antliscence/src/main/org/apache/tools/ant/taskdefs/Property.java

/*
 * The Apache Software License, Version 1.1
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 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.*;
import java.io.*;
import java.util.*;

/**
 * Will set a Project property. Used to be a hack in ProjectHelper
 * Will not override values set by the command line or parent projects.
 *
 * @author costin@dnt.ro
 * @author Sam Ruby <rubys@us.ibm.com>
 * @author Glenn McAllister <glennm@ca.ibm.com>
 */
public class Property extends Task {

    String name;
    String value;
    File file;
    String resource;

    boolean userProperty=false; // set read-only properties

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
	return name;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getValue() {
	return value;
    }

    public void setFile(File file) {
        this.file = file;
    }

    public File getFile() {
        return file;
    }

    public void setResource(String resource) {
        this.resource = resource;
    }

    public String getResource() {
        return resource;
    }

    public void execute() throws BuildException {
        try {
            if ((name != null) && (value != null)) {
                addProperty(name, value);
            }

            if (file != null) loadFile(file);

            if (resource != null) loadResource(resource);

        } catch (Exception e) {
            throw new BuildException(e, location);
        }
    }

    private void loadFile (File file) throws BuildException {
        Properties props = new Properties();
        log("Loading " + name, Project.MSG_VERBOSE);
        try {
            if (file.exists()) {
                props.load(new FileInputStream(file));
                addProperties(props);
            } else {
                log("Unable to find " + file.getAbsolutePath(), 
                    Project.MSG_VERBOSE);
            }
        } catch(Exception ex) {
            throw new BuildException(ex.getMessage(), ex, location);
        }
    }

    private void loadResource( String name ) {
        Properties props = new Properties();
        log("Resource Loading " + name, Project.MSG_VERBOSE);
        try {
            InputStream is = this.getClass().getResourceAsStream(name);
            if (is != null) {
                props.load(is);
                addProperties(props);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void addProperties(Properties props) {
        resolveAllProperties(props);
        Enumeration e = props.keys();
        while (e.hasMoreElements()) {
            String name = (String) e.nextElement();
            String value = (String) props.getProperty(name);
            String v = ProjectHelper.replaceProperties(value, project.getProperties());
            addProperty(name, value);
        }
    }

    public void setUserProperty( boolean userP ) {
	userProperty=userP;
    }

    private void addProperty(String n, String v) {
        if( userProperty ) {
            if (project.getUserProperty(n) == null) {
                project.setUserProperty(n, v);
            } else {
                log("Override ignored for " + n, Project.MSG_VERBOSE);
            } 
        } else {
            if (project.getProperty(n) == null) {
                project.setProperty(n, v);
            } else {
                log("Override ignored for " + n, Project.MSG_VERBOSE);
            }
        }
    }

    private void resolveAllProperties(Hashtable props) {
        Hashtable unresolvableProperties = new Hashtable();
        for (Enumeration e = props.keys(); e.hasMoreElements(); ) {
            String name = (String) e.nextElement();
            String value = (String) props.get(name);

            boolean resolved = false;
            while (!resolved) { 
                Vector propsInValue = new Vector();
    
                // assume it will be resolved
                resolved = true;
                boolean unresolvable = false;
                if (extractProperties(value, propsInValue)) {
                    for (int i=0; i < propsInValue.size(); i++) {
                        String elem = (String) propsInValue.elementAt(i);
                        if (elem.equals(name) || unresolvableProperties.containsKey(elem)) {
                            // we won't try further resolving elements with circular 
                            // property dependencies or dependencies on unresolvable elements
                            unresolvable = true;
                            break;
                        }
                        
                        if (project.getProperties().containsKey(elem) ||
                            props.containsKey(elem)) {
                            resolved = false;
                        }
                    }
                }
    
                if (unresolvable) {
                    unresolvableProperties.put(name, value);
                    resolved = true;
                }
    
                if (!resolved) {
                    value = ProjectHelper.replaceProperties(value,
                                                               project.getProperties());
                    value = ProjectHelper.replaceProperties(value, props);
                    props.put(name, value);
                }    
            }
        }
    }

    private boolean extractProperties(String source, Vector properties) {
        // This is an abreviated version of 
        // ProjectHelper.replaceProperties method
        int i=0;
        int prev=0;
        int pos;

        while( (pos=source.indexOf( "$", prev )) >= 0 ) {
            if( pos == (source.length() - 1)) {
                prev = pos + 1;
            } else if (source.charAt( pos + 1 ) != '{' ) {
                prev=pos+2;
            } else {
                int endName=source.indexOf( '}', pos );
                String n=source.substring( pos+2, endName );
                properties.addElement(n);
                prev=endName+1;
            }
        }
        
        return (properties.size() > 0);
    }
    
}