org.apache.hama.manager.util.UITemplate.java Source code

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Here is the source code for org.apache.hama.manager.util.UITemplate.java

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/**
 * 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.hama.manager.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * UI Template utility for Hama Manager.
 */
public class UITemplate {

    public static final Log LOG = LogFactory.getLog(UITemplate.class);

    private final static String AREA_BEGIN_OPEN_TAG = "<!--{area,begin,";
    private final static String AREA_END_OPEN_TAG = "<!--{area,end,";
    private final static String AREA_CLOSE_TAG = "}-->";
    private final static String[] ERROR_MESSAGE = { "[Error] The template File not exist. ",
            "[Error] The area does not exist. ", "[Error] <!--{area,end,..}--> does not exist. ",
            "[Error] <!--{area,begin,..}--> does not exist. " };

    /**
     * read template file contents
     * 
     * @param template fileName
     */
    public String load(String fileName) {

        File tempalteFile = new File(fileName);

        if (tempalteFile.isFile()) {
            return loadTemplateFile(fileName);
        } else {
            return loadTemplateResource(fileName);
        }
    }

    /**
     * read template file contents
     * 
     * @param template fileName
     */
    protected String loadTemplateFile(String fileName) {

        FileInputStream fis = null;
        int bytesRemain; // the number of remaining bytes
        StringBuilder sb = new StringBuilder();

        try {
            fis = new FileInputStream(fileName);

            while ((bytesRemain = fis.available()) > 0) {
                byte[] data = new byte[bytesRemain];
                int bytesRead = fis.read(data);
                if (bytesRead == -1) {
                    break;
                }
                sb.append(new String(data));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return sb.toString();
    }

    /**
     * read template file contents
     * 
     * @param template fileName
     */
    protected String loadTemplateResource(String fileName) {

        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        if (classLoader == null) {
            classLoader = this.getClass().getClassLoader();
        }

        InputStream is = classLoader.getResourceAsStream(fileName);
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        StringBuffer sb = new StringBuffer();
        String line;

        try {
            while ((line = br.readLine()) != null) {
                sb.append(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (isr != null) {
                try {
                    isr.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return sb.toString();
    }

    /**
     * Get the data corresponding to the area in the template
     * 
     * @param all template file data
     * @param areaName area name
     */
    public String getArea(String data, String areaName) {
        return getAreaTemplate(data, areaName);
    }

    /**
     * Get the data corresponding to the area in the template
     * 
     * @param data template file data
     * @param areaName area name
     */
    protected String getAreaTemplate(String data, String areaName) {

        String beginTag = AREA_BEGIN_OPEN_TAG + areaName + AREA_CLOSE_TAG;
        String endTag = AREA_END_OPEN_TAG + areaName + AREA_CLOSE_TAG;

        int beginIndex = data.indexOf(beginTag);
        if (beginIndex == -1) {
            return ERROR_MESSAGE[0] + areaName;
        }
        int endIndex = data.indexOf(endTag);
        if (endIndex == -1) {
            return ERROR_MESSAGE[2] + areaName;
        }
        return data.substring(beginIndex + beginTag.length(), endIndex);
    }

    /**
     * Replace the value of the variable in the data area
     * 
     * @param area area data
     * @param vars variables
     */
    public String convert(String area, HashMap<String, String> vars) {
        return convertVariable(area, vars);
    }

    /**
     * Replace the value of the variable in the data area
     * 
     * @param area area data
     * @param variables variables
     */
    public String convertVariable(String area, HashMap<String, String> variables) {

        StringBuffer sb = new StringBuffer();
        String variableName, variableValue;

        for (int i = 0; i < area.length(); i++) {
            if (area.charAt(i) == '$') {
                variableName = getVariableName(area, i);

                if (variableName == null) {
                    sb.append(area.charAt(i));
                } else {
                    variableValue = variables.get(variableName);
                    if (variableValue != null) {
                        sb.append(variableValue);
                    }
                    i += variableName.length() + 2;
                }
            } else {
                sb.append(area.charAt(i));
            }
        }

        return sb.toString();
    }

    /**
     * Replace the value of the variable in the data area
     * 
     * @param area area data
     * @param pos position to start the conversion
     */
    private String getVariableName(String area, int pos) {
        StringBuffer variableName = new StringBuffer("");
        boolean inVariableName = false;

        for (int i = pos + 1; i < area.length(); i++) {
            char ch = area.charAt(i);
            if ((ch != '{') && (!inVariableName)) {
                return null;
            }
            if (inVariableName) {
                if (ch == '}') {
                    return variableName.toString();
                }
                variableName.append(ch);
            }
            inVariableName = true;
        }
        return null;
    }

}