<T> getEdges() { return (List<T>) Collections.singletonList(target); } @Override protected LanguageNode copySelf(CopyContext cc) { IntervalExpression nfc = new IntervalExpression(target.get(), unit, null); return nfc; } public ExpressionNode getExpr_unit() { return target.get(); } public String getUnit() { return unit; } @Override protected boolean schemaSelfEqual(LanguageNode other) { IntervalExpression ofc = (IntervalExpression) other; return StringUtils.equals(unit, ofc.getUnit()); } @Override protected int selfHashCode() { return unit.hashCode(); } }