com.cognifide.slice.cq.taglib.CatchTag.java Source code

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Here is the source code for com.cognifide.slice.cq.taglib.CatchTag.java

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package com.cognifide.slice.cq.taglib;

/*
 * #%L
 * Slice - CQ Taglib
 * $Id:$
 * $HeadURL:$
 * %%
 * Copyright (C) 2012 Cognifide Limited
 * %%
 * 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.
 * #L%
 */

import java.io.PrintWriter;

import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TryCatchFinally;

import org.apache.commons.lang.StringUtils;

/**
 * Catches exceptions and renders their stack traces surrounded with <tt>&lt;pre&gt;</tt> tags, or as HTML
 * comments.
 * 
 * @author Albert Cenkier
 * @author Jan Kuniak
 */
public class CatchTag extends AbstractBodyTag implements TryCatchFinally {
    private static final long serialVersionUID = 3338066321193727755L;

    /** specifies name under which throwable variable is stored */
    private String throwableVariableName;

    public CatchTag() {
        init();
    }

    /** {@inheritDoc} */
    @Override
    public void release() {
        super.release();
        init();
    }

    private void init() {
        throwableVariableName = null;
    }

    /** {@inheritDoc} */
    @Override
    public int doStartTag() {
        // in case previous instance set a throwable under the same name
        if (StringUtils.isNotBlank(throwableVariableName)) {
            pageContext.removeAttribute(throwableVariableName, PageContext.PAGE_SCOPE);
        }
        return EVAL_BODY_INCLUDE;
    }

    /** {@inheritDoc} */
    @Override
    public void doCatch(Throwable t) {
        if (StringUtils.isNotBlank(throwableVariableName)) {
            pageContext.setAttribute(throwableVariableName, t, PageContext.PAGE_SCOPE);
        }

        logger.error("Exception in JSP", t);
        if (isRender()) {
            PrintWriter out = new PrintWriter(pageContext.getOut());
            out.println("<pre class=\"stacktrace\">");
            t.printStackTrace(out);
            out.println("</pre>");
        }
    }

    /** {@inheritDoc} */
    @Override
    public void doFinally() {
        // nothing to do here
    }

    /** @return the throwableVariableName */
    public String getThrowableVariableName() {
        return throwableVariableName;
    }

    /** @param throwableVariableName the throwableVariableName to set */
    public void setThrowableVariableName(String throwableVariableName) {
        this.throwableVariableName = throwableVariableName;
    }
}