/*
 * 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
 *
 *      http://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.catalina.ant.jmx;


import java.util.Set;

import javax.management.MBeanAttributeInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanServerConnection;
import javax.management.ObjectName;

import org.apache.tools.ant.BuildException;


/**
 * Query for Mbeans.
 * <ul>
 * <li>open no existing JSR 160 rmi jmx connection</li>
 * <li>Get all Mbeans attributes</li>
 * <li>Get only the Query Mbeans ObjectNames</li>
 * <li>Show query result as Ant console log</li>
 * <li>Bind query result as Ant properties</li>
 * </ul>
 * <br>
 * Query a list of Mbeans.
 *
 * <pre>
 *   &lt;jmxQuery
 *           host="127.0.0.1"
 *           port="9014"
 *           name="Catalina:type=Manager,*
 *           resultproperty="manager" /&gt;
 * </pre>
 *
 * with attribute <em>attributebinding="true"</em> you can get all attributes also from result objects.<br>
 * The property manager.length show the size of the result and with manager.[0..length].name the resulted ObjectNames
 * are saved. These tasks require Ant 1.6 or later interface.
 *
 * @since 5.5.10
 */
public class JMXAccessorQueryTask extends JMXAccessorTask {

    /**
     * Constructs a new JMXAccessorQueryTask.
     */
    public JMXAccessorQueryTask() {
    }

    // ----------------------------------------------------- Instance Variables

    private boolean attributebinding = false;

    // ------------------------------------------------------------- Properties

    /**
     * Get the attribute binding flag.
     *
     * @return the attribute binding flag
     */
    public boolean isAttributebinding() {
        return attributebinding;
    }

    /**
     * Set the attribute binding flag.
     *
     * @param attributeBinding the flag to set
     */
    public void setAttributebinding(boolean attributeBinding) {
        this.attributebinding = attributeBinding;
    }

    // ------------------------------------------------------ protected Methods


    @Override
    public String jmxExecute(MBeanServerConnection jmxServerConnection) throws Exception {
        if (getName() == null) {
            throw new BuildException("Must specify a 'name'");
        }
        if (jmxServerConnection == null) {
            throw new BuildException("Must open a connection!");
        }
        return jmxQuery(jmxServerConnection, getName());
    }


    /**
     * Call Mbean server for some mbeans with same domain, attributes. with <em>attributebinding=true</em> you can save
     * all attributes from all found objects
     *
     * @param jmxServerConnection Connection to the JMX server
     * @param qry                 The query
     *
     * @return null (no error message to report other than exception)
     */
    protected String jmxQuery(MBeanServerConnection jmxServerConnection, String qry) {
        Set<ObjectName> names;
        String resultproperty = getResultproperty();
        try {
            names = jmxServerConnection.queryNames(new ObjectName(qry), null);
            if (resultproperty != null) {
                setProperty(resultproperty + ".Length", Integer.toString(names.size()));
            }
        } catch (Exception e) {
            if (isEcho()) {
                handleErrorOutput(e.getMessage());
            }
            return "Can't query mbeans " + qry;
        }

        if (resultproperty != null) {
            int oindex = 0;
            String pname;
            for (ObjectName oname : names) {
                pname = resultproperty + "." + Integer.toString(oindex) + ".";
                oindex++;
                setProperty(pname + "Name", oname.toString());
                if (isAttributebinding()) {
                    bindAttributes(jmxServerConnection, pname, oname);
                }
            }
        }
        return null;
    }

    /**
     * Bind MBean attributes to Ant properties.
     *
     * @param jmxServerConnection the JMX server connection
     * @param pname the property name prefix
     * @param oname the MBean object name
     */
    protected void bindAttributes(MBeanServerConnection jmxServerConnection, String pname, ObjectName oname) {
        try {
            MBeanInfo minfo = jmxServerConnection.getMBeanInfo(oname);
            MBeanAttributeInfo[] attrs = minfo.getAttributes();
            Object value;

            for (MBeanAttributeInfo attr : attrs) {
                if (!attr.isReadable()) {
                    continue;
                }
                String attName = attr.getName();
                if (attName.indexOf('=') >= 0 || attName.indexOf(':') >= 0 || attName.indexOf(' ') >= 0) {
                    continue;
                }

                try {
                    value = jmxServerConnection.getAttribute(oname, attName);
                } catch (Exception e) {
                    if (isEcho()) {
                        handleErrorOutput(
                                "Error getting attribute " + oname + " " + pname + attName + " " + e.toString());
                    }
                    continue;
                }
                if (value == null || "modelerType".equals(attName)) {
                    continue;
                }
                createProperty(pname + attName, value);
            }
        } catch (Exception e) {
            // Ignore
        }
    }
}
