net.ttddyy.dsproxy.proxy.CachedRowSetResultSetProxyLogic Maven / Gradle / Ivy

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Provide a datasource proxy that can inject your own logic into all queries.
There is a newer version: 1.10
package net.ttddyy.dsproxy.proxy;

import net.ttddyy.dsproxy.ConnectionInfo;
import net.ttddyy.dsproxy.listener.MethodExecutionListenerUtils;

import java.lang.reflect.Method;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * Uses {@link javax.sql.rowset.CachedRowSet} to provide repeatable read {@link ResultSet} proxy.
 *
 * {@link javax.sql.rowset.CachedRowSet} is disconnected scrollable {@link javax.sql.RowSet} which is a
 * subset of {@link ResultSet}. Using those feature to provide repeatable read resultset proxy.
 *
 * The default oracle jdk implementation {@code com.sun.rowset.CachedRowSetImpl} does not support {@code isClosed}
 * method. Thus, keep close status and return it when {@code isClosed()} is called.
 *
 * @author Tadaya Tsuyukubo
 * @see CachedRowSetResultSetProxyLogicFactory
 * @since 1.4.7
 */
public class CachedRowSetResultSetProxyLogic implements ResultSetProxyLogic {

    private ResultSet resultSet;  // original resultset
    private ResultSet cachedRowSet;
    private ConnectionInfo connectionInfo;
    private ProxyConfig proxyConfig;

    // default impl "com.sun.rowset.CachedRowSetImpl" does NOT support "isClosed()", so enable handling in this class
    protected boolean supportIsClosedMethod = true;
    protected boolean isClosed;

    public CachedRowSetResultSetProxyLogic(ResultSet resultSet, ResultSet cachedRowSet, ConnectionInfo connectionInfo, ProxyConfig proxyConfig) {
        this.resultSet = resultSet;
        this.cachedRowSet = cachedRowSet;
        this.connectionInfo = connectionInfo;
        this.proxyConfig = proxyConfig;
    }

    @Override
    public Object invoke(Method method, Object[] args) throws Throwable {
        return MethodExecutionListenerUtils.invoke(new MethodExecutionListenerUtils.MethodExecutionCallback() {
            @Override
            public Object execute(Object proxyTarget, Method method, Object[] args) throws Throwable {
                return performQueryExecutionListener(method, args);
            }
        }, this.proxyConfig, this.cachedRowSet, this.connectionInfo, method, args);
    }

    private Object performQueryExecutionListener(Method method, Object[] args) throws Throwable {

        String methodName = method.getName();

        if ("toString".equals(methodName)) {
            final StringBuilder sb = new StringBuilder();
            sb.append(this.resultSet.getClass().getSimpleName());
            sb.append(" [");
            sb.append(this.resultSet.toString());
            sb.append("]");
            return sb.toString(); // differentiate toString message.
        } else if ("hashCode".equals(methodName)) {
            return this.resultSet.hashCode();  // returns original resultset hashcode
        } else if ("equals".equals(methodName)) {
            return this.resultSet.equals(args[0]);  // compare with original resultset
        }

        if ("close".equals(methodName)) {
            this.isClosed = true;
        } else if ("getTarget".equals(methodName)) {
            // ProxyJdbcObject interface has a method to return original object.
            return this.resultSet;
        }

        if (this.supportIsClosedMethod && "isClosed".equals(methodName)) {
            return this.isClosed;
        }

        // TODO: handle getStatement() method to return proxied statement

        try {
            return MethodUtils.proceedExecution(method, this.cachedRowSet, args);
        } catch (Throwable throwable) {
            if (throwable instanceof SQLException) {
                throw throwable;
            }
            // convert any exception to SQLException.
            String reason = String.format("CachedRowSet threw exception: %s", throwable);
            throw new SQLException(reason, throwable);
        }
    }
}