parameterlist.java

来自「jpeg2000编解码」· Java 代码 · 共 484 行 · 第 1/2 页

     * @param pname The parameter name.
     *
     * @return the value of the parameter as a string, or null if there is no
     * parameter with the name 'pname'.
     * */
    public String getParameter(String pname) {
        String pval;

        pval = (String) get(pname);
        if (pval == null && defaults != null) { // if parameter is not there
            // Look in defaults
            pval = defaults.getProperty(pname);
        }
        return pval;
    }

    /**
     * Returns the value of the named parameter as a boolean. The value "on"
     * is interpreted as 'true', while the value "off" is interpreted as
     * 'false'. If the parameter has another value then an
     * StringFormatException is thrown. If the parameter 'pname' is not in the
     * parameter list, an IllegalArgumentException is thrown.
     *
     * @param pname The parameter name.
     *
     * @return the value of the parameter as a boolean.
     *
     * @exception StringFormatException If the parameter has a value which is
     * neither "on" nor "off".
     *
     * @exception IllegalArgumentException If there is no parameter with the
     * name 'pname' in the parameter list.
     * */
    public boolean getBooleanParameter(String pname) {
        String s = (String) getParameter(pname);

        if (s == null) {
            throw new IllegalArgumentException("No parameter with name "+
                                               pname);
        }
        else if (s.equals("on")) {
            return true;
        }
        else if (s.equals("off")) {
            return false;
        }
        else {
            throw new StringFormatException("Parameter \""+pname+
                                            "\" is not boolean: " + s);
        }
    }

    /**
     * Returns the value of the named parameter as an int. If the parameter
     * has a non-numeric value a NumberFormatException is thrown. If the
     * parameter has a multiple word value than the first word is returned as
     * an int, others are ignored. If the parameter 'pname' is not in the
     * parameter list, an IllegalArgumentException is thrown.
     *
     * @param pname The parameter name.
     *
     * @return the value of the parameter as an int.
     *
     * @exception NumberFormatException If the parameter has a non-numeric
     * value.
     *
     * @exception IllegalArgumentException If there is no parameter with the
     * name 'pname' in the parameter list.
     * */
    public int getIntParameter(String pname) { 
        String s = (String) getParameter(pname);

        if (s == null) {
            throw new IllegalArgumentException("No parameter with name "+
                                               pname);
        }
        else {
            try {
                return Integer.parseInt(s);
            }
            catch (NumberFormatException e) {
                throw new NumberFormatException("Parameter \""+pname+
                                                "\" is not integer: "
                                                + e.getMessage());
            }
        }
   }

    /**
     * Returns the value of the named parameter as a float. If the parameter
     * has a non-numeric value a NumberFormatException is thrown. If the
     * parameter has a multiple word value than the first word is returned as
     * an int, others are ignored. If the parameter 'pname' is not in the
     * parameter list, an IllegalArgumentException is thrown.
     *
     * @param pname The parameter name.
     *
     * @exception NumberFormatException If the parameter has a non-numeric
     * value.
     *
     * @exception IllegalArgumentException If there is no parameter with the
     * name 'pname' in the parameter list.
     *
     * @return the value of the parameter as a float.
     * */
    public float getFloatParameter(String pname) {
        String s = (String) getParameter(pname);

        if (s == null) {
            throw new IllegalArgumentException("No parameter with name "+
                                               pname);
        }
        else {
            try {
                // Unfortunately there is no method to convert from a string
                // directly to a float
                return (new Float(s)).floatValue();
            }
            catch (NumberFormatException e) {
                throw new NumberFormatException("Parameter \""+pname+
                                                "\" is not floating-point: "
                                                + e.getMessage());
            }
        }
    }

    /**
     * Checks if the parameters which name starts with the prefix 'prfx' in
     * the parameter list are all in the list of valid parameter names
     * 'plist'. If there is a parameter that is not in 'plist' an
     * IllegalArgumentException is thrown with an explanation message. The
     * default parameters are also included in the check.
     *
     * @param prfx The prefix of parameters to check.
     *
     * @param plist The list of valid parameter names for the 'prfx'
     * prefix. If null it is considered that no names are valid.
     *
     * @exception IllegalArgumentException If there's a parameter name
     * starting with 'prfx' which is not in the valid list of parameter names.
     * */
    public void checkList(char prfx, String plist[]) {
        Enumeration args;
        String val;
        int i;
        boolean isvalid;

        args = propertyNames();

        while (args.hasMoreElements()) {
            val = (String) args.nextElement();
            if (val.length() > 0 && val.charAt(0) == prfx) {
                isvalid = false;
                if (plist != null) {
                    for (i=plist.length-1; i>=0; i--) {
                        if (val.equals(plist[i])) {
                            isvalid = true;
                            break;
                        }
                    }
                }
                if (!isvalid) { // Did not find valid flag
                    throw new IllegalArgumentException("Option '"+val+"' is "+
                                                       "not a valid one.");
                }
            }
        }
    }

    /**
     * Checks if the parameters which names do not start with any of the
     * prefixes in 'prfxs' in this ParameterList are all in the list of valid
     * parameter names 'plist'. If there is a parameter that is not in 'plist'
     * an IllegalArgumentException is thrown with an explanation message. The
     * default parameters are also included in the check.
     *
     * @param prfxs The prefixes of parameters to ignore.
     *
     * @param plist The list of valid parameter names. If null it is
     * considered that no names are valid.
     *
     * @exception IllegalArgumentException If there's a parameter name not
     * starting with 'prfx' which is not in the valid list of parameter names.
     * */
    public void checkList(char prfxs[], String plist[]) {
        Enumeration args;
        String val,strprfxs;
        int i;
        boolean isvalid;

        args = propertyNames();
        strprfxs = new String(prfxs);

        while (args.hasMoreElements()) {
            val = (String) args.nextElement();
            if (val.length() > 0 && strprfxs.indexOf(val.charAt(0)) == -1) {
                isvalid = false;
                if (plist != null) {
                    for (i=plist.length-1; i>=0; i--) {
                        if (val.equals(plist[i])) {
                            isvalid = true;
                            break;
                        }
                    }
                }
                if (!isvalid) {
                    throw new IllegalArgumentException("Option '"+val+"' is "+
                                                       "not a valid one.");
                }
            }
        }
    }

    /**
     * Converts the usage information to a list of parameter names in a single
     * array. The usage information appears in a 2D array of String. The first
     * dimensions contains the different options, the second dimension
     * contains the name of the option (first element), the synopsis and the
     * explanation. This method takes the names of the different options in
     * 'pinfo' and returns them in a single array of String.
     *
     * @param pinfo The list of options and their usage info (see above).
     *
     * @return An array with the names of the options in pinfo. If pinfo is
     * null, null is returned.
     * */
    public static String[] toNameArray(String pinfo[][]) {
        String pnames[];

        if (pinfo == null) {
            return null;
        }

        pnames = new String[pinfo.length];

        for (int i=pinfo.length-1; i>=0; i--) {
            pnames[i] = pinfo[i][0];
        }
        return pnames;
    }
}