org.unix4j.unix.xargs.XargsOptions Maven / Gradle / Ivy
package org.unix4j.unix.xargs;
import java.util.Collections;
import java.util.Iterator;
import org.unix4j.convert.OptionSetConverters.OptionSetConverter;
import org.unix4j.convert.ValueConverter;
import org.unix4j.option.DefaultOptionSet;
import org.unix4j.option.Option;
import org.unix4j.option.OptionSet;
import org.unix4j.unix.Xargs;
import org.unix4j.unix.xargs.XargsOption;
/**
* Interface implemented by all option sets for the {@link Xargs xargs} command.
* It is recommended to use {@link Xargs#Options} to specify a valid
* combination of options.
*
* The options for the xargs command are:
*
*
* {@code -z} {@code --delimiter0} Input items are terminated by a null character instead of by
whitespace, and the quotes and backslash are not special (every
character is taken literally). Disables the end of file string,
which is treated like any other argument. Useful when input items
might contain white space, quote marks, or backslashes. The find
--print0 option produces input suitable for this mode.
(This option is ignored if an explicit delimiter operand is specified).
{@code -x} {@code --exactArgs} Terminate immediately if {@code maxArgs} is specified but the found
number of variable items is less than {@code maxArgs}.
(This option is ignored if no {@code maxArgs} operand is specified).
{@code -r} {@code --noRunIfEmpty} If the standard input does not contain any nonblanks, do not run the
command. Normally, the command is run once even if there is no
input. {@code -t} {@code --verbose} Print the command line on the standard error output before executing
it.
*
* This interface serves as an alias for the extended interface to simplify the
* command signature methods by avoiding generic parameters.
*/
public interface XargsOptions extends OptionSet {
/**
* Constant for an empty option set.
*/
XargsOptions EMPTY = new XargsOptions() {
@Override
public Class optionType() {
return XargsOption.class;
}
@Override
public boolean isSet(XargsOption option) {
return false;
}
/**
* Returns 0 as this is a set with no active options.
*
* @return zero
*/
@Override
public int size() {
return 0;
}
/**
* Returns an immutable empty set.
*
* @return an immutable empty set.
*/
@Override
public java.util.Set asSet() {
return Collections.emptySet();
}
/**
* Returns an iterator returning no elements.
*
* @return an immutable iterator with no elements.
*/
@Override
public Iterator iterator() {
return asSet().iterator();
}
/**
* Returns true if the {@link Option#acronym() acronym} should be used
* for the specified {@code option} in string representations.
*
* This method returns always true;
*
* @param option
* the option of interest
* @return always true
*/
@Override
public boolean useAcronymFor(XargsOption option) {
return true;
}
};
/**
* Default implementation for a modifiable option set.
*/
class Default extends DefaultOptionSet implements XargsOptions {
/**
* Default constructor for an empty option set with no active options.
*/
public Default() {
super(XargsOption.class);
}
/**
* Constructor for an option set with a single active option.
* @param option the option to be set
*/
public Default(XargsOption option) {
super(option);
}
/**
* Constructor for an option set with the given active options.
* @param options the options to be set
*/
public Default(XargsOption... options) {
this();
setAll(options);
}
/**
* Constructor for an option set initialized with the options given by
* another option set.
*
* @param optionSet set with the options to be active
*/
public Default(OptionSet optionSet) {
this();
setAll(optionSet);
}
}
/**
* Value converter for {@link XargsOptions} based on an {@link OptionSetConverter}.
*/
ValueConverter CONVERTER = new ValueConverter() {
private final OptionSetConverter converter = new OptionSetConverter(XargsOption.class);
@Override
public XargsOptions convert(Object value) {
final OptionSet set = converter.convert(value);
return set == null ? null : new Default(set);
}
};
}