import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public void execute() throws BuildException {

    // Ensure that exactly one condition was specified.
    int numConditions = countConditions();
    if (numConditions != 1) {
      throw new BuildException("An 'if' must have exactly one condition (e.g. equal, and, etc.) - this 'if' has " + numConditions);
    }

    // Ensure that either a 'then' or an 'else' was specified.  An 'if' without one or the other is useless and probably a mistake.
    if ((seqThen == null) && (seqElse == null)) {
      throw new BuildException("An 'if' must have a 'then' and/or 'else' - this 'if' has neither.");
    }

    // Evaluate the condition and either do the 'then' or the 'else'.
    Condition condition = (Condition) getConditions().nextElement();
    Sequential task = condition.eval() ? seqThen : seqElse;
    if (task != null) {
      task.execute();
    }
  }
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public void execute() throws BuildException {
	if (value == null)
		throw new BuildException("Value is missing");
	if (cases.size() == 0 && defaultCase == null)
		throw new BuildException("No cases supplied");

	Sequential selectedCase = defaultCase;

	int sz = cases.size();
	for (int i = 0; i < sz; i++) {
		Case c = (Case) (cases.elementAt(i));

		String cvalue = c.value;
		if (cvalue == null) {
			throw new BuildException("Value is required for case.");
		}
		String mvalue = value;

		if (caseInsensitive) {
			cvalue = cvalue.toUpperCase();
			mvalue = mvalue.toUpperCase();
		}

		if (cvalue.equals(mvalue) && c != defaultCase)
			selectedCase = c;
	}

	if (selectedCase == null) {
		throw new BuildException("No case matched the value " + value + " and no default has been specified.");
	}
	selectedCase.perform();
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/***
 * Creates the <default> tag
 */
public void addDefault(Sequential res) throws BuildException {
	if (defaultCase != null)
		throw new BuildException("Cannot specify multiple default cases");

	defaultCase = res;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Embedded do sequential.
 * 
 * @param doTask
 *            the sequential to embed
 */
public void addSequential(Sequential doTask) {
	if (this.doTask != null) {
		throw new BuildException(
				"You must not nest more that one <parallel> or <sequential>" + " into <outofdate>");
	}
	this.doTask = doTask;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Adds a nested <try> block - one is required, more is forbidden.
 */
public void addTry(Sequential seq) throws BuildException {
	if (tryTasks != null) {
		throw new BuildException("You must not specify more than one <try>");
	}

	tryTasks = seq;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Adds a nested <finally> block - at most one is allowed.
 */
public void addFinally(Sequential seq) throws BuildException {
	if (finallyTasks != null) {
		throw new BuildException("You must not specify more than one <finally>");
	}

	finallyTasks = seq;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public void addThen(Sequential task) {

    if (seqThen != null) {
      throw new BuildException("An 'if' task can have only one 'then'.");
    }
    seqThen = task;
  }
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public void addElse(Sequential task) {

    if (seqElse != null) {
      throw new BuildException("An 'if' task can have only one 'else'.");
    }
    seqElse = task;
  }
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Creates and returns the <then> {@link Sequential}
 */
public Object createThen() {
    mThen = new Sequential();
    return mThen;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Creates and returns the <else> {@link Sequential}
 */
public Object createElse() {
    mElse = new Sequential();
    return mElse;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public Sequential createSequential() {
	this.sequential = (Sequential) getProject().createTask("sequential");
	return this.sequential;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
public void addThen(Sequential t) {
	if (thenTasks != null) {
		throw new BuildException("You must not nest more than one <then> into <elseif>");
	}
	thenTasks = t;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Add an application.
 * @param sequence the application to add.
 */
public void addApplication(Sequential sequence) {
    logOverride("application", application);
    application = sequence;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * Add a setup sequence.
 * @param sequence the setup sequence to add.
 */
public void addSetup(Sequential sequence) {
    logOverride("setup", setup);
    setup = sequence;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * add tests.
 * @param sequence a sequence to add.
 */
public void addTests(Sequential sequence) {
    logOverride("tests", tests);
    tests = sequence;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * set reporting sequence of tasks.
 * @param sequence a reporting sequence to use.
 */
public void addReporting(Sequential sequence) {
    logOverride("reporting", reporting);
    reporting = sequence;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * set teardown sequence of tasks.
 * @param sequence a teardown sequence to use.
 */
public void addTeardown(Sequential sequence) {
    logOverride("teardown", teardown);
    teardown = sequence;
}
 

import org.apache.tools.ant.taskdefs.Sequential; //导入依赖的package包/类
/**
 * A nested <else> element - a container of tasks that will be run if
 * the condition doesn't hold true.
 *
 * <p>
 * Not required.
 * </p>
 */
public void addElse(Sequential e) {
	if (elseTasks != null) {
		throw new BuildException("You must not nest more than one <else> into <if>");
	}
	elseTasks = e;
}