org.directwebremoting.extend.EnginePrivate Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.
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/*
 * Copyright 2005 Joe Walker
 *
 * Licensed 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.directwebremoting.extend;

import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.util.JavascriptUtil;

/**
 * An abstraction of the dwr.engine Javascript class.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class EnginePrivate
{
    /**
     * Begin wrapper with variable alias to do remote calls on the correct DWR instance.
     * @param instanceId DWR instance id from browser
     * @param useWindowParent should this alias target the same window or the parent window?
     * @return JavaScript snippet to be used by other remote calls
     */
    public static String remoteBeginWrapper(String instanceId, boolean useWindowParent, String documentDomain)
    {
        StringBuilder buf = new StringBuilder();
        if (documentDomain != null && !documentDomain.equals("")) {
            buf.append("document.domain='").append(documentDomain).append("';\r\n");
        }
        if (useWindowParent)
        {
        	// We need to protect from access exceptions f ex when a discarded
        	// iframe receives data and IE6/7 complains about "freed script"
            buf.append("try{\r\n");
            buf.append("if(window.parent.dwr){\r\n");
            buf.append("var dwr=window.parent.dwr._[" + instanceId + "];");
        }
        else
        {
            buf.append("(function(){\r\n");
            buf.append("if(!window.dwr)return;\r\n");
            buf.append("var dwr=window.dwr._[" + instanceId + "];");
        }
        return buf.toString();
    }

    /**
     * End wrapper with variable alias to do remote calls on the correct DWR instance.
     * @param instanceId DWR instance id from browser
     * @param useWindowParent should this alias target the same window or the parent window?
     * @return JavaScript snippet to be used by other remote calls
     */
    public static String remoteEndWrapper(String instanceId, boolean useWindowParent)
    {
        StringBuilder buf = new StringBuilder();
        if (useWindowParent)
        {
            buf.append("dwr.engine.transport.iframe.remote.endChunk(window);\r\n");
            buf.append("}\r\n");
            buf.append("}catch(e){}");
        } else {
            buf.append("})();");
        }
        return buf.toString();
    }

    /**
     * Call the dwr.engine.remote.handleResponse() in the browser
     * @param batchId The identifier of the batch that we are handling a response for
     * @param callId The identifier of the call that we are handling a response for
     * @param data The data to pass to the callback function
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteHandleCallbackScript(String batchId, String callId, Object data)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleCallback", batchId, callId, data);
        return script;
    }

    /**
     * Call dwr.engine.remote.handleException() in the browser
     * @param batchId The identifier of the batch that we are handling a response for
     * @param callId The id of the call we are replying to
     * @param ex The exception to throw on the remote end
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteHandleExceptionScript(String batchId, String callId, Throwable ex)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleException", batchId, callId, ex);
        return script;
    }

    /**
     * Call dwr.engine.remote.handleReverseAjax() in the browser
     * @param scriptIndex
     * @param script
     */
    public static String getRemoteHandleReverseAjaxScript(long scriptIndex, String script)
    {
        StringBuffer strbuf = new StringBuffer();
        strbuf.append("dwr.engine.remote.handleReverseAjax(").append(scriptIndex).append(",function(){\r\n");
        strbuf.append(script).append("\r\n");
        strbuf.append("});");
        return strbuf.toString();
    }

    /**
     * Call dwr.engine.remote.handleServerException() in the browser
     * @param batchId The identifier of the batch that we are handling a response for
     * @param ex The exception from which we make a reply
     * @return The script to send to the browser
     */
    public static String getRemoteHandleBatchExceptionScript(String batchId, Exception ex)
    {
        StringBuffer reply = new StringBuffer();

        String output = JavascriptUtil.escapeJavaScript(ex.getMessage());
        String params = "{ name:'" + ex.getClass().getName() + "', message:'" + output + "' }";
        params += ", " + (batchId != null ? "'" + batchId + "'" : "null");

        reply.append(ProtocolConstants.SCRIPT_CALL_REPLY).append("\r\n");
        reply.append("dwr.engine.remote.handleBatchException(").append(params).append(");");

        return reply.toString();
    }

    /**
     * Call dwr.engine.remote.executeFunction() in the browser
     * @param id The registered function name
     * @param params The data to pass to the function
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteExecuteFunctionScript(String id, Object[] params)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleFunctionCall", id, params);
        return script;
    }

