src/test/java/org/apache/commons/dbutils/MockResultSetMetaData.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.dbutils;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.sql.ResultSetMetaData;

/**
 * MockResultSetMetaData dynamically implements the ResultSetMetaData interface.
 */
public class MockResultSetMetaData implements InvocationHandler {

    /**
     * Create a {@code MockResultSetMetaData} proxy object. This is equivalent to:
     *
     * <pre>
     * ProxyFactory.instance().createResultSetMetaData(new MockResultSetMetaData(columnNames));
     * </pre>
     *
     * @param columnNames
     * @return the proxy object
     */
    public static ResultSetMetaData create(final String[] columnNames) {
        return ProxyFactory.instance().createResultSetMetaData(new MockResultSetMetaData(columnNames));
    }

    private final String[] columnNames;

    private final String[] columnLabels;

    public MockResultSetMetaData(final String[] columnNames) {
        this.columnNames = columnNames;
        this.columnLabels = new String[columnNames.length];

    }

    public MockResultSetMetaData(final String[] columnNames, final String[] columnLabels) {
        this.columnNames = columnNames;
        this.columnLabels = columnLabels;
    }

    @Override
    public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
        final String methodName = method.getName();
        switch (methodName) {
        case "getColumnCount":
            return Integer.valueOf(this.columnNames.length);
        case "getColumnName":
            final int col1 = ((Integer) args[0]).intValue() - 1;
            return this.columnNames[col1];
        case "getColumnLabel":
            final int col2 = ((Integer) args[0]).intValue() - 1;
            return this.columnLabels[col2];
        case "hashCode":
            return Integer.valueOf(System.identityHashCode(proxy));
        case "toString":
            return "MockResultSetMetaData " + System.identityHashCode(proxy);
        case "equals":
            return Boolean.valueOf(proxy == args[0]);
        default:
            break;
        }
        throw new UnsupportedOperationException("Unsupported method: " + methodName);
    }
}