    /**
     * Call dwr.engine.remote.executeFunction() in the browser
     * @param id The registered function name
     * @param params The data to pass to the function
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteExecuteObjectScript(String id, String methodName, Object[] params)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleObjectCall", id, methodName, params);
        return script;
    }

    /**
     * Call dwr.engine.remote.executeFunction() in the browser
     * @param id The registered function name
     * @param propertyName The name of the property to alter on the client object
     * @param data The new value for the client object property
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteSetObjectScript(String id, String propertyName, Object data)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleSetCall", id, propertyName, data);
        return script;
    }

    /**
     * Call dwr.engine.remote.closeFunction() in the browser
     * @param id The registered function name
     * @return The script to send to the browser
     */
    public static ScriptBuffer getRemoteCloseFunctionScript(String id)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendCall("dwr.engine.remote.handleFunctionClose", id);
        return script;
    }

    /**
     * Call dwr.engine.remote.pollCometDisabled() in the browser
     * @param batchId The identifier of the batch that we are handling a response for
     * @return The script to send to the browser
     */
    public static String getRemotePollCometDisabledScript(String batchId)
    {
        StringBuffer reply = new StringBuffer();

        String params = "{name:'dwr.engine.pollAndCometDisabled',message:'Polling and Comet are disabled. See the server logs.'}";
        if (batchId != null)
        {
            params += ",'" + batchId + "'";
        }

        reply.append(ProtocolConstants.SCRIPT_CALL_REPLY).append("\r\n");
        reply.append("dwr.engine.remote.pollCometDisabled(").append(params).append(");");

        return reply.toString();
    }

    /**
     * Returns the name of the newObject function.
     */
    public static String remoteNewObjectFunction()
    {
        return "dwr.engine.remote.newObject";
    }

    /**
     * Take an XML string, and convert it into some Javascript that when
     * executed will return a DOM object that represents the same XML object
     * @param xml The XML string to convert
     * @return The Javascript
     */
    public static String xmlStringToJavascriptDomElement(String xml)
    {
        String xmlout = JavascriptUtil.escapeJavaScript(xml);
        return "dwr.engine.serialize.toDomElement(\"" + xmlout + "\")";
    }

    /**
     * Take an XML string, and convert it into some Javascript that when
     * executed will return a DOM object that represents the same XML object
     * @param xml The XML string to convert
     * @return The Javascript
     */
    public static String xmlStringToJavascriptDomDocument(String xml)
    {
        String xmlout = JavascriptUtil.escapeJavaScript(xml);
        return "dwr.engine.serialize.toDomDocument(\"" + xmlout + "\")";
    }

    /**
     * Get a string which will initialize a dwr.engine object
     * @return A dwr.engine init script
     */
    public static String getRequireEngineScript()
    {
        return "if (typeof dwr == 'undefined' || dwr.engine == undefined) throw new Error('You must include DWR engine before including this file');\n";
    }

    /**
     * The DefaultRemoter needs to know the name of the execute function
     * @return The execute function name
     */
    public static String getExecuteFunctionName()
    {
        return "dwr.engine._execute";
    }

    /**
     * A script to send at the beginning of an iframe response
     * @param batchId The id of the current batch
     * @param useWindowParent Will the exec happen from a child iframe which is
     * the case for normal iframe based calls, or from the main window, which is
     * the case for iframe streamed polling.
     * @return A script to init the environment
     */
    public static String remoteBeginIFrameResponse(String batchId, boolean useWindowParent)
    {
        return "dwr.engine.transport.iframe.remote.beginIFrameResponse(this.frameElement"+(batchId == null?"":",'" + batchId+"'") + ");";
    }

    /**
     * A script to send at the end of an iframe response
     * @param batchId The id of the current batch
     * @param useWindowParent Will the exec happen from a child iframe which is
     * the case for normal iframe based calls, or from the main window, which is
     * the case for iframe streamed polling.
     * @return A script to tidy up the environment
     */
    public static String remoteEndIFrameResponse(String batchId, boolean useWindowParent)
    {
        return "dwr.engine.transport.iframe.remote.endIFrameResponse("+(batchId == null?"":"'" + batchId+"'")+");";
    }

    /**
     * Prepare a script for execution in an iframe environment
     * (we need to transfer the script to the parent window context before executing so referred globals will be found)
     * @param script The script to modify
     * @return The modified script
     */
    public static String remoteExecute(String script)
    {
        return "dwr.engine._executeScript(\"" + JavascriptUtil.escapeJavaScript(script) + "\");";
    }
}